miR-146a Decreases Inflammation and ROS Production in Aged Dermal Fibroblasts.

Aging is associated with a decline in the functionality of various cell types, including dermal fibroblasts, which play a crucial role in maintaining skin homeostasis and wound healing. Chronic inflammation and increased reactive oxygen species (ROS) production are hallmark features of aging, contributing to impaired wound healing. MicroRNA-146a (miR-146a) has been implicated as a critical regulator of inflammation and oxidative stress in different cell types, yet its role in aged dermal fibroblasts and its potential relevance to wound healing remains poorly understood. We hypothesize that miR-146a is differentially expressed in aged dermal fibroblasts and that overexpression of miR-146a will decrease aging-induced inflammatory responses and ROS production. Primary dermal fibroblasts were isolated from the skin of 17-week-old (young) and 88-week-old (aged) mice. Overexpression of miR-146a was achieved through miR-146a mimic transfection. ROS were detected using a reliable fluorogenic marker, 2,7-dichlorofluorescin diacetate. Real-time PCR was used to quantify relative gene expression. Our investigation revealed a significant reduction in miR-146a expression in aged dermal fibroblasts compared to their younger counterparts. Moreover, aged dermal fibroblasts exhibited heightened levels of inflammatory responses and increased ROS production. Importantly, the overexpression of miR-146a through miR-146a mimic transfection led to a substantial reduction in inflammatory responses through modulation of the NF-kB pathway in aged dermal fibroblasts. Additionally, the overexpression of miR-146a led to a substantial decrease in ROS production, achieved through the downregulation of NOX4 expression in aged dermal fibroblasts. These findings underscore the pivotal role of miR-146a in mitigating both inflammatory responses and ROS production in aged dermal fibroblasts, highlighting its potential as a therapeutic target for addressing age-related skin wound healing.

LincRNA-EPS Promotes Proliferation of Aged Dermal Fibroblast by Inducing CCND1.

The aging process is linked to numerous cellular changes, among which are modifications in the functionality of dermal fibroblasts. These fibroblasts play a crucial role in sustaining the healing of skin wounds. Reduced cell proliferation is a hallmark feature of aged dermal fibroblasts. Long intergenic non-coding RNA (lincRNAs), such as LincRNA-EPS (Erythroid ProSurvival), has been implicated in various cellular processes. However, its role in aged dermal fibroblasts and its impact on the cell cycle and its regulator, Cyclin D1 (CCND1), remains unclear. Primary dermal fibroblasts were isolated from the skin of 17-week-old (young) and 88-week-old (aged) mice. Overexpression of LincRNA-EPS was achieved through plasmid transfection. Cell proliferation was detected using the MTT assay. Real-time PCR was used to quantify relative gene expressions. Our findings indicate a noteworthy decline in the expression of LincRNA-EPS in aged dermal fibroblasts, accompanied by reduced levels of CCND1 and diminished cell proliferation in these aging cells. Significantly, the overexpression of LincRNA-EPS in aged dermal fibroblasts resulted in an upregulation of CCND1 expression and a substantial increase in cell proliferation. Mechanistically, LincRNA-EPS induces CCND1 expression by sequestering miR-34a, which was dysregulated in aged dermal fibroblasts, and directly targeting CCND1. These outcomes underscore the crucial role of LincRNA-EPS in regulating CCND1 and promoting cell proliferation in aged dermal fibroblasts. Our study provides novel insights into the molecular mechanisms underlying age-related changes in dermal fibroblasts and their implications for skin wound healing. The significant reduction in LincRNA-EPS expression in aged dermal fibroblasts and its ability to induce CCND1 expression and enhance cell proliferation highlight its potential as a therapeutic target for addressing age-related skin wound healing.

Discovery of Small Molecule Activators of Chemokine Receptor CXCR4 That Improve Diabetic Wound Healing.

Diabetes produces a chronic inflammatory state that contributes to the development of vascular disease and impaired wound healing. Despite the known individual and societal impacts of diabetic ulcers, there are limited therapies effective at improving healing. Stromal cell-derived factor 1α (SDF-1α) is a CXC chemokine that functions via activation of the CXC chemokine receptor type 4 (CXCR4) receptor to recruit hematopoietic cells to locations of tissue injury and promote tissue repair. The expression of SDF-1α is reduced in diabetic wounds, suggesting a potential contribution to wound healing impairment and presenting the CXCR4 receptor as a target for therapeutic investigations. We developed a high-throughput ß-arrestin recruitment assay and conducted structure-activity relationship (SAR) studies to screen compounds for utility as CXCR4 agonists. We identified CXCR4 agonist UCUF-728 from our studies and further validated its activity in vitro in diabetic fibroblasts. UCUF-728 reduced overexpression of miRNA-15b and miRNA-29a, negative regulators of angiogenesis and type I collagen production, respectively, in diabetic fibroblasts. In vivo, UCUF-728 reduced the wound closure time by 36% and increased the evidence of angiogenesis in diabetic mice. Together, this work demonstrates the clinical potential of small molecule CXCR4 agonists as novel therapies for pathologic wound healing in diabetes.

Cerium oxide nanoparticle delivery of microRNA-146a for local treatment of acute lung injury.

Acute respiratory distress syndrome (ARDS) is a devastating pulmonary disease with significant in-hospital mortality and is the leading cause of death in COVID-19 patients. Excessive leukocyte recruitment, unregulated inflammation, and resultant fibrosis contribute to poor ARDS outcomes. Nanoparticle technology with cerium oxide nanoparticles (CNP) offers a mechanism by which unstable therapeutics such as the anti-inflammatory microRNA-146a can be locally delivered to the injured lung without systemic uptake. In this study, we evaluated the potential of the radical scavenging CNP conjugated to microRNA-146a (termed CNP-miR146a) in preventing acute lung injury (ALI) following exposure to bleomycin. We have found that intratracheal delivery of CNP-miR146a increases pulmonary levels of miR146a without systemic increases, and prevents ALI by altering leukocyte recruitment, reducing inflammation and oxidative stress, and decreasing collagen deposition, ultimately improving pulmonary biomechanics.

LncRNA MALAT1 Modulates TGF-ß1-Induced EMT in Keratinocyte.

One of the major complications in diabetes is impaired wound healing. Unfortunately, effective therapies are currently lacking. Epithelial to mesenchymal transition (EMT) is a critical process involved in cutaneous wound healing. In response to injury, EMT is required to activate and mobilize stationary keratinocytes in the skin toward the wound bed, which allows for re-epithelialization. This process is stalled in diabetic wounds. In this study, we investigate the role of long non-coding RNA (lncRNA), MALAT1, in transforming growth factor beta 1(TGF-ß1)-induced EMT of human keratinocyte (HaCaT) cells. Initially, we detected MALAT1 and TGF-ß1 expression in non-diabetic and diabetic wounds and found that these expression are significantly up-regulated in diabetic wounds. Then, HaCaT cells were cultured and exposed to TGF-ß1. The EMT of HaCaT cells were confirmed by the increased expression of CDH2, KRT10, and ACTA2, in addition to the down-regulation of CDH1. Knockdown of MALAT1 was achieved by transfecting a small interfering RNA (SiRNA). MALAT1 silencing attenuates TGFß1-induced EMT. Mechanistically, MALAT1 is involved in TGF-ß1 mediated EMT through significantly induced ZEB1 expression, a critical transcription factor for EMT. In summary, lncRNA MALAT1 is involved in TGFß1-induced EMT of human HaCaT cells and provides new understanding for the pathogenesis of diabetic wounds.

Role of microRNA-21 and Its Underlying Mechanisms in Inflammatory Responses in Diabetic Wounds.

A central feature of diabetic wounds is the persistence of chronic inflammation, which is partly due to the prolonged presence of pro-inflammatory (M1) macrophages in diabetic wounds. Persistence of the M1 macrophage phenotype and failure to transition to the regenerative or pro-remodeling (M2) macrophage phenotype plays an indispensable role in diabetic wound impairment; however, the mechanism underlying this relationship remains unclear. Recently, microRNAs have been shown to provide an additional layer of regulation of gene expression. In particular, microRNA-21 (miR-21) is essential for an inflammatory immune response. We hypothesize that miR-21 plays a role in regulating inflammation by promoting M1 macrophage polarization and the production of reactive oxygen species (ROS). To test our hypothesis, we employed an in vivo mouse skin wound model in conjunction with an in vitro mouse model to assess miR-21 expression and macrophage polarization. First, we found that miR-21 exhibits a distinct expression pattern in each phase of healing in diabetic wounds. MiR-21 abundance was higher during early and late phases of wound repair in diabetic wounds, while it was significantly lower in the middle phase of wounding (at days 3 and 7 following wounding). In macrophage cells, M1 polarized macrophages exhibited an upregulation of miR-21, as well as the M1 and pro-inflammatory markers IL-1b, TNFa, iNos, IL-6, and IL-8. Overexpression of miR-21 in macrophage cells resulted in an upregulation of miR-21 and also increased expression of the M1 markers IL-1b, TNFa, iNos, and IL-6. Furthermore, hyperglycemia induced NOX2 expression and ROS production through the HG/miR-21/PI3K/NOX2/ROS signaling cascade. These findings provide evidence that miR-21 is involved in the regulation of inflammation. Dysregulation of miR-21 may explain the abnormal inflammation and persistent M1 macrophage polarization seen in diabetic wounds.

Use of oral contraceptives and risk of ulcerative colitis - A systematic review and meta-analysis.

Numerous studies have investigated the link between oral contraceptives and risk of ulcerative colitis (UC), but the results have been controversial. We systematically reviewed all relevant published studies and evaluated the association between the use of oral contraceptives and the development of UC by meta-analysis. Databases including PubMed, EMbase, CNKI and WanFang data were thoroughly searched from inception to September 2018 to collect the studies on the correlation between oral contraceptives and the risk of UC. The studies were screened according to the inclusion and exclusion criteria by two researchers independently, and the data were extracted and the quality was evaluated. Meta-analysis was performed using Stata 13.0 software. There were 12 studies involving 303,340 participants that reported on the association between oral contraceptives and UC. The pooled odds ratio (OR) of UC in oral contraceptive users was 1.25 [95% confidence interval (CI) 1.04-1.51, p = 0.02]. The risk was significant in the current oral contraceptive users (OR 1.49, 95% CI 1.12-1.96, p = 0.005) whereas the past oral contraceptive use was not significantly associated with UC (OR 1.17, 95% CI 0.95-1.43, p = 0.141). This study provides evidence of an association between the use of oral contraceptives and the onset risk of UC. The study also shows that the risk for patients who stop using the oral contraceptives was decreased. These findings may be used as important reference for the use of oral contraceptives and the management of UC patients.

Mesenchymal stem cells correct impaired diabetic wound healing by decreasing ECM proteolysis.

Impaired diabetic wound healing is associated with a dermal extracellular matrix protein profile favoring proteolysis; within the healing diabetic wound, this is represented by an increase in activated matrix metalloproteinase (MMPs). Treatment of diabetic wounds with mesenchymal stem cells (MSCs) has been shown to improve wound healing; however, there has not yet been an assessment of their ability to correct dysregulation of MMPs in diabetic wounds. Furthermore, there has been no prior assessment of the role of microRNA29b (miR-29b), an inhibitory regulatory molecule that targets MMP-9 mRNA. Using in vitro models of fibroblast coculture with MSCs and in vivo murine wound healing models, we tested the hypothesis that MSCs correct dysregulation of MMPs in a microRNA-29b-dependent mechanism. In this study, we first demonstrated that collagen I and III protein content is significantly reduced in diabetic wounds, and treatment with MSCs significantly improves collagen I content in both nondiabetic and diabetic wounds. We then found that MMP-9 gene expression and protein content were significantly upregulated in diabetic wounds, indicating elevated proteolysis. Treatment with MSCs resulted in a decrease in MMP-9 gene expression and protein content level in diabetic wounds 3 and 7 days after wounding. Zymographic analysis indicated that MSC treatment also decreased the amount of activated MMP-9 present in diabetic wounds. Furthermore, miR-29b expression was inversely associated with MMP-9 gene expression; miR-29b expression was decreased in diabetic wounds and diabetic fibroblast. Following treatment of diabetic wounds with MSCs, as well as in diabetic fibroblasts cocultured with MSCs, miR-29b was significantly increased. These findings suggest a potential mechanism through which MSCs enhance diabetic wound healing by improving collagen I content in diabetic wounds through decreasing MMP-9 expression and increasing miR-29b expression.

Mechanisms of mesenchymal stem cell correction of the impaired biomechanical properties of diabetic skin: The role of miR-29a.

Diabetic skin has impaired wound healing properties following injury. We have further shown that diabetic skin has weakened biomechanical properties at baseline. We hypothesize that the biomechanical properties of diabetic skin decline during the progression of the diabetic phenotype, and that this decline is due to the dysregulation of miR-29a, resulting in decreased collagen content. We further hypothesize that treatment with mesenchymal stem cells (MSCs) may improve diabetic wound healing by correction of the dysregulated miR-29a expression. We analyzed the biomechanical properties, collagen gene expression, collagen protein production, and miR-29a levels in skin harvested from 6 to 18 week old mice during the development of the diabetic phenotype. We also examined the correction of these impairments by both MSC treatment and the inhibition of miR-29a. Diabetic skin demonstrated a progressive impairment of biomechanical properties, decreased collagen content, and increased miR-29a levels during the development of the diabetic phenotype. MSC treatment decreased miR-29a levels, increased collagen content, and corrected the impaired biomechanical properties of diabetic skin. Additionally, direct inhibition of miR-29a also increased collagen content in diabetic skin. This decline in the biomechanical properties of diabetic skin during the progression of diabetes may increase the susceptibility of diabetic skin to injury and miR-29a appears to play a key role in this process.

SCF increases in utero-labeled stem cells migration and improves wound healing.

Diabetic skin wounds lack the ability to heal properly and constitute a major and significant complication of diabetes. Nontraumatic lower extremity amputations are the number one complication of diabetic skin wounds. The complexity of their pathophysiology requires an intervention at many levels to enhance healing and wound closure. Stem cells are a promising treatment for diabetic skin wounds as they have the ability to correct abnormal healing. Stem cell factor (SCF), a chemokine expressed in the skin, can induce stem cells migration, however the role of SCF in diabetic skin wound healing is still unknown. We hypothesize that SCF would correct the impairment and promote the healing of diabetic skin wounds. Our results show that SCF improved wound closure in diabetic mice and increased HIF-1α and vascular endothelial growth factor (VEGF) expression levels in these wounds. SCF treatment also enhanced the migration of red fluorescent protein (RFP)-labeled skin stem cells via in utero intra-amniotic injection of lenti-RFP at E8. Interestingly these RFP+ cells are present in the epidermis, stain negative for K15, and appear to be distinct from the already known hair follicle stem cells. These results demonstrate that SCF improves diabetic wound healing in part by increasing the recruitment of a unique stem cell population present in the skin.

The role of microRNA-15b in the impaired angiogenesis in diabetic wounds.

The impairment in diabetic wound healing represents a significant clinical problem. Decreased angiogenesis is thought to play a central role in the pathogenesis of this impairment. We have previously shown that treatment of diabetic murine wounds with mesenchymal stem cells can improve healing, but the mechanisms are not completely defined. MicroRNA-15b (miR-15b) has been implicated in the regulation of the angiogenic response. We hypothesized that abnormal miR-15b expression may contribute to the impaired angiogenesis observed in impaired diabetic wound healing. To test this hypothesis, we examined the expression of miR-15b and its target genes in diabetic and nondiabetic mice before and after injury. MiR-15b expression was significantly up-regulated in diabetic mouse wounds during the wound healing response. Increased miR-15b levels also closely correlated with decreased gene expression of its proangiogenic target genes. Furthermore, the correction of the diabetic wound healing impairment with mesenchymal stem cell treatment was associated with a significant decrease in miR-15b expression level and increased gene expression of its proangiogenic target genes. These results provide the first evidence that increased expression of miR-15b in diabetic wounds in response to injury may, in part, be responsible for the abnormal angiogenic response seen in diabetic wounds and may contribute to the observed wound healing impairment.

Modulation of the inflammatory response by increasing fetal wound size or interleukin-10 overexpression determines wound phenotype and scar formation.

Wound size impacts the threshold between scarless regeneration and reparative healing in the fetus with increased inflammation showed in fetal scar formation. We hypothesized that increased fetal wound size increases pro-inflammatory and fibrotic genes with resultant inflammation and fibroplasia and that transition to scar formation could be reversed by overexpression of interleukin-10 (IL-10). To test this hypothesis, 2-mm and 8-mm dermal wounds were created in mid-gestation fetal sheep. A subset of 8-mm wounds were injected with a lentiviral vector containing the IL-10 transgene (n = 4) or vehicle (n = 4). Wounds were harvested at 3 or 30 days for histology, immunohistochemistry, analysis of gene expression by microarray, and validation with real-time polymerase chain reaction. In contrast to the scarless 2-mm wounds, 8-mm wounds showed scar formation with a differential gene expression profile, increased inflammatory cytokines, decreased CD45+ cells, and subsequent inflammation. Lentiviral-mediated overexpression of the IL-10 gene resulted in conversion to a regenerative phenotype with decreased inflammatory cytokines and regeneration of dermal architecture. In conclusion, increased fetal wounds size leads to a unique gene expression profile that promotes inflammation and leads to scar formation and furthermore, these results show the significance of attenuated inflammation and IL-10 in the transition from fibroplasia to fetal regenerative healing.

Dysregulation of collagen production in diabetes following recurrent skin injury: contribution to the development of a chronic wound.

Recurrent injury has been implicated in the development of chronic diabetic wounds. We have developed a chronic diabetic wound model based upon recurrent injury in diabetic mice. We hypothesized that dysregulation of collagen production at both the mRNA and microRNA levels contributes to the development of chronic diabetic wounds. To test this, both diabetic and nondiabetic mice were made to undergo recurrent injury. Real-time PCR for TGF-ß1, SMAD-3, Col1α1, Col3α1, microRNA-25, and microRNA-29a and Western blot for collagen I and III were performed 7 days following each injury. Diabetic wounds displayed decreased collagen at all time points. This was associated with dysregulated collagen production at both the gene and microRNA levels at all time points. Following the final injury, however, diabetic collagen production significantly improved. This appeared to be due to a substantial decrease in both microRNAs as well as an increase in the expression of collagen pathway genes. That dysregulated collagen production progressed throughout the course of wounding suggests that this is one factor contributing to the development of chronic diabetic wounds. Future studies using this model will allow for the determination of other factors that may also contribute to the development and/or persistence of chronic diabetic wounds.

Lentiviral-mediated over-expression of hyaluronan synthase-1 (HAS-1) decreases the cellular inflammatory response and results in regenerative wound repair.

Fetal wounds have been found to have increased levels of high-molecular-weight hyaluronan (HMW-HA) compared with those of adults. The primary enzyme responsible for producing HMW-HA is hyaluronic acid synthase-1 (HAS-1). We hypothesized that over-expression of HAS-1 in adult dermal wounds would decrease inflammation and promote regenerative healing. To test this hypothesis, the flanks of adult C57Bl/6 mice were treated with a lentiviral construct containing either HAS-1-GFP or GFP transgenes. After 48 h, a 4-mm excisional wound was made at the site of treatment. Wounds were harvested at days 3, 7, or 28 after wounding. Wound phenotype was assessed by histology to examine tissue architecture and immunohistochemistry for CD45. At 7 and 28 days, lenti-HAS-1-treated wounds demonstrated the restoration of the normal dermal elements and organized collagen fiber orientation. In contrast, the lenti-GFP-treated wounds lacked normal dermal architecture and demonstrated a disorganized collagen scar. At 3 and 7 days, wounds treated with lenti-HAS-1 exhibited a significant decrease in the number of inflammatory cells when compared with wounds treated with lenti-GFP. Thus, HAS-1 over-expression promotes dermal regeneration, in part by decreasing the inflammatory response and by recapitulation of fetal extracellular matrix HMW-HA content.

Predictive Accuracy Comparison of Prognostic Scoring Systems for Survival in Patients Undergoing TIPS Placement: A Systematic Review and Meta-analysis.

RATIONALE AND OBJECTIVES: This meta-analysis aimed to evaluate the performance of different risk assessment models (RAMs) for survival after Transjugular Intrahepatic Portosystemic Shunt (TIPS) in patients with cirrhotic portal hypertension. MATERIALS AND METHODS: A systematic search of PubMed, WOS, Embase, Cochrane, and CNKI from inception to February 2023 was conducted. We comprehensively reviewed and aggregated data from numerous studies covering prevalent RAMs such as Child-Turcotte-Pugh, the Model for End-Stage Liver Disease (MELD), MELD-Sodium (MELD-Na), the Freiburg Index of Post-TIPS Survival (FIPS), Bilirubin-platelet, Chronic Liver Failure Consortium Acute Decompensation score, and Albumin-Bilirubin grade across different timeframes. For this study, short-term is defined as outcomes within a year while long-term refers to outcomes beyond one year. The area under the receiver operating characteristic (AUC) curve or Concordance Statistics was chosen as the metric to assess predictive capacity for mortality outcomes across six predetermined time intervals. Mean effect sizes at various time points were determined using robust variance estimation. RESULTS: MELD consistently stood out as a primary short-term survival predictor, particularly for 1 month (± 2 weeks) (AUC: 0.72) and 3 months of (± 1 month) survival (AUC: 0.72). MELD-Na showed the best long-term predictive ability, with an AUC of 0.70 at 3.5 years (± 1.5 years). FIPS performed well for 6 months of (± 2 months) survival (AUC: 0.68) and overall transplant-free survival (AUC: 0.75). Efficacy nuances were observed in RAMs when applied to particular subgroups. Meta-regression emphasized the potential predictor overlaps in models like MELD and FIPS. CONCLUSION: This meta-analysis underscores the MELD score as the premier predictor for short-term survival following TIPS. Meanwhile, the FIPS score and MELD-Na model exhibit potential in forecasting long-term outcomes. The study accentuates the significance of RAM selection for enhancing patient outcomes and advocates for additional research to corroborate these findings and fine-tune risk assessment in TIPS.

LncRNA MALAT1 Regulates Hyperglycemia Induced EMT in Keratinocyte via miR-205.

Epithelial-to-mesenchymal transition (EMT) is critical to cutaneous wound healing. When skin is injured, EMT activates and mobilizes keratinocytes toward the wound bed, therefore enabling re-epithelialization. This process becomes dysregulated in patients with diabetes mellitus (DM). Long non-coding RNAs (lncRNAs) regulate many biological processes. LncRNA-metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) influences numerous cellular processes, including EMT. The objective of the current study is to explore the role of MALAT1 in hyperglycemia (HG)-induced EMT. The expression of MALAT1 was found to be significantly upregulated, while the expression of miR-205 was downregulated in diabetic wounds and high-glucose-treated HaCaT cells. The initiation of EMT in HaCaT cells from hyperglycemia was confirmed by a morphological change, the increased expression of CDH2, KRT10, and ACTA2, and the downregulation of CDH1. The knockdown of MALAT1 was achieved by transfecting a small interfering RNA (SiRNA). MALAT1 and miR-205 were found to modulate HG-induced EMT. MALAT1 silencing or miR-205 overexpression appears to attenuate hyperglycemia-induced EMT. Mechanistically, MALAT1 affects HG-induced EMT through binding to miR-205 and therefore inducing ZEB1, a critical transcription factor for EMT. In summary, lncRNA MALAT1 is involved in the hyperglycemia-induced EMT of human HaCaT cells. This provides a new perspective on the pathogenesis of diabetic wounds.

Triazolothiadiazine derivative positively modulates CXCR4 signaling and improves diabetic wound healing.

Development of specific therapies that target and accelerate diabetic wound repair is an urgent need to alleviate pain and suffering and the huge socioeconomic burden of this debilitating disease. C-X-C Motif Chemokine Ligand 12 (CXCL12) also know an stromal cell-derived factor 1α (SDF-1α) is a chemokine that binds the CXC chemokine receptor type 4 (CXCR4) and activates downstream signaling resulting in recruitment of hematopoietic cells to locations of tissue injury and promotes tissue repair. In diabetes, low expression of CXCL12 correlates with impaired wound healing. Activation of CXCR4 receptor signaling with agonists or positive allosteric modulators (PAMs) provides a potential for small molecule therapeutic discovery and development. We recently reported high throughput screening and identification of the CXCR4 partial agonist UCUF-728, characterization of in vitro activity and reduced wound closure time in diabetic mice at 100 µM as a proof-of-concept study. We report here, the discovery of a second chemical scaffold demonstrating increased agonist potency and represented by thiadiazine derivative, UCUF-965. UCUF-965 is a potent partial agonist of ß-arrestin recruitment in CXCR4 receptor overexpressing cell line. Furthermore, UCUF-965 potentiates the CXCL12 maximal response in cAMP signaling pathway, activates CXCL12 stimulated migration in lymphoblast cells and modulates the levels of specific microRNA involved in the complex wound repair process, specifically in mouse fibroblasts. Our results indicate that UCUF-965 acts as a PAM agonist of the CXCR4 receptor. Furthermore, UCUF-965 enhanced angiogenesis markers and reduced wound healing time by 36% at 10.0 µM in diabetic mice models compared to untreated control.

Impaired biomechanical properties of diabetic skin implications in pathogenesis of diabetic wound complications.

Diabetic skin is known to have deficient wound healing properties, but little is known of its intrinsic biomechanical properties. We hypothesize that diabetic skin possesses inferior biomechanical properties at baseline, rendering it more prone to injury. Skin from diabetic and nondiabetic mice and humans underwent biomechanical testing. Real-time PCR was performed for genes integral to collagen synthesis and degradation. MMP-2 and MMP-9, and TIMP-1 protein levels were assessed by ELISA and zymography. Collagen I and III content was assessed using Western blot analysis. At baseline, both murine and human diabetic skin was biomechanically inferior compared to nondiabetic skin, with decreased maximum stress and decreased modulus (P < 0.001 and < 0.05, respectively). Surprisingly, the expression of genes involved in collagen synthesis were significantly up-regulated, and genes involved in collagen degradation were significantly down-regulated in murine diabetic skin (P < 0.01). In addition, MMP-2 and MMP-9/TIMP-1 protein ratios were significantly lower in murine diabetic skin (P < 0.05). Collagen I levels and I:III ratios were lower in diabetic skin (P < 0.05). These findings suggest that the predisposition of diabetics to wounds may be the result of impaired tissue integrity at baseline, and are due, in part, to a defect in the regulation of collagen protein synthesis at the post-transcriptional level.

Cardiomyocyte cyclooxygenase-2 influences cardiac rhythm and function.

Nonsteroidal anti-inflammatory drugs selective for inhibition of COX-2 increase heart failure and elevate blood pressure. The COX-2 gene was floxed and crossed into merCremer mice under the alpha-myosin heavy-chain promoter. Tamoxifen induced selective deletion of COX-2 in cardiomyocytes depressed cardiac output, and resulted in weight loss, diminished exercise tolerance, and enhanced susceptibility to induced arrhythmogenesis. The cardiac dysfunction subsequent to pressure overload recovered progressively in the knockouts coincident with increasing cardiomyocyte hypertrophy and interstitial and perivascular fibrosis. Inhibition of COX-2 in cardiomyocytes may contribute to heart failure in patients receiving nonsteroidal anti-inflammatory drugs specific for inhibition of COX-2.

An in vivo map of bone morphogenetic protein 2 post-transcriptional repression in the heart.

The Bmp2 3'untranslated region (UTR) sequence bears a sequence conserved between mammals and fishes that can post-transcriptionally activate or repress protein synthesis. We developed a map of embryonic cells in the mouse where this potent Bmp2 regulatory sequence functions by using a lacZ reporter transgene with a 3'UTR bearing two loxP sites flanking the ultra-conserved sequence. Cre-recombinase-mediated deletion of the ultra-conserved sequence caused strong ectopic expression in proepicardium, epicardium and epicardium-derived cells (EPDC) and in tissues with known epicardial contributions (coronary vessels and valves). Transient transfections of reporters in the epicardial/mesothelial cell (EMC) line confirmed this repression. Ectopic expression of the recombined transgene also occurred in the aorta, outlet septum, posterior cardiac plexus, cardiac and extracardiac nerves and neural ganglia. Bmp2 is dynamically regulated in the developing heart. 3'UTR-mediated mechanisms that restrain BMP2 synthesis may be relevant to congenital heart and vasculature malformations and to adult diseases involving aberrant BMP2 synthesis.