SDF-1α Expression Research Articles

Repressing miR-23a promotes the transdifferentiation of pancreatic α cells to β cells via negatively regulating the expression of SDF-1α.

Pancreatic β-cell failure is a pathological feature in type 1 diabetes. One promising approach involves inducing transdifferentiation of related pancreatic cell types, specifically α cells that produce glucagon. The chemokine stromal cell-derived factor-1 alpha (SDF-1α) is implicated in pancreatic α-to-β like cell transition. Here, the serum level of SDF-1α was lower in T1D with C-peptide loss, the miR-23a was negatively correlated with SDF-1α. We discovered that exosomal miR-23a, secreted from β cells, functionally downregulates the expression of SDF-1α, leading to increased Pax4 expression and decreased Arx expression in vivo. Adenovirus-vectored miR-23a sponge and mimic were constructed to further explored the miR-23a on pancreatic α-to-β like cell transition in vitro, which yielded results consistent with our cell-based assays. Suppression of miR-23a upregulated insulin level and downregulated glucagon level in STZ-induced diabetes mice models, effectively promoting α-to-β like cell transition. Our findings highlight miR-23a as a new therapeutic target for regenerating pancreatic β cells from α cells.

LncRNA NEAT1/miR-146a-5p Axis Restores Normal Angiogenesis in Diabetic Foot Ulcers by Targeting mafG.

Non-healing lesions in diabetic foot ulcers are a significant effect of poor angiogenesis. Epigenetic regulators, mainly lncRNA and miRNA, are recognized for their important roles in disease progression. We deciphered the regulation of lncRNA NEAT1 through the miR-146a-5p/mafG axis in the progression of DFU. A lowered expression of lncRNA NEAT1 was associated with dysregulated angiogenesis through the reduced expression of mafG, SDF-1α, and VEGF in chronic ulcer subjects compared to acute DFU. This was validated by silencing NEAT1 by SiRNA in the endothelial cells which resulted in the transcriptional repression of target genes. Our in silico analysis identified miR-146a-5p as a potential target of lncRNA NEAT1. Further, silencing NEAT1 led to an increase in the levels of miR-146a-5p in chronic DFU subjects. This research presents the role of the lncRNA NEAT1/miR-146a-5p/mafG axis in enhancing angiogenesis in DFU.

VNS improves VSMC metabolism and arteriogenesis in infarcted hearts through m/n-AChR-Akt-SDF-1α in adult male rats

Vagal nerve stimulation (VNS) provides a novel therapeutic strategy for injured hearts by activating cholinergic anti-inflammatory pathways. However, little information is available on the metabolic pattern and arteriogenesis of VSMCs after MI. VNS has been shown to stimulate the expression of CPT1α, CPT1β, Glut1, Glut4 and SDF-1α in coronary VSMCs, decreasing the number of CD68-positive macrophages while increasing CD206-positive macrophages in the infarcted hearts, leading to a decrease in TNF-α and IL-1β accompanied by a reduced ratio of CD68- and CD206-positive cells, which were dramatically abolished by atropine and mecamylamine in vivo. Knockdown of SDF-1α substantially abrogated the effect of VNS on macrophagecell alteration and inflammatory factors in infarcted hearts. Mechanistically, ACh induced SDF-1α expression in VSMCs in a dose-dependent manner. Conversely, atropine, mecamylamine, and a PI3K/Akt inhibitor completely eliminated the effect of ACh on SDF-1α expression. Functionally, VNS promoted arteriogenesis and improved left ventricular performance, which could be abolished by Ad-shSDF-1α. Thus, VNS altered the VSMC metabolism pattern and arteriogenesis to repair the infarcted heart by inducing SDF-1α expression, which was associated with the m/nAChR-Akt signaling pathway.

Correlation between SDF-1α, CD34 positive hematopoietic stem cells and CXCR4 expression with liver fibrosis in CCl4 rat model

BackgroundOne of the most frequent disorders is liver fibrosis. An improved understanding of the different events during the process of liver fibrosis & its reversibility could be helpful in its staging and in finding potential therapeutic agents.AimThe goal of this research was to evaluate the relationship among CD34 + HPSCs, SDF-1α, and CXCR4 receptor expression with the percentage of the area of hepatic fibrosis.Materials and methodsThirty-six male Sprague-Dawley rats were separated into the control group, liver injury group & spontaneous reversion group. The liver injury was induced by using 2 ml/kg CCl4 twice a week. Flow cytometric examination of CD34 + cells in the blood & liver was performed. Bone marrow & liver samples were taken for evaluation of the SDF-1α mRNA by PCR. Liver specimens were stained for histopathological and CXCR4 immuno-expression evaluation.ResultsIn the liver injury group, the hepatic enzymes, fibrosis area percentage, CXCR4 receptor expression in the liver, CD34 + cells in the blood and bone marrow & the level SDF-1α in the liver and its concentration gradient were statistically significantly elevated with the progression of the liver fibrosis. On the contrary, SDF-1α in the bone marrow was statistically significantly reduced with the development of liver fibrosis. During the spontaneous reversion group, all the studied parameters apart from SDF-1α in the bone marrow were statistically substantially decreased compared with the liver injury group. We found a statistically substantial positive correlation between fibrosis area and all of the following: liver enzymes, CXCR4 receptor expression in the liver, CD34 + cells in the blood and liver, and SDF- 1α in the liver and its concentration gradient. In conclusion, in CCl4 rat model, the fibrosis area is significantly correlated with many parameters in the blood, bone marrow, and liver, which can be used during the process of follow-up during the therapeutic interventions.

The CXCR4-AT1 axis plays a vital role in glomerular injury via mediating the crosstalk between podocyte and mesangial cell

Glomeruli stand at the center of nephrons to accomplish filtration and albumin interception.Podocytes and mesangial cells are the major constituents in the glomeruli. However, their interdependency in glomerular injury has rarely been reported. Herein, we investigated the role of C-X-C chemokine receptor type 4 (CXCR4) in mediating the crosstalk between podocytes and mesangial cells. We found CXCR4 and angiotensin II (AngII) increased primarily in injured podocytes. However, type-1 receptor of angiotensin II (AT1) and stromal cell-derived factor 1α (SDF-1α), a ligand of CXCR4, were evidently upregulated in mesangial cells following the progression of podocyte injury. Ectopic expression of CXCR4 in 5/6 nephrectomy mice increased the decline of renal function and glomerular injury, accelerated podocyte injury and mesangial cell activation, and initiated CXCR4-AT1 axis signals. Additionally, treatment with losartan, an AT1 blocker, interrupted the cycle of podocyte injury and mesangial matrix deposition triggered by CXCR4. Podocyte-specific ablation of CXCR4 gene blocked podocyte injury and mesangial cell activation. In vitro, CXCR4 overexpression induced oxidative stress and renin angiotensin system (RAS) activation in podocytes, and triggered the communication between podocytes and mesangial cells. In cultured mesangial cells, AngII treatment induced the expression of SDF-1α, which was secreted into the supernatant to further promote oxidative stress and cell injury in podocytes. Collectively, these results demonstrate that the CXCR4-AT1 axis plays a vital role in glomerular injury via mediating pathologic crosstalk between podocytes and mesangial cells. Our findings uncover a novel pathogenic mechanism by which the CXCR4-AT1 axis promotes glomerular injury.

Vagus nerve stimulation-induced stromal cell-derived factor-l alpha participates in angiogenesis and repair of infarcted hearts.

We aim to explore the role and mechanism of vagus nerve stimulation (VNS) in coronary endothelial cells and angiogenesis in infarcted hearts. Seven days after rat myocardial infarction (MI) was prepared by ligation of the left anterior descending coronary artery, the left cervical vagus nerve was treated with electrical stimulation 1h after intraperitoneal administration of the α7-nicotinic acetylcholine inhibitor mecamylamine or the mAChR inhibitor atropine or 3days after local injection of Ad-shSDF-1α into the infarcted heart. Cardiac tissue acetylcholine (ACh) and serum ACh, tumour necrosis factor α (TNF-α), interleukin 1β (IL-1β) and interleukin 6 (IL-6) levels were detected by ELISA to determine whether VNS was successful. An inflammatory injury model in human coronary artery endothelial cells (HCAECs) was established by lipopolysaccharide and identified by evaluating TNF-α, IL-1β and IL-6 levels and tube formation. Immunohistochemistry staining was performed to evaluate CD31-positive vessel density and stromal cell-derived factor-l alpha (SDF-1α) expression in the MI heart in vivo and the expression and distribution of SDF-1α, C-X-C motif chemokine receptor 4 and CXCR7 in HCAECs in vitro. Western blotting was used to detect the levels of SDF-1α, V-akt murine thymoma viral oncogene homolog (AKT), phosphorylated AKT (pAKT), specificity protein 1 (Sp1) and phosphorylation of Sp1 in HCAECs. Left ventricular performance, including left ventricular systolic pressure, left ventricular end-diastolic pressure and rate of the rise and fall of ventricular pressure, should be evaluated 28days after VNS treatment. VNS was successfully established for MI therapy with decreases in serum TNF-α, IL-1β and IL-6 levels and increases in cardiac tissue and serum ACh levels, leading to increased SDF-1α expression in coronary endothelial cells of MI hearts, triggering angiogenesis of MI hearts with increased CD31-positive vessel density, which was abolished by the m/nAChR inhibitors mecamylamine and atropine or knockdown of SDF-1α by shRNA. ACh promoted SDF-1α expression and its distribution along with the branch of the formed tube in HCAECs, resulting in an increase in the number of tubes formed in HCAECs. ACh increased the levels of pAKT and phosphorylation of Sp1 in HCAECs, resulting in inducing SDF-1α expression, and the specific effects could be abolished by mecamylamine, atropine, the PI3K/AKT blocker wortmannin or the Sp1 blocker mithramycin. Functionally, VNS improved left ventricular performance, which could be abolished by Ad-shSDF-1α. VNS promoted angiogenesis to repair the infarcted heart by inducing SDF-1α expression and redistribution along new branches during angiogenesis, which was associated with the m/nAChR-AKT-Sp1 signalling pathway.

SDF-1α promotes subchondral bone sclerosis and aggravates osteoarthritis by regulating the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells

BackgroundSubchondral bone sclerosis is a major feature of osteoarthritis (OA), and bone marrow mesenchymal stem cells (BMSCs) are presumed to play an important role in subchondral bone sclerosis. Accumulating evidence has shown that stromal cell-derived factor-1α (SDF-1α) plays a key role in bone metabolism-related diseases, but its role in OA pathogenesis remains largely unknown. The purpose of this study was to explore the role of SDF-1α expressed on BMSCs in subchondral bone sclerosis in an OA model.MethodsIn the present study, C57BL/6J mice were divided into the following three groups: the sham control, destabilization of the medial meniscus (DMM), and AMD3100-treated DMM (DMM + AMD3100) groups. The mice were sacrificed after 2 or 8 weeks, and samples were collected for histological and immunohistochemical analyses. OA severity was assessed by performing hematoxylin and eosin (HE) and safranin O-fast green staining. SDF-1α expression in the OA model was measured using an enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (q-PCR), and immunohistochemistry. Micro-CT was used to observe changes in subchondral bone in the OA model. CD44, CD90, RUNX2, and OCN expression in subchondral bone were measured using q-PCR and immunohistochemistry. In vitro, BMSCs were transfected with a recombinant lentivirus expressing SDF-1α, an empty vector (EV), or siRNA-SDF-1α. Western blot analysis, q-PCR, and immunofluorescence staining were used to confirm the successful transfection of BMSCs. The effect of SDF-1α on BMSC proliferation was evaluated by performing a CCK-8 assay and cell cycle analysis. The effect of SDF-1α on the osteogenic differentiation of BMSCs was assessed by performing alkaline phosphatase (ALP) and alizarin red S (ARS) staining. Cyclin D1, RUNX2 and OCN expression were measured using Western blot analysis, q-PCR, and immunofluorescence staining.ResultsSDF-1α expression in the DMM-induced OA model increased. In the DMM + AMD3100 group, subchondral bone sclerosis was alleviated, OA was effectively relieved, and CD44, CD90, RUNX2, and OCN expression in subchondral bone was decreased. In vitro, high levels of SDF-1α promoted BMSC proliferation and increased osteogenic differentiation. Cyclin D1, RUNX2, and OCN expression increased.ConclusionThe results of this study reveal a new molecular mechanism underlying the pathogenesis of OA. The targeted regulation of SDF-1α may be clinically effective in suppressing OA progression.

Inhibition of SRC-mediated integrin signaling in bone marrow niche enhances hematopoietic stem cell function

SummaryInteraction with microenvironmental factors is crucial for the regulation of hematopoietic stem cell (HSC) function. Stroma derived factor (SDF)-1α supports HSCs in the quiescent state and is central to the homing of transplanted HSCs. Here, we show that integrin signaling regulates Sdf-1α expression transcriptionally. Systemic deletion of Periostin, an Integrin-αv ligand, showed increased expression of Sdf-1α in bone marrow (BM) niche. Pharmacological inhibition or CRISPR-Cas9-mediated deletion of SRC, resulted in a similar increase in the chemokine expression in vitro. Importantly, systemic SRC-inhibition led to increase in SDF-1α levels in BM plasma. This resulted in a robust increase (14.05 ± 1.22% to 29.11 ± 0.69%) in the homing efficiency of transplanted HSCs. In addition, we observed enhancement in the recovery of blood cell counts following radiation injury, indicating an enhanced hematopoietic function. These results establish a role of SRC-mediated integrin signaling in the transcriptional regulation of Sdf-1α. This mechanism could be harnessed further to improve the hematopoietic function.

Curcumol Undermines SDF-1α/CXCR4/NF-κB Signaling Pathway to Suppress the Progression of Chronic Atrophic Gastritis (CAG) and Gastric Cancer.

CAG is the most common precancerous disease of gastric cancer, which belongs to a kind of chronic gastritis. CAG is in close association with gastric cancer, which makes itself a critical node clinically in cancer prevention and treatment. Curcumol is a main active monomer in Fuzheng Huowei decoction, which has the properties of antioxidant, antiviral, and antitumor. In this study, the expression of SDF-1α/CXCR4/NF-κB was detected by in vivo and in vitro methods. Then, we found that the expressions of NF-κB, SDF-1α, CXCR4, and p-NF-κB were decreased in the curcumol treatment group. Curcumol inhibited gastric cancer cells' viability, migration, and invasion and induced their apoptosis. After adding the lentivirus overexpressing SDF-1α to the curcumol treatment group, it was found that SDF-1α, CXCR4, NF-κB, and p-NF-κB protein expressions were all increased, and the effect of curcumol on gastric cancer cells was reversed. In the nude mouse experiment, the tumor volume in the curcumol + SDF-1α group was the largest, and the tumor volume in the Fuzheng Huowei decoction + NC group was the smallest. In conclusion, curcumol effectively protects gastric tissue and inhibits the viability of gastric cancer cells, and curcumol regulates SDF-1α/CXCR4/NF-κB to play a therapeutic role in chronic atrophic gastritis and gastric cancer.

Therapeutic Effect of Curcumol on Chronic Atrophic Gastritis (CAG) and Gastric Cancer Is Achieved by Downregulating SDF-1α/CXCR4/VEGF Expression.

CAG is an essential procession of the transformation from gastritis into gastric cancer. A series of timely moves of diagnosis, treatment, and monitoring towards CAG to anticipate the potential population at risk of gastric cancer is an effective means to prevent gastric cancer occurrence. The main active monomer in Fuzheng Huowei Decoction is Curcumol, which is an indispensable ingredient in the treatment to CAG and gastric cancer. In this study, the CAG model, in vitro cultured gastric cancer cells, and participating nude mice were treated with Curcumol, and alterations in SDF-1α/CXCR4/VEGF expression were estimated using the assays of immunohistochemistry and Western blot. MTT, flow cytometry, transwell, HE staining, and tumor volume determination were applied for the verification of the regulatory effects of Curcumol on CAG and gastric cancer cells. The results showed that the expressions of VEGF, SDF-1α, CXCR4, and CD34 decreased in our CAG model with Curcumol treatment. Curcumol is in procession of an inhibitory effect toward the activity, migration, and invasion of gastric cancer cells, and it would also result in gastric cancer cells' apoptosis. We subsequently added SDF-1α overexpressing lentivirus to the Curcumol-treated group and found that the expressions of SDF-1α, CXCR4, and VEGF protein increased, and the inhibitory effect of Curcumol on gastric cancer cells was withdrawn. Our nude mouse experiment showed that Curcumol + SDF-1α group ended up with the largest tumor volume, while Fuzheng Huowei + NC group was with the smallest tumor volume. In conclusion, Curcumol is able to effectively protect the gastric tissue and suppress gastric cancer cells' viability. Curcumol functions as a therapeutic factor in chronic atrophic gastritis and gastric cancer by downregulating SDF-1α/CXCR4/VEGF expression.

Abstract P1027: Cardioprotective Effects Of Genetically Engineered Cardiac Stem Cells By Spheroid Formation On Ischemic Cardiomyocytes

Background: Sca-1+ cardiac stem cells and their limited proliferative potential were major limiting factors for use in various studies. Methods: Therefore, the effects of sphere genetically engineered cardiac stem cells (S-GECS) inserted with telomerase reverse transcriptase (TERT) were investigated to examine cardiomyocyte survival under hypoxic conditions. GECS was obtained from hTERT-immortalized Sca-1+ cardiac stem cell (CSC) lines, and S-GECS were generated using poly-HEMA. Results: The optimal conditions for S-GECS was determined to be 1,052 GECS cells/mm 2 and a 48 hours culture period. Compared to adherent-GECS (A-GECS) and S-GECS showed significantly higher mRNA expression of the growth factors SDF-1α and CXCR4. S-GECS conditioned medium (CM) significantly reduced the proportion of early and late apoptotic cardiomyoblasts during CoCl 2 -induced hypoxic injury; however, gene silencing via CXCR4 siRNA deteriorated the protective effects of S-GECS against hypoxic injury. As downstream pathways of SDF-1α/CXCR4, the Erk and Akt signaling pathways were stimulated in the presence of S-GECS CM. S-GECS transplantation into a rat acute myocardial infarction model improved cardiac function and reduced the fibrotic area. These cardioprotective effects were confirmed to be related with the SDF-1α/CXCR4 pathway. Conclusions: Our findings suggest that paracrine factors secreted from transplanted cells may protect host cardiomyoblasts in the infarcted myocardium, contributing to beneficial left ventricle (LV) remodeling after acute myocardial infarction (AMI).

Inflammation down regulates stromal cell-derived factor 1α in the early phase of pulpitis

The key to prevent pulp necrosis in the early stage of pulpitis is to promote tissue repair, which begins with cell migration. Stromal cell-derived factor 1α (SDF-1α) has been proven to promote cell migration. Related research has so far concentrated on the biological effects of SDF-1α while its expression in pulpitis is still unclear. We investigated the effect of inflammation on SDF-1α in dental pulp and the underlying regulatory mechanisms. First, rat pulpitis models were established by exposing pulp. SDF-1α was decreased on the 3rd day but increased on the 7th day. Next, lipopolysaccharide from Porphyromonas gingivalis (Pg.LPS) was applied to dental pulp cells (DPCs). Within 24 h, SDF-1α decreased, but after 48 h, it steadily increased. Similarly, SDF-1α expression in human chronic pulpitis tissues was also increased. To investigate the effect of altered SDF-1α on DPC migration, cell supernatants collected following Pg.LPS treatment were utilized to stimulate DPCs, and the number of migrated cells was correlated with changes in SDF-1α secretion. Finally, we explored the regulatory mechanisms of SDF-1α down-regulation in the early phase of pulpitis. Within 24 h, JNK/c-Jun pathway was activated in DPC inflammation. When JNK pathway was suppressed, SDF-1α rose. Furthermore, tumor necrosis factor receptor 2 (TNFR2) and apoptosis signal-regulated kinase-interacting protein 1 (AIP1) were up-regulated. Knockdown of them abolished Pg.LPS-induced activation of JNK and c-Jun(Ser63) and significantly enhanced SDF-1α. Our findings indicated that in the early phase of pulpitis, inflammation suppressed SDF-1α by up-regulating TNFR2 and AIP1, which activated JNK/c-Jun(Ser63) pathway.

Intravenous Injection of SDF-1α-overexpressing Bone Marrow Mesenchymal Stem Cells has a Potential Protective Effect on Myocardial Ischemia in Mice.

Neutrophils are involved in the injury of myocytes during myocardial ischemia (MI). Stem cells migrate to the site of myocardial injury under homing signals and play a protective role, such as inhibiting inflammation. Chemokine SDF-1α and its related receptor CXCR4 are upregulated after myocardial infarction, which may play an important role in stem cell homing. This study aimed to explore the potential therapeutic effect of SDF-1α-modified bone marrow mesenchymal stem cells on myocardial ischemia/reperfusion (I/R) injury. We explored the role of SDF-1α modified bone marrow mesenchymal stem cells in vivo and in vitro. SDF-1α and CXCR4 expression was detected under hypoxia/reoxygenation (H/R) condition. Cell migration was detected by the transwell method. The levels of SDF-1α and IL-1β, IL-6, IL-10, and TNF-α were detected in different groups. In vitro, SDF-1α was mainly upregulated and secreted by cardiomyocytes, and cardiomyocytes recruited stem cells through the SDF-1/CXCR4 pathway to reduce the damage of polymorphic mononuclear neutrophils to cardiomyocytes under H/R. Upregulation of SDF-1α increased the migration ability of BMSC Stem Cells to H/R-induced cardiomyocytes. In vivo, intravenous injection of SDF-1α genemodified BMSC Stem Cells reduced inflammatory infiltration in the injured area as well as the level of systemic inflammatory factors. SDF-1α-overexpressing BMSC Stem Cells protected the heart function of mice and significantly reduced I/R-induced myocardial injury, which has a potential protective effect on MI.

Albumin-Based Nanoparticles Loaded with miR-503 Antagonist Facilitate Neovascularization in the Ischemic Area of Myocardial Infarction

Albumin is successfully applied as a nanocarrier in the clinical nanomedicine and the abnormal miR-503 expression is related to the development of myocardial infarction (MI). This study aimed to explore the efficacy of albumin nanoparticles (NPs)-based delivery of miR-503 antagonist for MI therapy. After establishment of an animal model of MI, mice were administered albumin NPs loaded with miR-503 agonist or antagonist, normal saline (model group), CCNE1 agonist, or CCNE1 inhibitor (n = 10) with 10 mice sham-operated. Murine peripheral blood was collected to measure endothelial progenitor cells (EPCs) in peripheral blood along with analysis of miR-503, CCNE1 and SDF-1α expression by RT-qPCR, formation of new blood vessels and EPCs viability. Albumin NPs loaded with miR-503 antagonist increased EPCs number and new blood vessels formation, accompanied with down-regulation of miR-503 and up-regulation of SDF-1α and CCNE1. The NPs carrying miR-503 agonist exerted an opposite activity with less EPCs and new blood vessels than sham-operated group without significant difference between agonist group and model group. Besides, miR-503 antagonist promoted EPCs viability. Furthermore, inhibition of CCNE1 suppressed blood vessel formation and miR-503 targeted CCNE1. In conclusion, albumin-based NPs loaded with miR-503 antagonist decrease miR-503 expression and increase CCNE1 and SDF-1α expression to promotes EPCs viability and enhance the formation of new blood vessels, thereby improving MI.

IDF21-0448 Role of miR27b on the regulation of angiogenesis in diabetic foot ulcer through Nrf2 signaling

Background: Diabetic foot ulcer (DFU) is a serious microvascular complication in diabetic patients with significant morbidity and mortality. The prevalence of chronic wounds continues to be a key focus of wound care research. Prolonged hyperglycemia-induced slow lymphangiogenesis associated with chronic oxidative stress is a major hallmark for poor wound closure in diabetic patients. Nrf2, a stress-activated transcription factor, combat oxidative stress by increasing antioxidant defense in many diseases, including diabetes. Recently we have reported the association of Nrf2 on the regulation of angiogenesis in DFU patients. Aim: This study aims to decipher the role of miR27b on the regulation of angiogenesis in DFU through Nrf2 signaling and further validation using in vitro system. Method: This study recruited a total of 20 patients with acute DFU and chronic DFU with no other diabetic complications. The expression of miR27b, Nrf2, HO1, SDF-1a and VEGF were studied in the tissues biopsies of study subjects using qPCR. The in vitro studies were carried out using human endothelial cells, EA.hy926 (ECs), exposed to a hyperglycemic microenvironment (High glucose with cytokine cocktail) for 24 hrs. The role of miR27b in regulating angiogenesis was demonstrated using antisense oligonucleotide targeting miR27b. Further, the association of Nrf2 with miR27b was studied using small molecule Nrf2 activators under the hyperglycemic microenvironment. Results: The wound size, levels of CRP, and WBC counts were significantly higher in chronic than in acute DFU. We found a significant reduction in Nrf2, HO1, SDF-1α, and VEGF gene expressions and miR27b in chronic DFU subjects compared with acute DFU subjects. Further, the ECs under hyperglycemic microenvironment also showed reduced expressions of miR27b, Nrf2, HO1 and other angiogenic markers. The knockdown of miR27b using antisense revealed the positive regulation of miR27b in angiogenesis. Further, we observed a significant up-regulation of miR27b in ECs exposed to small molecule Nrf2 activators such as pterostilbene and resveratrol under a hyperglycemic microenvironment. Discussion: Angiogenesis is the crucial step in the wound healing process which is impaired in DFU. Our results were consistent with a few earlier reports suggesting a reduced level of angiogenic markers such as SDF-1α and VEGF with the progression of DFU. We also found a decreased expression of the master regulator Nrf2 in the progression of DFU. Further, we have studied miR27b mediated Nrf2 regulation in tissue biopsies of chronic DFU patients and confirmed by in vitro studies. Inhibiting miR27b by antisense in ECs decreased angiogenic signaling, suggesting its positive role in wound healing. Of note, we confirmed the association of miR27b with the Nrf2 loop by exposing ECs with Nrf2 activators and ameliorated the dysregulated angiogenic signaling. In conclusion, our findings from this study have shown miR27b as an upstream target of Nrf2 that regulates angiogenesis in DFU through Nrf2.

LncRNA TINCR improves cardiac hypertrophy by regulating the miR-211-3p-VEGFB-SDF-1α-CXCR4 pathway

AbstractCardiac hypertrophy is a common cardiovascular disease that is found worldwide and is characterized by heart enlargement, eventually resulting in heart failure. Exploring the regulatory mechanism of cardiac hypertrophy is beneficial for understanding its pathogenesis and treatment. In our study, we have showed TINCR was downregulated and miR-211–3p was upregulated in TAC- or Ang II-induced models of cardiac hypertrophy. Dual luciferase and RIP assays revealed that TINCR served as a competitive endogenous RNA (ceRNA) for miR-211–3p. Then, we observed that knockdown of miR-211–3p alleviated TAC- or Ang II-induced cardiac hypertrophy both in vivo and in vitro. Mechanistically, we demonstrated that miR-211–3p directly targeted VEGFB and thus regulated the expression of SDF-1α and CXCR4. Rescue assays further confirmed that TINCR suppressed the progression of cardiac hypertrophy by competitively binding to miR-211–3p, thereby enhancing the expression of VEGFB and activating the VEGFB-SDF-1α- CXCR4 signal. Furthermore, overexpression of TINCR suppressed TAC-induced cardiac hypertrophy in vivo by targeting miR-211–3p-VEGFB-SDF-1α- CXCR4 signalling. In conclusion, our research suggests that LncRNA TINCR improves cardiac hypertrophy by targeting miR-211–3p, thus relieving its suppressive effects on the VEGFB-SDF-1α-CXCR4 signalling axis. TINCR and miR-211–3p might act as therapeutic targets for the treatment of cardiac hypertrophy.Cardiac hypertrophy is a common cardiovascular disease worldwide, and this study may provide novel potential therapeutic targets. The authors demonstrate that TINCR improves cardiac hypertrophy by acting as a competitive endogenous RNA for miR-211-3p and thus relieving its suppressive effects on the VEGFB-SDF-1α-CXCR4 signalling axis.

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 β-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.

Melittin Prevents Metastasis of Epidermal Growth Factor-Induced MDA-MB-231 Cells through The Inhibition of The SDF-1α/CXCR4 Signaling Pathway.

Objective Melittin is one of the natural components of bee venom (Apis mellifera), and its anticancer and antimetastatic properties have been well established, but the underlying mechanism remains elusive. The MDA-MB-231 is a triple- negative cell line that is highly aggressive and invasive. Besides, many critical proteins are involved in tumor invasion and metastasis. In this study, we investigated whether melittin inhibits the migration and metastasis of epidermal growth factor (EGF)-induced MDA-MB-231 cells via the suppression of SDF-1α/CXCR4 and Rac1-mediated signaling pathways. Materials and Methods In this experimental study, cells were treated with melittin (0.5-4 μg/ml), and the toxicity of melittin was assessed by the MTT assay. Afterward, the migration assay was conducted to measure the degree of the migration of EGF-induced cells. The western blot technique was performed to analyze the rate of Rac1, p-Rac1, SDF- 1α, and CXCR4 expression in different groups. Results The results demonstrated that melittin markedly suppressed the migration of EGF-induced cells and decreased the expression of p-Rac1, CXCR4, and SDF-1α proteins. ConclusionThe results of the present study suggested that the anti-tumor properties of melittin could be through the blocking of the SDF-1α/CXCR4 signaling pathway, which is beneficial for the reduction of tumor migration and invasion.

An ApoA-I Mimic Peptide of 4F Promotes SDF-1α Expression in Endothelial Cells Through PI3K/Akt/ERK/HIF-1α Signaling Pathway.

Atherosclerosis (AS) seriously impairs the health of human beings and is manifested initially as endothelial cells (ECs) impairment and dysfunction in vascular intima, which can be alleviated through mobilization of endothelial progenitor cells (EPCs) induced by stromal-cell-derived factor-1α (SDF-1α). A strong inverse correlation between HDL and AS has been proposed. The aim of the present work is to investigate whether 4F, an apolipoprotein A-I (apoA-I, major component protein of HDL) mimic peptide, can upregulate SDF-1α in mice and human umbilical vein endothelial cells (HUVECs) and the underlying mechanism. The protein levels of SDF-1α were measured by ELISA assay. Protein levels of HIF-1α, phosphorylated Akt (p-Akt), and phosphorylated ERK (p-ERK) were evaluated by Western blotting analysis. The results show that L-4F significantly upregulates protein levels of HIF-1α, Akt, and ERK, which can be inhibited by the PI3K inhibitor, LY294002, or ERK inhibitor, PD98059, respectively. Particularly, LY294002 can downregulate the levels of p-ERK, while PD98059 cannot suppress that of p-Akt. D-4F can upregulate the levels of HIF, p-Akt, and p-ERK in the abdominal aorta and inferior vena cava from mice. These results suggest that 4F promotes SDF-1α expression in ECs through PI3K/Akt/ERK/HIF-1α signaling pathway.

11,12 Epoxyeicosatrienoic Acid Rescues Deteriorated Wound Healing in Diabetes

Epoxyeicosatrienoic acids (EET) facilitate regeneration in different tissues, and their benefit in dermal wound healing has been proven under normal conditions. In this study, we investigated the effect of 11,12 EET on dermal wound healing in diabetes. We induced diabetes by i.p. injection of streptozotocin 2 weeks prior to wound creation on the dorsal side of the mouse ear. 11,12 EET was applied every second day on the wound, whereas the control groups received only solvent. Epithelialization was monitored every second day intravitally up to wound closure. Wounds were stained for VEGF, CD31, TGF-β, TNF-α, SDF-1α, NF-κB, and Ki-67, and fibroblasts were counted after hematoxylin-eosin stain on days 3, 6, 9, and 16 after wounding. After induction of diabetes, wounds closed on day 13.00 ± 2.20 standard deviation (SD). Local 11,12 ETT application improved wound closure significantly to day 8.40 ± 1.39 SD. EET treatment enhanced VEGF and CD31 expression in wounds on day 3. It also seemed to raise TNF-α level on all days investigated as well as TGF-β level on days 3 and 6. A decrease in NF-κB could be observed on days 9 and 16 after EET application. The latter findings were not significant. SDF-1α expression was not influenced by EET application, and Ki-67 was significantly less in the EET group on day 9 after EET application. The number of fibroblasts was significantly increased on day 9 after the 11,12 EET application. 11,12 EET improve deteriorated wound healing in diabetes by enhancing neoangiogenesis, especially in the early phase of wound healing. Furthermore, they contribute to the dissolution of the initial inflammatory reaction, allowing the crucial transition from the inflammatory to proliferative phase in wound healing.