Saliva of Aedes aegypti contains a complex array of proteins essential for both blood feeding and pathogen transmission. A large numbers of those proteins are classified as unknown in regard to their function(s). Understanding the dynamic interactions at the mosquito-host interface can be achieved in part by characterizing mosquito salivary gland gene expression relative to blood feeding. Towards this end, we developed an oligonucleotide microarray representing 463 transcripts to determine differential regulation of salivary gland genes. This microarray was used to investigate the temporal gene expression pattern of Ae. aegypti salivary gland transcriptome at different times post-blood feeding. Expression of the majority of salivary gland genes (77–87%) did not change significantly as a result of blood feeding, while 8 to 20% of genes were down-regulated and 2.8 to 11.6% genes were up-regulated. Up-regulated genes included defensins, mucins and other immune related proteins. Odorant-binding protein was significantly down-regulated. Among unknown function proteins, several were up-regulated during the first three hours post-blood feeding and one was significantly down-regulated. Quantitative real-time RT-PCR was used to substantiate differential expression patterns of five randomly selected genes. Linear regression analysis revealed a high degree of correlation (R2 > 0.89) between oligonucleotide microarray and quantitative RT-PCR data. To our knowledge, this is the first study to investigate differential expression of the Ae. aegypti salivary gland transcriptome upon blood feeding. A microarray provides a robust, sensitive way to investigate differential regulation of mosquito salivary gland genes.
The malaria parasite sporozoite transmission stage develops and differentiates within parasite oocysts on the Anopheles mosquito midgut. Successful inoculation of the parasite into a mammalian host is critically dependent on the sporozoite's ability to first infect the mosquito salivary glands. Remarkable changes in tissue infection competence are observed as the sporozoites transit from the midgut oocysts to the salivary glands. Our microarray analysis shows that compared to oocyst sporozoites, salivary gland sporozoites upregulate expression of at least 124 unique genes. Conversely, oocyst sporozoites show upregulation of at least 47 genes (upregulated in oocyst sporozoites [UOS genes]) before they infect the salivary glands. Targeted gene deletion of UOS3, encoding a putative transmembrane protein with a thrombospondin repeat that localizes to the sporozoite secretory organelles, rendered oocyst sporozoites unable to infect the mosquito salivary glands but maintained the parasites' liver infection competence. This phenotype demonstrates the significance of differential UOS expression. Thus, the UIS-UOS gene classification provides a framework to elucidate the infectivity and transmission success of Plasmodium sporozoites on a whole-genome scale. Genes identified herein might represent targets for vector-based transmission blocking strategies (UOS genes), as well as strategies that prevent mammalian host infection (UIS genes).
Interleukin-12 (IL-12) is a pleiotropic cytokine and is elevated in affected organs of Sjögren's syndrome (SS) patients. We have previously reported in CBA mice that over-expression of IL-12 leads to mononuclear infiltration of salivary and lacrimal glands, as well as expansion of bronchial lymphoid tissue and decreased mucociliary clearance. Xerostomia is one of the most important clinical features in SS patients, therefore our main objective was to evaluate the salivary gland function in IL-12 transgenic mice. Our secondary objective was to further characterize this animal model and see if these changes are representative for SS.
Pilocarpine-stimulated salivary flow was used to address salivary gland function in a large group of mice IL-12 transgenic mice bred onto the autoimmune-prone SJL background. Furthermore, salivary glands were removed at different time points to assess the formation of infiltrates in the glands and gland morphology. Serum was also collected from these animals to investigate the formation of autoantibodies.
Pilocarpine-stimulated salivary flow was significantly lower in IL-12 transgenics compared with wild type controls. Salivary glands from transgenic mice showed both a greater number and size of lymphocytic foci than those of age-matched controls. Furthermore, their acini were fewer and larger compared with controls. Anti-La antibodies showed an age-dependent increase in IL-12 transgenic mice, accompanied by a rise in anti-nuclear antibodies.
Our findings indicate that SJL IL-12 transgenic mice express a number of conditions associated with SS and may serve as a useful model for research on multiple aspects of the disease.
Radiation therapy for head and neck cancer causes adverse secondary side effects in the salivary glands and results in diminished quality of life for the patient. A previous in vivo study in parotid salivary glands demonstrated that targeted head and neck irradiation resulted in marked increases in phosphorylated p53 (serine18) and apoptosis, which was suppressed in transgenic mice expressing a constitutively active mutant of Akt1 (myr-Akt1).
Methods and Materials
Transgenic and knockout mouse models were exposed to irradiation and p53-mediated transcription, apoptosis, and salivary gland dysfunction were analyzed.
We report that the pro-apoptotic p53 target genes PUMA and Bax are induced in parotid salivary glands of mice at early time points following therapeutic radiation. This dose-dependent induction requires expression of p53 as no radiation-induced expression of PUMA and Bax is observed in p53−/− mice. Radiation also induces apoptosis in the parotid gland in a dose dependent manner, which is p53-dependent. Furthermore, expression of p53 is required for the acute and chronic loss of salivary function following irradiation. In contrast, p53−/− mice do not induce apoptosis and preserve salivary function after radiation exposure.
These results indicate that apoptosis in the salivary glands following therapeutic head and neck irradiation is mediated by p53 and corresponds to salivary gland dysfunction in vivo.
We report for the first time that saliva of the hard tick and Lyme disease vector, Ixodes scapularis, is a potent inhibitor of angiogenesis. Saliva (≤ 1:500 dilutions) or salivary gland (0.1–0.5 pairs/assay) dose-dependently inhibits microvascular endothelial cell (MVEC) proliferation. Inhibition was also detected with the saliva of the cattle tick Boophilus microplus but not with the salivary gland of Anopheles gambiae, An. stephensiae, Lutzomyia longipalpis, Phlebotomus papatasi, Aedes aegypti, Culex quinquefasciatus, and Cimex lectularius. Inhibition of MVEC proliferation by I. scapularis saliva was accompanied by a change in cell shape (shrinkage of the cytoplasm with loss of cell-cell interactions) and apoptosis which was estimated by expression of phosphatidylserine using the Apopercentage dye, and by a typical pattern of chromatin margination, condensation, and fragmentation as revealed by nuclear staining with Hoechst 33258. The effect of saliva appears to be mediated by endothelial cell α5β1 integrin, because monoclonal antibodies against this but not αvβ3, αvβ5, α9β1, or α2β1 integrins remarkably block its effect. In addition, SDS/PAGE shows that saliva specifically degrades purified α5β1 but not αvβ5 or αvβ3 integrins. Incubation of saliva with EDTA and 1,10-phenanthroline, but not phenylmethylsulfonyl fluoride (PMSF), inhibits saliva-dependent degradation of purified α5β1 integrin, suggesting that a metalloprotease is responsible for the activity. Finally, saliva at ≤ 1:1,000 dilution blocks sprouting formation from chick embryo aorta implanted in Matrigel, an in vitro model of angiogenesis. These findings introduce the concept that tick saliva is a negative modulator of angiogenesis-dependent wound healing and tissue repair, therefore allowing ticks to feed for days. Inhibition of angiogenesis was hitherto an unidentified biologic property of the saliva of any blood-sucking arthropod studied so far. Its presence in tick saliva may be regarded as an additional source of angiogenesis inhibitors with potential applications for the study of both vector and vascular biology.
Epithelial and especially mucosal immunity represents the first line of defence against the plethora of potential pathogens trying to invade via the gastrointestinal tract. The salivary glands of the fruit fly are an indispensable part of the gastrointestinal tract, but their contribution to the mucosal immunity has almost completely been neglected. Our major goal was to elucidate if the fly's salivary glands are able to mount an immune response and what the major characteristics of this immune response are.
Ectopic activation of the IMD-pathway within the salivary gland cells is able to induce an immune response, indicating that the salivary glands are indeed immune competent. This reaction is characterized by the concurrent expression of numerous antimicrobial peptide genes. In addition, ectopic activation of the salivary gland's immune response induces morphological changes such as dwarfism throughout all developmental stages and a significantly decreased length of the salivary glands themselves. DNA-microarray analyses of the reaction revealed a complex pattern of up- and downregulated genes. Gene ontology analyses of regulated genes revealed a significant increase in genes associated with ribosomal and proteasomal function. On the other hand, genes coding for peptide receptors and some potassium channels are downregulated. In addition, the comparison of the transcriptional events induced following IMD-activation in the trachea and the salivary glands shows also only a small overlap, indicating that the general IMD-activated core transcriptome is rather small and that the tissue specific component of this response is dominating. Among the regulated genes, those that code for signaling associated protease activity are significantly modulated.
The salivary glands are immune-competent and they contribute to the overall intestinal immune system. Although they produce antimicrobial peptides, their overall response is highly tissue-specific. Our analysis indicates that chronic activation of the salivary gland's immune system is costly, as it induces severe reduction in growth throughout development. The IMD-regulated increase in expression levels of the fly's presenilin representatives opens the opportunity to use the salivary glands for studying the physiological and pathophysiological role of these genes in a simple but functional environment.
Antibody responses against Anopheles salivary proteins can indicate individual exposure to bites of malaria vectors. The extent to which these salivary proteins are species-specific is not entirely resolved. Thus, a better knowledge of the diversity among salivary protein repertoires from various malaria vector species is necessary to select relevant genus-, subgenus- and/or species-specific salivary antigens. Such antigens could be used for quantitative (mosquito density) and qualitative (mosquito species) immunological evaluation of malaria vectors/host contact. In this study, salivary gland protein repertoires (sialomes) from several Anopheles species were compared using in silico analysis and proteomics. The antigenic diversity of salivary gland proteins among different Anopheles species was also examined.
In silico analysis of secreted salivary gland protein sequences retrieved from an NCBInr database of six Anopheles species belonging to the Cellia subgenus (An. gambiae, An. arabiensis, An. stephensi and An. funestus) and Nyssorhynchus subgenus (An. albimanus and An. darlingi) displayed a higher degree of similarity compared to salivary proteins from closely related Anopheles species. Additionally, computational hierarchical clustering allowed identification of genus-, subgenus- and species-specific salivary proteins. Proteomic and immunoblot analyses performed on salivary gland extracts from four Anopheles species (An. gambiae, An. arabiensis, An. stephensi and An. albimanus) indicated that heterogeneity of the salivary proteome and antigenic proteins was lower among closely related anopheline species and increased with phylogenetic distance.
This is the first report on the diversity of the salivary protein repertoire among species from the Anopheles genus at the protein level. This work demonstrates that a molecular diversity is exhibited among salivary proteins from closely related species despite their common pharmacological activities. The involvement of these proteins as antigenic candidates for genus-, subgenus- or species-specific immunological evaluation of individual exposure to Anopheles bites is discussed.
Anopheles; Salivary proteins; Sequence alignment; Biomarkers; Malaria vectors; Protein diversity
To determine the impact of highly active antiretroviral therapy (HAART) on salivary gland function in HIV positive women from the Women's Interagency HIV Study (WIHS).
Longitudinal cohort study.
Subjects and Methods
A total of 668 HIV positive women from the WIHS cohort with an initial and at least 1 follow-up oral sub-study visit contributed 5358 visits. Salivary gland function was assessed based on a dry mouth questionnaire, whole unstimulated and stimulated salivary flow rates, salivary gland enlargement or tenderness and lack of saliva on palpation of the major salivary glands.
Main Outcome Measures
Changes in unstimulated and stimulated flow rates at any given visit from that of the immediate prior visit (continuous variables). The development of self-reported dry mouth (present/absent), enlargement or tenderness of salivary glands (present/absent), and absence of secretion on palpation of the salivary glands were binary outcomes (yes/no).
Protease Inhibitor (PI) based HAART was a significant risk factor for developing decreased unstimulated (p=0.01) and stimulated (p=0.0004) salivary flow rates as well as salivary gland enlargement (p=0.006) as compared with non-PI based HAART.
PI-based HAART therapy is a significant risk factor for developing reduced salivary flow rates and salivary gland enlargement in HIV positive patients.
HIV; antiretroviral therapy; HAART; salivary gland function; salivary gland enlargement; PI based HAART
The exposure to high doses of ionizing radiation during radiotherapy results in severe morphological and functional alterations of the salivary glands, such as xerostomia. In the present study we investigated the chronic effect of a single radiation dose of 15 Gray (Gy) limited to head and neck on rat salivary gland function (salivary secretion and gland mass) and histology. Results indicate that norepinephrine (NE)-induced salivary secretion was reduced significantly at 30, 90, 180 and 365 days after the administration of a single dose of 15 Gy of ionizing radiation compared to non-irradiated animals. The maximal secretory response was reduced by 33% at 30 and 90 days post irradiation. Interestingly, a new fall in the salivary response to NE was observed at 180 days and was maintained at 365 days post irradiation, showing a 75% reduction in the maximal response. The functional fall of the salivary secretion observed at 180 days post irradiation was not only associated with a reduction of gland mass but also to an alteration of the epithelial architecture exhibiting a changed proportion of ducts and acini, loss of eosinophilic secretor granular material, and glandular vacuolization and fibrosis. On the basis of the presented results, we conclude that ionizing radiation produces irreversible and progressive alterations of submandibular gland (SMG) function and morphology that leads to a severe salivary hypo-function.
Radiotherapy; xerostomia; submandibular gland; salivary secretion.
The salivary proteome is a complex protein mixture resulting from the activity of salivary glands with the contribution of other components that form the oral environment such as oral tissues and micro-organisms. For diagnosis purposes, saliva collection has the great advantage of being an easy and non-invasive technique. Human saliva proteomics have proven to be a novel approach in the search for protein biomarkers for detection of different local and systemic diseases. Currently, more than 1400 salivary proteins have been identified. In the last few years, our research group has extensively studied the salivary proteomics in order to analyse the salivary composition, investigating the major families of proteins present in human and mammalian saliva, the post-translational modifications, the different contributions of glands, the physiological and pathological modifications of saliva. The aim of this report is to present our personal experience in salivary proteomics. In conclusion, salivary proteome analysis represents an important field both for diagnosis and monitoring of various diseases and could be considered a novel approach to prevention of various pathological conditions.
Saliva; Salivary glands; Proteomics; Salivary composition; HPLC-ESI-MS
Diseases of the salivary glands are rare in infants and children (with the exception of diseases such as parotitis epidemica and cytomegaly) and the therapeutic regimen differs from that in adults. It is therefore all the more important to gain exact and extensive insight into general and special aspects of pathological changes of the salivary glands in these age groups. Etiology and pathogenesis of these entities is still not yet fully known for the age group in question so that general rules for treatment, based on clinical experience, cannot be given, particularly in view of the small number of cases of the different diseases. Swellings of the salivary glands may be caused by acute and chronic inflammatory processes, by autoimmune diseases, by duct translocation due to sialolithiasis, and by tumors of varying dignity. Clinical examination and diagnosis has also to differentiate between salivary gland cysts and inflammation or tumors.
Salivary gland diseases are rare in childhood and adolescence. Their pattern of incidence differs very much from that of adults. Acute and chronic sialadenitis not responding to conservative treatment requires an appropriate surgical approach. The rareness of salivary gland tumors is particularly true for the malignant parotid tumors which are more frequent in juvenile patients, a fact that has to be considered in diagnosis and therapy.
Many eukaryotic developmental and cell fate decisions that are effected
post-transcriptionally involve RNA binding proteins as regulators of translation
of key mRNAs. In malaria parasites (Plasmodium spp.), the
development of round, non-motile and replicating exo-erythrocytic liver stage
forms from slender, motile and cell-cycle arrested sporozoites is believed to
depend on environmental changes experienced during the transmission of the
parasite from the mosquito vector to the vertebrate host. Here we identify a
Plasmodium member of the RNA binding protein family PUF as
a key regulator of this transformation. In the absence of Pumilio-2 (Puf2)
sporozoites initiate EEF development inside mosquito salivary glands
independently of the normal transmission-associated environmental cues.
Puf2- sporozoites exhibit genome-wide transcriptional
changes that result in loss of gliding motility, cell traversal ability and
reduction in infectivity, and, moreover, trigger metamorphosis typical of early
Plasmodium intra-hepatic development. These data
demonstrate that Puf2 is a key player in regulating sporozoite developmental
control, and imply that transformation of salivary gland-resident sporozoites
into liver stage-like parasites is regulated by a post-transcriptional
Injection of Plasmodium sporozoites by
Anopheles mosquitoes into the human host initiates malaria
infection. Generation of blood stage parasites leading to the onset of disease
relies on the successful development of the sporozoite into merozoites in the
liver. Here we show that in the rodent malaria model Plasmodium
berghei these developmental transformations are controlled by the
RNA binding protein Pumilio 2 (Puf2). In the absence of Puf2, sporozoites, while
still in the mosquito salivary gland, slowly transform into early stage
exo-erythrocytic form parasites without the need for any environmental signals.
Morphologically precocious metamorphosis is characterized by the loss of the
inner membrane complex and the generation of clear protrusions which result in
round liver stage-like parasites. The transcriptional alterations are consistent
with developmental adaptations that occur during sporozoite to liver stage-like
developmental progression. In total, 90% of up-regulated genes in mutant
parasites have only been identified in liver stage parasite proteomes, but not
the sporozoite proteome. Plasmodium Puf2, a member of the
Pumillo family known to be involved in key developmental decisions in many
different organisms, acts as a clear regulator of life cycle progression during
sporozoite transmission from the mosquito vector to the mammalian host.
Salivary glands are usually irradiated during radiotherapy for head and neck cancers, which can lead to radiation-induced damage. Radiation-induced xerostomia (oral dryness) is the most common post-radiotherapy complication for head and neck cancer patients and can reduce the patient’s quality of life. Accurate and efficient salivary gland assessment methods provide a better understanding of the cause and degree of xerostomia, and may help in patient management. At present, there are different methods for the assessment of salivary gland hypofunction; however, none of them are considered to be standard procedure. This article reviews the value of common methods in the assessment of post-radiotherapy salivary glands.
Salivary gland dysfunction is one of the key manifestations of Sjögren's syndrome.
(1) To assess prospectively loss of function of individual salivary glands in patients with primary and secondary Sjögren's syndrome in relation to disease duration and use of immunomodulatory drugs. (2) To study changes in sialochemical and laboratory values and subjective complaints over time.
60 patients with Sjögren's syndrome were included in this study. Whole and gland‐specific saliva (parotid and submandibular/sublingual (SM/SL)), samples were collected at baseline and after a mean of 3.6 (SD 2.3) years of follow‐up. Disease duration was recorded for all patients.
Patients with Sjögren's syndrome with short disease duration had significantly higher stimulated flow rates at baseline than those with longer disease duration (p<0.05). When compared with healthy controls, the decrease in SM/SL flow rates at baseline was more prominent than that in parotid flow rates (p<0.05). Over time, there was a significant further decrease of stimulated flow rates, especially of the parotid gland, accompanied by increasing problems with swallowing dry food (p<0.05). The decrease was independent of the use of corticosteroids or disease‐modifying antirheumatic drugs (DMARDs). Sialochemical variables remained stable.
Early Sjögren's syndrome is characterised by a decreased salivary gland function (parotis>SM/SL), which shows a further decrease over time, regardless of the use of DMARDs or steroids. Patients with Sjögren's syndrome with longer disease duration are characterised by severely reduced secretions of both the parotid and SM/SL glands. These observations are relevant for identifying patients who would most likely benefit from intervention treatment.
Development of accurate therapeutic approaches to salivary gland neoplasms depends on better understanding of their molecular pathogenesis. Tumour growth is regulated by the balance between proliferation and apoptosis. Few studies have investigated apoptosis in salivary tumours relying almost exclusively on immunohistochemistry or TUNEL assay. Furthermore, there is no information regarding the mRNA expression profile of apoptotic genes in salivary tumors. Our objective was to investigate the quantitative expression of BCL-2 (anti-apoptotic), BAX and Caspase3 (pro-apoptotic genes) mRNAs in salivary gland neoplasms and examine the association of these data with tumour size, proliferative activity and p53 staining (parameters associated with a poor prognosis of salivary tumours patients).
We investigated the apoptotic profile of salivary neoplasms in twenty fresh samples of benign and seven samples of malignant salivary neoplasms, using quantitative real time PCR. We further assessed p53 and ki-67 immunopositivity and obtained clinical tumour size data.
We demonstrated that BCL-2 mRNA is overexpressed in salivary neoplasms, leading to an overall anti-apoptotic profile. We also found an association between the anti-apoptotic index (BCL-2/BAX) with p53 immunoexpression. A higher proliferative activity was found in the malignant tumours. In addition, tumour size was associated with cell proliferation but not with the transcription of apoptotic genes.
In conclusion, we show an anti-apoptotic gene expression profile in salivary neoplasms in association with p53 staining, but independent of cell proliferation and tumour size.
Salivary gland neoplasms; Pleomorphic adenoma; Apoptosis; Bcl-2; Bax; Caspase 3; Transcription; p53; Cell proliferation; Tumour size
Information on the biology of metastasis development in salivary gland tumors is scarce. Since angiogenesis seems associated with this phenomenon in other tumors, we sought to compare salivary gland tumors with diverse metastatic behavior in order to improve the knowledge and management of these lesions.
Samples from the most important salivary gland tumors were segregated according to its metastatic behavior and submitted to routine immunohistochemistry to identify vessels positive for CD105 expression. Frequency of positive cases and intratumoral microvessel density (IMD) was compared among the group of lesions.
CD105 positive vessels were absent in normal salivary gland tissue, were rare in pleomorphic adenomas and adenoid cystic carcinomas (ACC), more common in polymorphous low-grade adenocarcinomas and highest in mucoepidermoid carcinomas. Only ACC with such feature were metastatic. IMD was higher in malignant rather than benign tumors.
Immunostaining of CD105 in salivary gland tumors implies participation of angiogenesis in the development of malignant lesions, as well as some role for myoepithelial cells in the control of new vessel formation. In addition, suggest that ACC with positive CD105 vessels are at higher risk for metastasis.
Dengue virus serotype 2 (DENV-2) RNA replication profiles and tropisms were studied by using quantitative RT-PCR (q-RTPCR) in intrathoracically infected Aedes albopictus. The virus RNA replication profiles were diverse in mosquito organs. In fat body, brain, salivary gland, and malpighian tubes, it peaked at 8, 23, 23, and 27 days post-infection, respectively, and then, all declined. In midgut, it increased all the time and had no trend of decline. In ovary, it had no apparent increase. Subsequent Western blotting of DENV-2 E protein had similar results. Using ribosomal protein 7 (rpS7) as an internal control, we found that, in salivary gland, brain, fat body, and midgut, the average DENV-2 RNA levels (DENV-2 RNA/rpS7 mRNA) were 1,028, 464, 5.6, and 6.2, respectively; in malpighian tubes, it was 1, and in ovary, it was far less than 1. These results suggest that infection profiles and tropism of DENV-2 RNA in Ae. albopictus organs are significantly different.
To investigate the effect of botulinum toxin type A (BTXA) on drooling and the morphologic change of the salivary gland in patients with cerebral palsy.
Eight cerebral palsy patients suffering from severe drooling participated in this study. BTXA was injected into both submandibular and parotid glands under intravenous sedation and with ultrasound guidance (1 unit/gland/kg: maximum 100 units) in an outpatient or inpatient procedure. The severity of drooling was measured before injection and 3 weeks after injection using the Teacher Drooling Scale, the Drooling Score-severity, frequency and the Visual Analog Scale. To investigate the morphologic change of the salivary glands, the size of salivary glands were measured before injection and 3 weeks after injection using computed tomography of the neck. The measurement values were analyzed by Wilcoxon signed rank test.
Statistically significant improvements were shown in all three parameters for assessing the severity of drooling after BTXA injections (p<0.05). Size of the salivary glands were significantly decreased at 3 weeks after BTXA injection (p<0.05).
Salivary gland injection with BTXA could be a useful treatment method to reduce drooling in patients with cerebral palsy and decreased size of salivary glands may partially explain the mechanism.
Botulinum toxin type A; Drooling; Size of salivary gland
A modified Mantel-Haenszel analysis of data from the Oxford Survey of Childhood Cancers has shown that cases associated with foetal irradiation (X-rayed cases) accounted for a higher proportion of deaths between 5 and 10 years than of earlier or later deaths. This finding is compatible with somewhat later origins for the cancers actually caused by the radiation exposures (radiogenic cases) than for other (idiopathic) cases which proved fatal before 10 years of age. Therefore the usual time for incurring congenital anomalies (or the first trimester of foetal life) could be the commonest time for initiating childhood cancers. The theoretical implications of this and other findings of the Oxford Survey are discussed within the framework of a theory which assumes that all mutant cells have cancer potentialities and that defects in the immune surveillance mechanism favour multiplication of these cells (or endogenous sources of self-replicating foreign proteins) as well as live pathogens (or exogenous sources of self-replicating foreign proteins).
Plasma neurotrophin-3 (NT-3) levels are associated with several neural disorders. We previously reported that neurotrophins were released from salivary glands following acute immobilization stress. While the salivary glands were the source of plasma neurotrophins in that situation, the association between the expression of neurotrophins and the salivary gland under chronic stress conditions is not well understood. In the present study, we investigated whether NT-3 levels in the salivary gland and plasma were influenced by chronic stress.
Materials and Methods
Expressions of NT-3 mRNA and protein were characterized, using real-time polymerase chain reactions, enzyme-linked immunosorbent assay, and immunohistochemistry, in the submandibular glands of male rats exposed to chronic stress (12 h daily for 22 days).
Plasma NT-3 levels were significantly increased by chronic stress (p<0.05), and remained elevated in bilaterally sialoadenectomized rats under the same condition. Since chronic stress increases plasma NT-3 levels in the sialoadenectomized rat model, plasma NT-3 levels were not exclusively dependent on salivary glands.
While the salivary gland was identified in our previous study as the source of plasma neurotrophins during acute stress, the exposure to long-term stress likely affects a variety of organs capable of releasing NT-3 into the bloodstream. In addition, the elevation of plasma NT-3 levels may play important roles in homeostasis under stress conditions.
Chronic stress; NT-3; sialoadenectomized rat; submandibular gland
The data presented in this paper define the interrelationship between two endogenous diseases in the same host. The Haas strain of germfree mice with congenitally acquired persistent lymphocytic choriomeningitis (LCM) virus infection developed the X-ray-induced lymphatic leukemia independent of LCM viremia. The immunoproliferative LCM-related lesions appeared after age 7 months, and the radiogenic lymphatic leukemia appeared earlier or during the same age period. Both diseases evolved with distinctive lesions at the appropriate time, with no evidence of interference nor of synergism between the two syndromes. The Haas strain of mice showed an unusual sensitivity to X rays which was associated with depletion of blood components and coincident death. The sensitivity of the mice to X rays might be a characteristic of the Haas mouse or the result of an LCM virus-induced alteration in hematopoiesis.
Biologically motivated mathematical models are important for understanding the mechanisms of radiation-induced carcinogenesis. Existing models fall into two categories: (1) short-term formalisms, which focus on the processes taking place during and shortly after irradiation (effects of dose, radiation quality, dose rate and fractionation), and (2) long-term formalisms, which track background cancer risks throughout the entire lifetime (effects of age at exposure and time since exposure) but make relatively simplistic assumptions about radiation effects. Grafting long-term mechanisms on to short-term models is badly needed for modelling radiogenic cancer. A combined formalism was developed and applied to cancer risk data in atomic bomb survivors and radiotherapy patients and to background cancer incidence. The data for nine cancer types were described adequately with a set of biologically meaningful parameters for each cancer. These results suggest that the combined short–long-term approach is a potentially promising method for predicting radiogenic cancer risks and interpreting the underlying biological mechanisms.
Sjögren’s syndrome (SS) is a chronic autoimmune disease characterized by lymphocytic infiltration, destruction of lacrimal and salivary glands and the presence of serum autoantibodies. Most women that suffer from SS are post-menopausal however, not all post-menopausal women develop SS, suggesting that other factors, in addition to the decrease in ovarian hormones, are necessary for the development of SS. The purposes of this study were to investigate a) the time course of lymphocytic infiltration and apoptosis in the lacrimal gland after ovariectomy, b) if a predisposed genetic background for SS aggravates the effects of decreasing levels of sex hormones in the lacrimal glands and c) if physiological doses of estrogen or androgen prevent the effects observed after ovariectomy. Six weeks old mice that are genetically predisposed to SS (NOD.B10.H2b) and control (C57BL/10) mice were either sham-operated, ovariectomized (OVX), OVX + 17β estradiol (E2) or OVX + Dihydrotestosterone (DHT). Lacrimal glands were collected at 3, 7, 21 or 30 days after surgery and processed for immunohistochemistry to measure CD4+ , CD8+ T cells, B220+ B cells, nuclear DNA degradation and cleaved caspase-3 activity. Quantification of the staining was done by light microscopy and Image Pro Plus software. The results of our study show that lymphocytic infiltration preceded lacrimal gland apoptosis after ovariectomy. Moreover, removal of ovarian sex hormones accelerated these effects in the genetically predisposed animal and these effects were more severe and persistent compared to control animals. In addition, sex hormone replacement at physiological levels prevented these symptoms. The mechanisms by which decreased levels of sex hormones caused lymphocytic infiltration and apoptosis and the interaction of lack of sex hormones with the genetic elements remain to be elucidated.
lymphocytic infiltration; apoptosis; caspase 3; lacrimal gland; sjögren's syndrome; sex hormone; androgen; estrogen
Background & Aims
Excessive Ca2+ influx mediates many cytotoxic processes, including those associated with autoimmune inflammatory diseases such as acute pancreatitis and Sjögren's syndrome. TRPC3 is a major Ca2+ influx channel in pancreatic and salivary gland cells. We investigated whether genetic or pharmacological inhibition of TRPC3 protects pancreas and salivary glands from Ca2+-dependent damage.
We developed a Ca2+-dependent model of cell damage for salivary gland acini. Acute pancreatitis was induced by injection of cerulein into wild-type and Trpc3−/− mice. Mice were also given the Trpc3-selective inhibitor pyrazole 3 (Pyr3).
Salivary glands and pancreas of Trpc3−/− mice were protected from Ca2+-mediated cell toxicity. Analysis of Ca2+ signaling in wild-type and Trpc3−/− acini showed that Pyr3 is highly specific inhibitor of Tprc3; it protected salivary glands and pancreas cells from Ca2+-mediated toxicity by inhibiting the Trpc3-mediated component of Ca2+ influx.
TRPC3-mediated Ca2+ influx mediates damage to pancreas and salivary glands. Pharmacological inhibition of TRPC3 with the highly selective TRPC3 inhibitor Pyr3 might be developed for treatment of patients with acute pancreatitis and Sjögren's syndrome.
Ca2+ influx; inflammation; cell death; therapeutics
Clear cell changes may be observed in virtually any benign or malignant tumor of epithelial, mesenchymal, melanocytic and hematopoeitic derivation not be attributed to variable etiologies. In general, benign and malignant clear cell neoplasms of the head and neck are rare. They may involve various regions and may be of diverse derivations, with only 1–2% of tumors of the salivary glands, jaws and oral mucosa are primarily or almost exclusively composed of clear cells (Maiorano et al., Semin Diagn Pathol 14:203–212, 1997). This review will selectively discuss the clinicopathological features of salivary gland tumors with clear cell changes, which, at times, may pose a diagnostic challenge and dilemma.
Clear cell tumors; Head and neck; Salivary gland tumors