During spermatogenesis, mRNA localization and translation are believed to be regulated in a stage-specific manner. We report here that the Protamine2 (Prm2) mRNA transits through chromatoid bodies of round spermatids and localizes to cytosol of elongating spermatids for translation. The transacting factor CBF-A, also termed Hnrnpab, contributes to temporal regulation of Prm2 translation. We found that CBF-A co-localizes with the Prm2 mRNA during spermatogenesis, directly binding to the A2RE/RTS element in the 3′ UTR. Although both p37 and p42 CBF-A isoforms interacted with RTS, they associated with translationally repressed and de-repressed Prm2 mRNA, respectively. Only p42 was found to interact with the 5′cap complex, and to co-sediment with the Prm2 mRNA in polysomes. In CBF-A knockout mice, expression of protamine 2 (PRM2) was reduced and the Prm2 mRNA was prematurely translated in a subset of elongating spermatids. Moreover, a high percentage of sperm from the CBF-A knockout mouse showed abnormal DNA morphology. We suggest that CBF-A plays an important role in spermatogenesis by regulating stage-specific translation of testicular mRNAs.
During eukaryotic gene expression, a fraction of newly exported mRNA molecules is transported to the cellular periphery for translation. The underlying mechanisms are not fully understood even though they likely affect specialized functions in many cell types including oligodendrocyets, neurons and germ cells. We discovered that the heterogeneous nuclear ribonucleoprotein CBF-A, interacts with a conserved sequence, the RNA trafficking sequence (RTS), located in the untranslated region of transported mRNAs. This interaction facilitates transport of myelin basic protein mRNA and dendritic mRNAs in oligodendrocytes and neurons, respectively. Here we investigated whether RTS-recognition by CBF-A coordinates transport and localized translation of the Protamine 2 mRNA in spermatogenic cells. During spermatogenesis the Protamine 2 mRNAs is synthesized and kept in a silent form to be translated at later stages. We show that by interacting with the RTS of the Protamine 2 mRNA both CBF-A isoforms contribute to regulate the transcript at the translational level. In a CBF-A knockout mouse model, we demonstrate that the interplay between the CBF-A isoforms in translation regulation of the Protamine 2 mRNA and other testicular transcripts has an impact on spermatogenesis.
Intima-media thickness (IMT) provides a surrogate end point of cardiovascular outcomes in clinical trials evaluating the efficacy of cardiovascular risk factor modification. Carotid artery plaque further adds to the cardiovascular risk assessment. It is defined as a focal structure that encroaches into the arterial lumen of at least 0.5 mm or 50% of the surrounding IMT value or demonstrates a thickness >1.5 mm as measured from the media-adventitia interface to the intima-lumen interface. The scientific basis for use of IMT in clinical trials and practice includes ultrasound physics, technical and disease-related principles as well as best practice on the performance, interpretation and documentation of study results. Comparison of IMT results obtained from epidemiological and interventional studies around the world relies on harmonization on approaches to carotid image acquisition and analysis. This updated consensus document delineates further criteria to distinguish early atherosclerotic plaque formation from thickening of IMT. Standardized methods will foster homogenous data collection and analysis, improve the power of randomized clinical trials incorporating IMT and plaque measurements and facilitate the merging of large databases for meta-analyses. IMT results are applied to individual patients as an integrated assessment of cardiovascular risk factors. However, this document recommends against serial monitoring in individual patients.
Intima-media thickness; Carotid plaque; Vascular ultrasound; Randomized clinical trials; Carotid disease; Reference values
Intravascular clotting remains a major health problem in the United States, the most prominent being deep vein thrombosis, pulmonary embolism and thromboembolic stroke. Previous reports on the use of pyridine derivatives in cardiovascular drug development encourage us to pursue new types of compounds based on a pyridine scaffold. Eleven pyridine derivatives (oximes, semicarbazones, N-oxides) previously synthesized in our laboratories were tested as anticoagulants on pooled normal plasma using the prothrombin time (PT) protocol. The best anticoagulant within the oxime series was compound AF4, within the oxime N-oxide series was compound AF4-N-Oxide, and within the semicarbazone series, compound MD1-30Y. We also used a molecular modeling approach to guide our efforts, and found that there was good correlation between coagulation data and computational energy scores. Molecular docking was performed to target the active site of thrombin with the DOCK v5.2 package. The results of molecular modeling indicate that improvement in anticoagulant activities can be expected by functionalization at the 3-position of the pyridine ring and by N-oxide formation. Results reported here prove the suitability of DOCK in the lead optimization process.
pyridine oximes; pyridine semicarbazones; anticoagulants; molecular modeling; DOCK; thrombin
Changes in the uptake of many drugs by the target cells may dramatically affect the pharmacological response. Thus, downregulation of SLC22A1, which encodes the organic cation transporter type 1 (OCT1), may affect the response of healthy hepatocytes and liver cancer cells to cationic drugs, such as metformin and sorafenib, respectively. Moreover, the overall picture may be modified to a considerable extent by the preexistence or the appearance during the pathogenic process of genetic variants. Some rare OCT1 variants enhance transport activity, whereas other more frequent variants impair protein maturation, plasma membrane targeting or the function of this carrier, hence reducing intracellular active drug concentrations. Here, we review current knowledge of the role of OCT1 in modern liver pharmacology, which includes the use of cationic drugs to treat several diseases, some of them of great clinical relevance such as diabetes and primary liver cancer (cholangiocarcinoma and hepatocellular carcinoma). We conclude that modern pharmacology must consider the individual evaluation of OCT1 expression/function in the healthy liver and in the target tissue, particularly if this is a tumor, in order to predict the lack of response to cationic drugs and to be able to design individualized pharmacological treatments with the highest chances of success.
It has recently begun to be considered that cancer is a systemic disease and that it must be studied at every level of complexity using many of the currently available approaches, including high-throughput technologies and bioinformatics. To achieve such understanding in cervical cancer, we collected information on gene, protein and phosphoprotein expression of the HeLa cell line and performed a comprehensive analysis of the different signaling pathways, transcription networks and metabolic events in which they participate. A total expression analysis by RNA-Seq of the HeLa cell line showed that 19,974 genes were transcribed. Of these, 3,360 were over-expressed, and 2,129 under-expressed when compared to the NHEK cell line. A protein-protein interaction network was derived from the over-expressed genes and used to identify central elements and, together with the analysis of over-represented transcription factor motifs, to predict active signaling and regulatory pathways. This was further validated by Metal-Oxide Affinity Chromatography (MOAC) and Tandem Mass Spectrometry (MS/MS) assays which retrieved phosphorylated proteins. The 14-3-3 family members emerge as important regulators in carcinogenesis and as possible clinical targets. We observed that the different over- and under-regulated pathways in cervical cancer could be interrelated through elements that participate in crosstalks, therefore belong to what we term “meta-pathways”. Additionally, we highlighted the relations of each one of the differentially represented pathways to one or more of the ten hallmarks of cancer. These features could be maintained in many other types of cancer, regardless of mutations or genomic rearrangements, and favor their robustness, adaptations and the evasion of tissue control. Probably, this could explain why cancer cells are not eliminated by selective pressure and why therapy trials directed against molecular targets are not as effective as expected.
Primary cilia are cellular appendages important for signal transduction and sensing the environment. Bardet–Biedl syndrome proteins form a complex that is important for several cytoskeleton-related processes such as ciliogenesis, cell migration and division. However, the mechanisms by which BBS proteins may regulate the cytoskeleton remain unclear. We discovered that Bbs4- and Bbs6-deficient renal medullary cells display a characteristic behaviour comprising poor migration, adhesion and division with an inability to form lamellipodial and filopodial extensions. Moreover, fewer mutant cells were ciliated [48% ± 6 for wild-type (WT) cells versus 23% ± 7 for Bbs4 null cells; P < 0.0001] and their cilia were shorter (2.55 μm ± 0.41 for WT cells versus 2.16 μm ± 0.23 for Bbs4 null cells; P < 0.0001). While the microtubular cytoskeleton and cortical actin were intact, actin stress fibre formation was severely disrupted, forming abnormal apical stress fibre aggregates. Furthermore, we observed over-abundant focal adhesions (FAs) in Bbs4-, Bbs6- and Bbs8-deficient cells. In view of these findings and the role of RhoA in regulation of actin filament polymerization, we showed that RhoA-GTP levels were highly upregulated in the absence of Bbs proteins. Upon treatment of Bbs4-deficient cells with chemical inhibitors of RhoA, we were able to restore the cilia length and number as well as the integrity of the actin cytoskeleton. Together these findings indicate that Bbs proteins play a central role in the regulation of the actin cytoskeleton and control the cilia length through alteration of RhoA levels.
Major depressive disorder patients present chronic stress and decreased immunity. The Wistar-Kyoto rat (WKY) is a strain in which the hypothalamic-pituitary-adrenal axis is overactivated. To determine whether chronic stress induces changes in corticosterone levels and splenic lymphoid tissue, 9-week-old male rats were subject to restraint stress (3 h daily), chemical stress (hydrocortisone treatment, 50 mg/Kg weight), mixed stress (restraint plus hydrocortisone), or control treatment (without stress) for 1, 4, and 7 weeks. The serum corticosterone levels by RIA and spleens morphology were analyzed. Corticosterone levels as did the structure, size of the follicles and morphology of the parenchyma (increase in red pulp) in the spleen, varied depending on time and type of stressor. These changes indicate that chronic stress alters the immune response in the spleen in WKY rats by inducing morphological changes, explaining in part the impaired immunity that develops in organisms that are exposed to chronic stress.
Human immunodeficiency virus (HIV) has a small genome and therefore relies heavily on the host cellular machinery to replicate. Identifying which host proteins and complexes come into physical contact with the viral proteins is crucial for a comprehensive understanding of how HIV rewires the host’s cellular machinery during the course of infection. Here we report the use of affinity tagging and purification mass spectrometry1-3 to determine systematically the physical interactions of all 18 HIV-1 proteins and polyproteins with host proteins in two different human cell lines (HEK293 and Jurkat). Using a quantitative scoring system that we call MiST, we identified with high confidence 497 HIV–human protein–protein interactions involving 435 individual human proteins, with ~40% of the interactions being identified in both cell types. We found that the host proteins hijacked by HIV, especially those found interacting in both cell types, are highly conserved across primates. We uncovered a number of host complexes targeted by viral proteins, including the finding that HIV protease cleaves eIF3d, a subunit of eukaryotic translation initiation factor 3. This host protein is one of eleven identified in this analysis that act to inhibit HIV replication. This data set facilitates a more comprehensive and detailed understanding of how the host machinery is manipulated during the course of HIV infection.
Purpose. To report a case of severe corneal thinning secondary to dry eye treated with a tectonic Descemet stripping automated lamellar keratoplasty (DSAEK) and amniotic membrane graft. Methods. A 72-year-old man with a history of long standing diabetes mellitus type 2 and dry eye presented with 80% corneal thinning and edema on the right eye and no signs of infectious disease, initially managed with topical unpreserved lubrication and 20% autologous serum drops. Eight weeks after, the defect advanced in size and depth until Descemetocele was formed. Thereafter, he underwent DSAEK for tectonic purposes. One month after the procedure, the posterior lamellar graft was well adhered but a 4 mm epithelial defect was still present. A multilayered amniotic membrane graft was then performed. Results. Ocular surface healed quickly and reepithelization occurred over a 2-week period. Eight months after, the ocular surface remained stable and structurally adequate. Conclusion. Tectonic DSAEK in conjunction with multilayered amniotic graft may not only provide structural support and avoid corneal perforation, but may also promote reepithelization and ocular surface healing and decrease concomitant inflammation.
Vancomycin-resistant Enterococcus (VRE) endophthalmitis after penetrating keratoplasty (PKP) is very rare, the management is a challenge due to both the pattern of antibiotic resistance and the aggressive nature of the infectious process. We report the first delayed-onset case of VRE endophthalmitis after PKP.
Materials and Methods
Case report of a 51-year-old female with a 7-week history of PKP who arrived at the emergency room with signs and symptoms of endophthalmitis. Initial visual acuity was light perception, and a posterior pole exam was not possible due to the intense vitreous reaction. Mode B ultrasound was used to assess the posterior pole. The patient underwent pars plana vitrectomy and received intravitreous antibiotics.
Vitreous stains and cultures were positive for Enterococcus faecium resistant to vancomycin. Donor rim cultures and viral PCR were negative. Treatment was carried out by repeated intravitreal antibiotics and systemic linezolid. Clinical improvement was seen after the second dose of intravitreous antibiotics and systemic linezolid, but visual acuity remained at light perception consistent with the ischemic changes observed in the posterior pole.
VRE endophthalmitis might be associated with positive donor rim cultures. Prompt use of systemic linezolid in addition to intravitreous antibiotics is recommendable, but even with prompt treatment, visual prognosis is guarded.
Delayed-onset endophthalmitis; Penetrating keratoplasty; Vancomycin-resistant Enterococcus; Intravitreal antibiotics; Systemic linezolid
Background. It has been observed that African American race is associated with a lower prevalence of atrial fibrillation (AF) compared to Caucasian race. To better quantify the association between African American race and AF, we performed a meta-analysis of published studies among different patient populations which reported the presence of AF by race. Methods. A literature search was conducted using electronic databases between January 1999 and January 2011. The search was limited to published studies in English conducted in the United States, which clearly defined the presence of AF in African American and Caucasian subjects. A meta-analysis was performed with prevalence of AF as the primary endpoint. Results. In total, 10 studies involving 1,031,351 subjects were included. According to a random effects analysis, African American race was associated with a protective effect with regard to AF as compared to Caucasian race (odds ratio 0.51, 95% CI 0.44 to 0.59, P < 0.001). In subgroup analyses, African American race was significantly associated with a lower prevalence of AF in the general population, those hospitalized or greater than 60 years old, postcoronary artery bypass surgery patients, and subjects with heart failure. Conclusions. In a broad sweep of subjects in the general population and hospitalized patients, the prevalence of AF in African Americans is consistently lower than in Caucasians.
Human epidermal growth factor receptor 2 (HER2) expression in breast cancer is associated with an aggressive phenotype and poor prognosis, making it an appealing therapeutic target. Trastuzumab, an HER2 antibody-based inhibitor, is currently the leading targeted treatment for HER2+-breast cancers. Unfortunately, many patients inevitably develop resistance to the therapy, highlighting the need for alternative targeted therapeutic options. In this study, we used a novel, cell-based selection approach for isolating ‘cell-type specific’, ‘cell-internalizing RNA ligands (aptamers)’ capable of delivering therapeutic small interfering RNAs (siRNAs) to HER2-expressing breast cancer cells. RNA aptamers with the greatest specificity and internalization potential were covalently linked to siRNAs targeting the anti-apoptotic gene, Bcl-2. We demonstrate that, when applied to cells, the HER2 aptamer-Bcl-2 siRNA conjugates selectively internalize into HER2+-cells and silence Bcl-2 gene expression. Importantly, Bcl-2 silencing sensitizes these cells to chemotherapy (cisplatin) suggesting a potential new therapeutic approach for treating breast cancers with HER2+-status. In summary, we describe a novel cell-based selection methodology that enables the identification of cell-internalizing RNA aptamers for targeting therapeutic siRNAs to HER2-expressing breast cancer cells. The future refinement of this technology may promote the widespread use of RNA-based reagents for targeted therapeutic applications.
Transplanted individuals in operational tolerance (OT) maintain long-term stable graft function after completely stopping immunosuppression. Understanding the mechanisms involved in OT can provide valuable information about pathways to human transplantation tolerance. Here we report that operationally tolerant individuals display quantitative and functional preservation of the B-cell compartment in renal transplantation. OT exhibited normal numbers of circulating total B cells, naive, memory and regulatory B cells (Bregs) as well as preserved B-cell receptor repertoire, similar to healthy individuals. In addition, OT also displayed conserved capacity to activate the cluster of differentiation 40 (CD40)/signal transducer and activator of transcription 3 (STAT3) signaling pathway in Bregs, in contrast, with chronic rejection. Rather than expansion or higher activation, we show that the preservation of the B-cell compartment favors OT.
3MC syndrome has been proposed as a unifying term to integrate the overlapping Carnevale, Mingarelli, Malpuech and Michels syndromes. These rare autosomal recessive disorders of unknown cause comprise a spectrum of developmental features including characteristic facial dysmorphism, cleft lip and/or palate, craniosynostosis, learning disability, and genital, limb and vesicorenal anomalies. In a cohort of eleven 3MC families, we identified two mutated genes COLEC11 and MASP1 both of which encode proteins within the lectin complement pathway (CL-K1 and MASP-1 & −3 respectively). CL-K1 is highly expressed in embryonic murine craniofacial cartilage, heart, bronchi, kidney, and vertebral bodies. Zebrafish morphants develop pigment defects and severe craniofacial abnormalities.
Here, we show that CL-K1 serves as a key guidance cue for neural crest cell migration thus demonstrating for the first time, a role for complement pathway factors in fundamental developmental processes and the origin of 3MC syndrome.
The synaptonemal complex (SC) is a proteinaceous, meiosis-specific structure that is highly conserved in evolution. During meiosis, the SC mediates synapsis of homologous chromosomes. It is essential for proper recombination and segregation of homologous chromosomes, and therefore for genome haploidization. Mutations in human SC genes can cause infertility. In order to gain a better understanding of the process of SC assembly in a model system that would be relevant for humans, we are investigating meiosis in mice. Here, we report on a newly identified component of the murine SC, which we named SYCE3. SYCE3 is strongly conserved among mammals and localizes to the central element (CE) of the SC. By generating a Syce3 knockout mouse, we found that SYCE3 is required for fertility in both sexes. Loss of SYCE3 blocks synapsis initiation and results in meiotic arrest. In the absence of SYCE3, initiation of meiotic recombination appears to be normal, but its progression is severely impaired resulting in complete absence of MLH1 foci, which are presumed markers of crossovers in wild-type meiocytes. In the process of SC assembly, SYCE3 is required downstream of transverse filament protein SYCP1, but upstream of the other previously described CE–specific proteins. We conclude that SYCE3 enables chromosome loading of the other CE–specific proteins, which in turn would promote synapsis between homologous chromosomes.
Meiosis is a special type of cell division that takes place in the germ line of sexually reproducing diploid organisms. Major events during meiosis are the pairing, recombination, and segregation of homologous chromosomes. As a consequence, daughter cells are haploid and genetically diverse. Therefore, meiosis is of utmost importance for the life of sexually reproducing species as it maintains the species-specific chromosome number and generates genetic diversity within a species. Proper segregation of homologous chromosomes during meiosis requires homolog pairs to be physically linked. The synaptonemal complex (SC), a meiosis-specific structure conserved in evolution, is essential for this process. Defective assembly of the SC has deleterious effects on germ cells and can cause infertility in mice and humans. Here, we report on a newly identified protein component of the mammalian SC that we have named SYCE3. SYCE3 is strongly conserved among mammals. Using the mouse as a model system, we demonstrate that loss of SYCE3 leads to infertility in both sexes. Infertility is caused by disruption of meiosis due to the inability of Syce3−/− mice to assemble the central element of SCs. Our findings provide new insights into the complexity of SC assembly and its relevance to mammalian fertility.
The term vulnerability was first associated with the midbrain dopaminergic neurons 85 years ago, before they were identified as monoaminergic neurons, when Foix and Nicolesco (1925) reported the loss of neuromelanin containing neurons in the midbrain of patients with post-encephalitic Parkinson's disease (PD). A few years later, Hassler (1938) showed that degeneration is more intense in the ventral tier of the substantia nigra compacta than in its dorsal tier and the ventral tegmental area (VTA), outlining the concept of differential vulnerability of midbrain dopaminergic (DA-) neurons. Nowadays, we know that other neuronal groups degenerate in PD, but the massive loss of nigral DA-cells is its pathological hallmark, having a pivotal position in the pathophysiology of the disease as it is responsible for the motor symptoms. Data from humans as well as cellular and animal models indicate that DA-cell degeneration is a complex process, probably precipitated by the convergence of different risk factors, mediated by oxidative stress, and involving pathogenic factors arising within the DA-neuron (intrinsic factors), and from its environment and distant interconnected brain regions (extrinsic factors). In light of current data, intrinsic factors seem to be preferentially involved in the first steps of the degenerative process, and extrinsic factors in its progression. A controversial issue is the relative weight of the impairment of common cell functions, such as energy metabolism and proteostasis, and specific dopaminergic functions, such as pacemaking activity and DA handling, in the pathogenesis of DA-cell degeneration. Here we will review the current knowledge about the relevance of these factors at the beginning and during the progression of PD, and in the differential vulnerability of midbrain DA-cells.
Parkinson's disease; neurodegeneration; aging; differential vulnerability; nigrostriatal; mesolimbic; mitochondrion; proteostasis
Since 1989, we have been involved in the development of a vaccine against Haemophilus influenzae type b. The new vaccine is based on the conjugation of synthetic oligosaccharides to tetanus toxoid. Our main goals have been (i) to verify the feasibility of using the synthetic antigen and (ii) to search for new production alternatives for this important infant vaccine. Overall, eight trials have already been conducted with adults, children (4 to 5 years old), and infants. We have described herein the details from the first two phase I clinical trials conducted with human adult volunteers under double blind, randomized conditions. The participants each received a single intramuscular injection to evaluate safety and initial immunogenicity. We have found an excellent safety profile and an antibody response similar to the one observed for the control vaccine.
STUDY DESIGN—Cross sectional.
RESEARCH QUESTIONS—(a) Is any clinical variable of ankylosing spondylitis (AS) associated with the presence of ossification of the posterior longitudinal ligament (OPLL)? and (b) Is OPLL present in patients with AS from different geographical or genetic backgrounds?
METHODS—Three groups were assembled: (1) a prospective group of 103 consecutive AS patients from two community based rheumatology clinics from Guadalajara, who were evaluated using: a questionnaire with disease characteristic variables; clinical assessment by a neurologist; lateral radiographic views of the cervical spine and somatosensory evoked potentials (SSEP). (2) Fifty one spondyloarthropathies (SpA) patients from Mexico city whose cervical spine films were retrospectively reviewed. (3) Thirty nine AS patients from Edmonton, Canada whose cervical spine films were retrospectively reviewed and compared with 72 controls.
RESULTS—Group 1: 74% of the 103 patients were men and 86% were HLA-B27 positive. The mean age was 35 years, and mean (SD) disease duration 10 (8) years. OPLL was reported in 16 patients (15.5%; 95%C I 9, 22). OPLL was statistically associated with older age (p=0.001), longer disease duration (p=0.001), clinical myelopathy (p=0.03), worst functional index (p=0.042), restricted axial movement measurements (all p<0.001), radiological sacroiliitis (p<0.001 for linear association), osteitis pubis (p=0.009), hip involvement (p=0.006 for linear association), and abnormal SSEP (p=0.008). Group 2: 92% of 51 patients were men; the mean age was 30 years and the mean (SD) disease duration 11 (7) years. OPLL was reported in 15 (29%, 95%CI 17, 41) patients (nine AS, two psoriatic arthritis, three juvenile AS, and one Reiter's syndrome). Group 3: 95% of the 39 patients were men; the mean of age was 46 years and disease duration of 18 (10) years. OPLL was reported in nine (23%; 95%CI 10, 36) patients, including one with psoriatic arthritis, and two with Crohn's disease. OPLL was observed in two of the control group.
CONCLUSIONS—The prevalence of OPLL in AS and SpA is higher than previously recognised and seems to be associated with variables identifying more severe axial disease.
Keywords: ankylosing spondylitis; ossification of the posterior longitudinal ligament; psoriatic arthritis; Reiter's syndrome
AIM: To investigate the correlation between preoperative measurement in total knee arthroplasty and the prosthetic size implanted.
METHODS: A prospective double-blind study of 50 arthroplasties was performed. Firstly, the reliability and correspondence between the size of said measurement and the actual implant utilized was determined. Secondly, the existing correlation between the intra- and interobserver determinations with the intraclass correlation coefficient was analyzed.
RESULTS: An overall correspondence of 54%, improving up to 92% when the measured size admitted a difference of one size, was found. Good intra- and interobserver reliability with an intraclass correlation coefficient greater than 0.90 (P < 0.001) was also discovered.
CONCLUSION: Agreement between the preoperative measurement with standardized acetate templates and the prosthetic size implanted can be considered satisfactory. We thus conclude it is a reproducible technique.
Total knee arthroplasty; Templating; Preoperative measurement; Prosthetic size; Correlation coefficient
Alzheimer’s disease (AD) and other dementias are likely preceded by a protracted preclinical state. Thus, identification of biomarkers that signal potential points of intervention during this prodromal phase (during which patients are largely able to compensate for their cognitive deficits) is of paramount importance. Insulin is a pancreatic hormone with potent central nervous system effects, and insulin dysregulation has been implicated in the pathogenesis of both AD and vascular dementia. The aim of the current study was to determine whether circulating insulin differs as a function of mild cognitive impairment (MCI) diagnosis, and whether this relationship is mediated by sex and apolipoprotein E (APOE) genotype. A sample of 549 nondemented participants aged 65 and over from the Adult Changes in Thought community-based cohort underwent cognitive testing and blood draw to determine fasting levels of plasma insulin. Subjects were categorized as having normal cognitive functioning, amnestic MCI, or nonamnestic MCI. Results showed that the relationship between insulin and diagnostic category is moderated by sex, such that men with nonamnestic or amnestic MCI have higher fasting plasma insulin than cognitively normal men, while women with amnestic MCI have lower fasting plasma insulin than cognitively normal women. Exploratory analyses suggest that APOE ε4 genotype may further influence the relationship between sex and insulin. Future research will help determine whether insulin dysregulation results in differential effects on vascular function and AD pathology as a function of sex and/or APOE genotype.
Age-related memory disorders; aging; Alzheimer’s disease; cognition; dementia; hyperinsulinemia; insulin; vascular
Bacterial manganese (Mn) oxidation plays an important role in the global biogeochemical cycling of Mn and other compounds, and the diversity and prevalence of Mn oxidizers have been well established. Despite many hypotheses of why these bacteria may oxidize Mn, the physiological reasons remain elusive. Intracellular Mn levels were determined for Pseudomonas putida GB-1 grown in the presence or absence of Mn by inductively coupled plasma mass spectrometry (ICP-MS). Mn oxidizing wild type P. putida GB-1 had higher intracellular Mn than non Mn oxidizing mutants grown under the same conditions. P. putida GB-1 had a 5 fold increase in intracellular Mn compared to the non Mn oxidizing mutant P. putida GB-1-007 and a 59 fold increase in intracellular Mn compared to P. putida GB-1 ∆2665 ∆2447. The intracellular Mn is primarily associated with the less than 3 kDa fraction, suggesting it is not bound to protein. Protein oxidation levels in Mn oxidizing and non oxidizing cultures were relatively similar, yet Mn oxidation did increase survival of P. putida GB-1 when oxidatively stressed. This study is the first to link Mn oxidation to Mn homeostasis and oxidative stress protection.