miR-122-5p targets GREM2 to protect against glucocorticoid-induced endothelial damage through the BMP signaling pathway

Protective effects of Gumibao recipe on glucocorticoid-included bone microcirculatory endothelial cell injury and the underlying mechanism

OBJECTIVE

To investigate the protective effects of Gumibao recipe on glucocorticoid-included bone microcirculatory endothelial cell (BMEC) injury, and elucidate the possible underlying mechanism.

METHODS

BMECs were treated with different concentrations of hydrocortisone at different time points, and the viability as well as migration of BMECs were evaluated; furthermore, the release of LDH, levels of VEGF, PAI-1, t-PA, and the content of NO by BMECs have been evaluated by commercially available kits; moreover, the expressions of eNOS, p-PI3K, p-Akt and p-mTOR in BMECs were examined by WB methods. Next, hydrocortisone treated BMECs were co-treated with Gumibao recipe, and the viability, migration and autophagy of BMECs were evaluated.

RESULTS

0.2 mg/ml and 0.3 mg/ml hydrocortisone significantly decreased viability and migration ability of BMECs, and also impeded the endothelial function of BMECs by decreasing the levels of VEGF, t-PA, the content of NO, and increasing the level of PAI-1. Gumibao medicated serum markedly increased the viability and migration of BMECs, and also increased the levels of VEGF, t-PA, the content of NO, meanwhile decreased the level of PAI-1 in 0.3 mg/ml hydrocortisone treated BMECs; moreover, glucocorticoids inhibited the autophagy of BMECs, and Gumibao recipe significantly increased the autophagy of BMECs; meanwhile, autophagy inhibitor 3-MA partially blocked the protective effects of Gumibao recipe. Finally, gumibao recipe partially abrogated the inhibitory effects of hydrocortisone on the activation of PI3K/Akt/mTOR singling, and these effects were further counteracted by PI3K and mTOR inhibitor NVP-BEZ235.

CONCLUSIONS

We reported for the first time the protective effects of Gumibao recipe on glucocorticoid-included BMECs injury, and the possible underlying mechanism may be regulating the autophagy of BMECs via PI3K/AKT/mTOR signaling pathway.

Glutamine synthetase accelerates re-endothelialization of vascular grafts by mitigating endothelial cell dysfunction in a rat model

Endothelial cell (EC) dysfunction within the aorta has long been recognized as a prominent contributor to the progression of atherosclerosis and the subsequent failure of vascular graft transplantation. However, the direct relationship between EC dysfunction and vascular remodeling remains to be investigated. In this study, we sought to address this knowledge gap by employing a strategy involving the release of glutamine synthetase (GS), which effectively activated endothelial metabolism and mitigates EC dysfunction. To achieve this, we developed GS-loaded small-diameter vascular grafts (GSVG) through the electrospinning technique, utilizing dual-component solutions consisting of photo-crosslinkable hyaluronic acid and polycaprolactone. Through an in vitro model of oxidized low-density lipoprotein-induced injury in human umbilical vein endothelial cells (HUVECs), we provided compelling evidence that the GSVG promoted the restoration of motility, angiogenic sprouting, and proliferation in dysfunctional HUVECs by enhancing cellular metabolism. Furthermore, the sequencing results indicated that these effects were mediated by miR-122-5p-related signaling pathways. Remarkably, the GSVG also exhibited regulatory capabilities in shifting vascular smooth muscle cells towards a contractile phenotype, mitigating inflammatory responses and thereby preventing vascular calcification. Finally, our data demonstrated that GS incorporation significantly enhanced re-endothelialization of vascular grafts in a ferric chloride-injured rat model. Collectively, our results offer insights into the promotion of re-endothelialization in vascular grafts by restoring dysfunctional ECs through the augmentation of cellular metabolism.

CHRDL2 activates the PI3K/AKT pathway to ameliorate glucocorticoid-induced damages to bone microvascular endothelial cells (BMECs)

Steroid-induced avascular necrosis of the femoral head (ANFH) is characterized by the death of bone tissues, leading to the impairment of normal reparative processes within micro-fractures in the femoral head. Glucocorticoid (GCs)-induced bone microvascular endothelial cell (BMEC) damage has been reported to contribute to ANFH development. In this study, differentially expressed genes (DEGs) between necrosis of the femoral head (NFH) and normal samples were analyzed based on two sets of online expression profiles, GSE74089 and GSE26316. Chordin-like 2 (CHRDL2) was found to be dramatically downregulated in NFH samples. In GCs-stimulated BMECs, cellular damages were observed alongside CHRDL2 down-regulation. GCs-caused cell viability suppression, cell apoptosis promotion, tubule formation suppression, and cell migration suppression were partially abolished by CHRDL2 overexpression but amplified by CHRDL2 knockdown; consistent trends were observed in GCs-caused alterations in the protein levels of VEGFA, VEGFR2, and BMP-9 levels, and the ratios of Bax/Bcl-2 and cleaved-caspase3/Caspase3. GC stimulation significantly inhibited PI3K and Akt phosphorylation in BMECs, whereas the inhibitor effects of GCs on PI3K and Akt phosphorylation were partially attenuated by CHRDL2 overexpression but further amplified by CHRDL2 knockdown. Moreover, CHRDL2 overexpression caused improvement in GCs-induced damages to BMECs that were partially eliminated by PI3K inhibitor LY294002. In conclusion, CHRDL2 is down-regulated in NFH samples and GCs-stimulated BMECs. CHRDL2 overexpression could improve GCs-caused BMEC apoptosis and dysfunctions, possibly via the PI3K/Akt pathway.

Research progress in the pathogenesis of hormone-induced femoral head necrosis based on microvessels: a systematic review

Hormonal necrosis of the femoral head is caused by long-term use of glucocorticoids and other causes of abnormal bone metabolism, lipid metabolism imbalance and blood microcirculation disorders in the femoral head, resulting in bone trabecular fracture, bone tissue necrosis collapse, and hip dysfunction. It is the most common type of non-traumatic necrosis of the femoral head, and its pathogenesis is complex, while impaired blood circulation is considered to be the key to its occurrence. There are a large number of microvessels in the femoral head, among which H-type vessels play a decisive role in the "angiogenesis and osteogenesis coupling", and thus have an important impact on the occurrence and development of femoral head necrosis. Glucocorticoids can cause blood flow injury of the femoral head mainly through coagulation dysfunction, endothelial dysfunction and impaired angiogenesis. Glucocorticoids may inhibit the formation of H-type vessels by reducing the expression of HIF-1α, PDGF-BB, VGEF and other factors, thus causing damage to the "angiogenesis-osteogenesis coupling" and reducing the ability of necrosis reconstruction and repair of the femoral head. Leads to the occurrence of hormonal femoral head necrosis. Therefore, this paper reviewed the progress in the study of the mechanism of hormone-induced femoral head necrosis based on microvascular blood flow at home and abroad, hoping to provide new ideas for the study of the mechanism of femoral head necrosis and provide references for clinical treatment of femoral head necrosis.

Differences in junction-associated gene expression changes in three rat models of diabetic retinopathy with similar neurovascular phenotype

Diabetic retinopathy, also defined as microvascular complication of diabetes mellitus, affects the entire neurovascular unit with specific aberrations in every compartment. Neurodegeneration, glial activation and vasoregression are observed consistently in models of diabetic retinopathy. However, the order and the severity of these aberrations varies in different models, which is also true in patients. In this study, we analysed rat models of diabetic retinopathy with similar phenotypes to identify key differences in the pathogenesis. For this, we focussed on intercellular junction-associated gene expression, which are important for the communication and homeostasis within the neurovascular unit. Streptozotocin-injected diabetic Wistar rats, methylglyoxal supplemented Wistar rats and polycystin-2 transgenic (PKD) rats were analysed for neuroretinal function, vasoregression and retinal expression of junction-associated proteins. In all three models, neuroretinal impairment and vasoregression were observed, but gene expression profiling of junction-associated proteins demonstrated nearly no overlap between the three models. However, the differently expressed genes were from the main classes of claudins, connexins and integrins in all models. Changes in Rcor1 expression in diabetic rats and Egr1 expression in PKD rats confirmed the differences in upstream transcription factor level between the models. In PKD rats, a possible role for miRNA regulation was observed, indicated by an upregulation of miR-26b-5p, miR-122-5p and miR-300-3p, which was not observed in the other models. In silico allocation of connexins revealed not only differences in regulated subtypes, but also in affected retinal cell types, as well as connexin specific upstream regulators Sox7 and miR-92a-3p. In this study, we demonstrate that, despite their similar phenotype, models for diabetic retinopathy exhibit significant differences in their pathogenic pathways and primarily affected cell types. These results underline the importance for more sensitive diagnostic tools to identify pathogenic clusters in patients as the next step towards a desperately needed personalized therapy.

Emerging roles of growth factors in osteonecrosis of the femoral head

Osteonecrosis of the femoral head (ONFH) is a potentially disabling orthopedic condition that requires total hip arthroplasty in most late-stage cases. However, mechanisms underlying the development of ONFH remain unknown, and the therapeutic strategies remain limited. Growth factors play a crucial role in different physiological processes, including cell proliferation, invasion, metabolism, apoptosis, and stem cell differentiation. Recent studies have reported that polymorphisms of growth factor-related genes are involved in the pathogenesis of ONFH. Tissue and genetic engineering are attractive strategies for treating early-stage ONFH. In this review, we summarized dysregulated growth factor-related genes and their role in the occurrence and development of ONFH. In addition, we discussed their potential clinical applications in tissue and genetic engineering for the treatment of ONFH.

Effects of 4-vinylcyclohexene diepoxide on the cell cycle, apoptosis, and steroid hormone secretion of goat ovarian granulosa cells

4-Vinylcyclohexene diepoxide (VCD) is a potentially hazardous industrial chemical that may enter a goat's body in various ways during industrial breeding. Ovarian granulosa cells (GCs) play a critical role in supporting follicle development and hormone synthesis. However, there are few studies on the effect of VCD on goat ovarian GCs. In this study, goat ovarian GCs were isolated and treated with VCD. The results showed that treatment with VCD increased the proportion of S phase and G2/M cells, but decreased the proportion of G1 phase. VCD treatment significantly inhibited the expression of cyclin A and cyclin-dependent kinase 2 (CDK2). But the expression levels of p21 and p27 were increased. VCD could induce an apparent increase in the proportion of apoptosis and the level of cleaved caspase 3. Treatment with VCD significantly reduced the progesterone and estrogen concentration in the medium in which goat ovarian GCs were cultured. Correspondingly, the expression level of steroidogenic acute regulatory protein (STAR) was significantly downregulated. Treatment with 0.25 and 0.5 mM VCD, the protein expression level of insulin-like growth factor 1 receptor (IGF1R) and Akt were significantly decreased. Moreover, treatment with 0.25 mM VCD significantly inhibited the phosphorylation of Akt. In conclusion, VCD exposure had cytotoxic effects such as decreased cell viability, disordered cell cycle, increased apoptosis, and interference with steroid hormone synthesis on goat GCs. These cytotoxic effects of VCD on goat GCs may be due to the downregulation of IGF1R and the inhibition of IGF1R/Akt signaling pathway.