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1.  The Use of Stem Cells in Burn Wound Healing: A Review 
BioMed Research International  2015;2015:684084.
Burn wound healing involves a series of complex processes which are subject to intensive investigations to improve the outcomes, in particular, the healing time and the quality of the scar. Burn injuries, especially severe ones, are proving to have devastating effects on the affected patients. Stem cells have been recently applied in the field to promote superior healing of the wounds. Not only have stem cells been shown to promote better and faster healing of the burn wounds, but also they have decreased the inflammation levels with less scar progression and fibrosis. This review aims to highlight the beneficial therapeutic effect of stem cells in burn wound healing and to discuss the involved pathways and signaling molecules. The review covers various types of burn wound healing like skin and corneal burns, along with the alternative recent therapies being studied in the field of burn wound healing. The current reflection of the attitudes of people regarding the use of stem cells in burn wound healing is also stated.
PMCID: PMC4508388  PMID: 26236731
2.  Primary dermal fibroblasts derived from sdc-1 deficient mice migrate faster and have altered αv integrin function 
The goal of this study is to determine whether dermal fibroblasts lacking syndecan-1 (sdc1) show differences in integrin expression and function that could contribute to the delayed skin and corneal wound healing phenotypes seen in syndecan-1 (sdc-1) null mice. Using primary dermal fibroblasts, we show that after 3 days in culture no differences in α-smooth muscle actin were detected but sdc-1 null cells expressed significantly more αv and β1 integrin than wt cells. TGFβ1 treatment at day 3 increased αv- and β1- integrin expression in sdc-1 null cells at day 5 whereas wt cells showed increased expression only of αv-integrin. Using time-lapse studies, we showed that the sdc-1 null fibroblasts migrate faster than wt fibroblasts, treatment with TGFβ1 increased these migration differences, and treatment with a TGFβ1 antagonist caused sdc-1 null fibroblasts to slow down and migrate at the same rate as untreated wt cells. Cell spreading studies on replated fibroblasts showed altered cell spreading and focal adhesion formation on vitronectin and fibronectin coated surfaces. Additional time lapse studies with β1- and αv- integrin neutralizing antibodies, showed that wt fibroblasts expressing sdc-1 had activated integrins on their surface that impeded their migration whereas the null cells expressed αv-containing integrins which were less adhesive and enhanced cell migration. Surface expression studies showed increased surface expression of α2β1 and α3β1 on the sdc-1 null fibroblasts compared to wt fibroblasts but no significant differences in surface expression of α5β1, αvβ3, or αvβ5. Taken together, our data indicates that sdc-1 functions in the activation of αv-containing integrins and support the hypothesis that impaired wound healing phenotypes seen in sdc-1 null mice could be due to integrin-mediated defects in fibroblast migration after injury.
PMCID: PMC3664453  PMID: 19128260
integrins; fibroblasts; cell migration; syndecan-1
3.  Loss of syndecan-1 is associated with malignant conversion in skin carcinogenesis 
Molecular carcinogenesis  2010;49(4):363-373.
Syndecan-1 (sdc-1) is a cell surface proteoglycan that mediates the interaction of cells with their matrix, influencing attachment, migration and response to growth factors. In keratinocytes, loss of sdc-1 delays wound healing, reduces migration, and increases TGFβ1 expression. In this study we show that sdc-1 expression is significantly reduced in basal cell, squamous cell, and metastatic human skin cancers compared to normal human skin. In experimental mouse skin tumor induction, compared to wildtype (wt) BALB/c mice, papilloma formation in sdc-1 null mice was reduced by 50% and the percent of papillomas converting to squamous cell carcinoma (SCC) was enhanced. Sdc-1 expression on wildtype mouse papillomas decreased as they converted to SCC. Furthermore, papillomas forming on sdc-1 null mice expressed suprabasal α3 and β4 integrins; suprabasal β4 integrin is a marker of a high risk for progression. While the proliferative response to TPA did not differ among the genotypes, sdc-1 null mice had an enhanced inflammatory response and retained higher levels of total TGFβ1 within their skin after TPA treatment. Sdc-1 null keratinocytes, transduced in vitro by oncogenic rasHa, expressed higher levels of β4 integrin and had enhanced pSmad2 signaling and reduced senescence when compared to wildtype rasHa transduced keratinocytes. When rasHa transduced cells of both genotypes were grafted onto nude mice, null tumors converted to SCC with higher frequency confirming the skin painting experiments. These data indicate that sdc-1 is important both early in the development of skin tumors and in progression of skin cancers suggesting that reduced expression of sdc-1 could be a useful marker for progression in neoplastic skin lesions.
PMCID: PMC3653623  PMID: 20082322
skin carcinogenesis; keratinocytes; syndecan-1; integrin; laminin 332; TGFβ1; ras oncogene
4.  A Cell-Impermeable Cyclosporine A Derivative Reduces Pathology in a Mouse Model of Allergic Lung Inflammation 
Although the main regulators of leukocyte trafficking are chemokines, another family of chemotactic agents is cyclophilins. Intracellular cyclophilins function as peptidyl-protyl cis-trans isomerases and are targets of the immunosuppressive drug, cyclosporine A (CsA). Cyclophilins can also be secreted in response to stress factors, with elevated levels of extracellular cyclophilins detected in several inflammatory diseases. Extracellular cyclophilins are known to have potent chemotactic properties, suggesting they might contribute to inflammatory responses by recruiting leukocytes into tissues. The objective of the current study was to determine the impact of blocking cyclophilin activity using a cell-impermeable derivative of CsA, MM218, to specifically target extracellular pools of cyclophilins. We show that treatment with this compound in a mouse model of allergic lung inflammation: 1) demonstrates up to 80% reduction in inflammation, 2) directly inhibits the recruitment of antigen-specific CD4+ T cells, and 3) works equally well when delivered at 100-fold lower doses to the airways. Our findings suggest that cell-impermeable analogs of CsA can effectively reduce inflammatory responses by targeting leukocyte recruitment mediated by extracellular cyclophilins. Specifically blocking the extracellular function(s) of cyclophilins may provide a novel approach for inhibiting the recruitment of one of the principal immune regulators of allergic lung inflammation, antigen-specific CD4+ T cells, into inflamed airways and lungs.
PMCID: PMC3603141  PMID: 21057089
5.  Exposure to Particulate Hexavalent Chromium Exacerbates Allergic Asthma Pathology 
Airborne hexavalent chromate, Cr(VI), has been identified by the Environmental Protection Agency as a possible health threat in urban areas, due to the carcinogenic potential of some of its forms. Particulate chromates are produced in many different industrial settings, with high levels of aerosolized forms historically documented. Along with an increased risk of lung cancer, a high incidence of allergic asthma has been reported in workers exposed to certain inhaled particulate Cr(VI) compounds. However, a direct causal association between Cr(VI) and allergic asthma has not been established. We recently showed that inhaled particulate Cr(VI) induces an innate neutrophilic inflammatory response in BALB/c mice. In the current studies we investigated how the inflammation induced by inhaled particulate Cr(VI) might alter the pathology of an allergic asthmatic response. We used a well-established mouse model of allergic asthma. Groups of ovalbumin protein (OVA)-primed mice were challenged either with OVA alone, or with a combination of OVA and particulate zinc chromate, and various parameters associated with asthmatic responses were measured. Co-exposure to particulate Cr(VI) and OVA mediated a mixed form of asthma in which both eosinophils and neutrophils are present in airways, tissue pathology is markedly exacerbated, and airway hyperresponsiveness is significantly increased. Taken together these findings suggest that inhalation of particulate forms of Cr(VI) may augment the severity of ongoing allergic asthma, as well as alter its phenotype. Such findings may have implications for asthmatics in settings in which airborne particulate Cr(VI) compounds are present at high levels.
PMCID: PMC3288173  PMID: 22178736
hexavalent chromium; asthma; inflammation; lung
6.  Blocking Cyclophilins in the Chronic Phase of Asthma Reduces the Persistence of Leukocytes and Disease Reactivation 
Allergic asthma is characterized by acute influxes of proinflammatory leukocytes in response to allergen stimulation, followed by quiescent (chronic) periods between allergen challenges, during which sustained, low-level inflammation is evident. These chronic phases of disease are thought to be mediated by populations of leukocytes persisting within airways and tissues. The lack of any in situ proliferation by these cells, along with their limited lifespan, suggests that a continual recruitment of leukocytes from the circulation is needed to maintain disease chronicity. The mechanisms regulating this persistent recruitment of leukocytes are unknown. Although classic leukocyte-attracting chemokines are highly elevated after acute allergen challenge, they return to baseline levels within 24 hours, and remain close to undetectable during the chronic phase. In the present study, we investigated whether an alternative family of chemoattractants, namely, extracellular cyclophilins, might instead play a role in regulating the recruitment and persistence of leukocytes during chronic asthma, because their production is known to be more sustained during inflammatory responses. Using a new murine model of chronic allergic asthma, elevated concentrations of extracellular cyclophilin A, but not classic chemokines, were indeed detected during the chronic phase of asthma. Furthermore, blocking the activity of cyclophilins during this phase reduced the number of persisting leukocytes by up to 80%. This reduction was also associated with a significant inhibition of acute disease reactivation upon subsequent allergen challenge. These findings suggest that blocking the function of cyclophilins during the chronic phase of asthma may provide a novel therapeutic strategy for regulating disease chronicity and severity.
PMCID: PMC3262693  PMID: 21493785
chronic asthma; cyclophilins; cyclosporine A; NIM811
7.  Syndecan-1 Regulates Cell Migration and Fibronectin Fibril Assembly 
Experimental cell research  2010;316(14):2322-2339.
Corneal scarring is a major cause of blindness worldwide and can result from the deposition of abnormal amounts of collagen fibers lacking the correct size and spacing required to produce a clear cornea. Collagen fiber formation requires a preformed fibronectin (FN) matrix. We demonstrate that the loss of syndecan1 (sdc1) in corneal stromal cells (CSC) impacts cell migration rates, the sizes and composition of focal and fibrillar adhesions, the activation of integrins, and the assembly of fibronectin into fibrils. Integrin and fibronectin expression are not altered on sdc1 null CSCs. Cell adhesion, spreading, and migration studies using low compared to high concentrations of FN and collagen I (CNI) or vitronectin (VN) with and without activation of integrins by manganese chloride show that the impact of sdc1 depletion on integrin activation varies depending on the integrin-mediated activity evaluated. Differences in FN-fibrillogenesis and migration in sdc1 null CSCs are reversed by addition of manganese chloride but cell spreading differences remain. To determine if our findings on sdc1 were specific to the cornea, we compared the phenotypes of sdc1 null dermal fibroblasts with those of CSCs. We found that without sdc1, both cell types migrate faster; however, cell-type specific differences in FN expression and its assembly into fibrils exist between these two cell types. Together, our data demonstrate that sdc1 functions to regulate integrin activity in multiple cell types. Loss of sdc1-mediated integrin function results in cell-type specific differences in matrix assembly. A better understanding of how different cell types regulate FN fibril formation via syndecans and integrins will lead to better treatments for scarring and fibrosis.
PMCID: PMC3141227  PMID: 20580707
integrins; cell migration; fibronectin; corneal stromal cells
8.  BALB/c and C57BL6 mouse strains vary in their ability to heal corneal epithelial debridement wounds 
Experimental eye research  2008;87(5):478-486.
Genetically engineered mice are usually produced on a mixed genetic background and can be derived from several mouse strains including 129SvJ, C57BL6, and BALB/c. To determine whether differences in recurrent corneal epithelial erosions (RCEEs), corneal epithelial stem cell deficiency (CESCD), and cell migration rate vary between two different mouse strains (BALB/c and C57BL6), 8 week mice were subjected to 1.5 (small) or 2.8 mm (large) manual debridement wounds and allowed to heal for 4 weeks. Syndecan-1 (sdc-1) null mice backcrossed seven generations onto a BALB/c genetic background were also included in the RCEE and CESCD studies to permit comparisons between genotypes within a single strain. After sacrifice, corneas were assessed for the presence of recurrent erosions; no fewer than 15 corneas were used for each strain or genotype studied. Data show that the frequency of recurrent erosions after small wounds was 81 +/− 9% in the C57BL6 mice, 73 +/− 2% in the BALB/c mice, and 32 +/− 6% in sdc-1 null mice. Neither strain developed CESCD after small wounds. The frequency of erosions after large wounds was greater (88 +/− 8%) in the C57BL6 mice compared to BALB/c (60 +/− 2%), and sdc-1 null mice (32 +/− 5%). 4 weeks after the large wounds, fixed, flat mounted corneas were assessed for evidence of CESCD with antibodies against the conjunctival keratin K8 and the goblet cell marker, the mucin Muc5AC. The frequency of CESCD 4 weeks after the large wounds was significantly greater in the C57BL6 mice than in the BALB/c or sdc-1 null mice. To assess cell migration rates, corneas were subjected to 1.5 mm wounds and allowed to heal for 12, 15, 18, 21, and 24 hours. After sacrifice, corneas were stained with Richardson stain (BALB/c) or propidium iodide (C57BL6) to assess reepithelialization rates. While reepithelialization rates were similar for the early times after wounding, by 24 hours the C57BL6 corneas had healed faster: 16 of 30 corneas from the C57BL6 mice were closed compared to 9 of 30 of the BALB/c wounds. BALB/c corneas appeared larger overall compared to C57BL6 corneas; measurements of the overall mass of the enucleated eyes and diameters of the flat-mounted corneas confirmed that C57BL6 eyes and corneas were 6.8% and 4.4% smaller respectively than those of BALB/c mice even though the masses of the two mouse strains at 8 weeks of age were identical. Using BrdU to label dividing cells, we found that 18 hours after wounding, C57BL6 and BALB/c corneal epithelia showed similar numbers of proliferating cells. To determine if the enhanced corneal epithelial cell migration rate seen in the C57BL6 mice was specific to the cornea, we conducted time-lapse studies to assess random cell migration rates in vitro using primary cultures of mouse epidermal keratinocytes. Consistent with the in vivo data, epidermal keratinocytes derived from BALB/c mice migrated 60% slower than C57BL6 cells. These data prove that strain-specific differences in cell migration rate in vivo are present in the cornea and are accompanied by differences in the frequencies of recurrent erosions and corneal epithelial stem cell deficiency.
PMCID: PMC2654715  PMID: 18809399
9.  Inflammatory bowel disease in rats: Bacterial and chemical interaction 
AIM: To develop a novel model of colitis in rats, using a combination of iodoacetamide and enteropathogenic E. coli (EPEC), and to elucidate the pathophysiologic processes implicated in the development of ulcerative colitis (UC).
METHODS: Male Sprague-Dawley rats (n = 158) were inoculated intrarectally on a weekly basis with 4 different combinations: (a) 1% methylcellulose (MC), (b) 100 μL of 6% iodoacetamide (IA) in 1% MC, (c) 200 μL containing 4 × 108 colony factor units (CFU) of EPEC, and (d) combined treatment of (IA) followed by bacteria (B) after 2 d. Thirty days post treatment, each of the four groups was divided into two subgroups; the inoculation was stopped for one subgroup and the other subgroup continued with biweekly inoculation until the end of the experiment. Colitis was evaluated by the clinical course of the disease, the macroscopic and microscopic alterations, activity of myeloperoxidase (MPO), and by TNF-α gene expression.
RESULTS: Findings indicative of UC were seen in the combined treatment (IA + B) as well as the IA continued treatment groups: the animals showed slow rate of increase in body weight, diarrhea, bloody stools, high colonic ulcer score, as well as histological alterations characteristic of UC, with an extensive inflammatory reaction. During the course of the experiment, the MPO activity was consistently elevated and the TNF-α gene expression was upregulated compared to the control animals.
CONCLUSION: The experimental ulcerative colitis model used in the present study resembles, to a great extent, the human disease. It is reproducible with characteristics indicative of chronicity.
PMCID: PMC2725342  PMID: 18609687
Colitis; Escherichia coli; Iodoacetamide; Inflammatory bowel disease model; Gastrointestinal inflammation

Results 1-9 (9)