Hyperglycemia-induced Bcl-2/Bax-mediated apoptosis of Schwann cells via mTORC1/S6K1 inhibition in diabetic peripheral neuropathy

Systematic investigation of Radix Salviae for treating diabetic peripheral neuropathy disease based on network Pharmacology

BACKGROUND

Diabetic peripheral neuropathy (DPN) is a debilitating complication of diabetes mellitus with limited available treatment options. Radix Salviae, a traditional Chinese herb, has shown promise in treating DPN, but its therapeutic mech-anisms have not been systematically investigated.

AIM

Radix Salviae (Danshen in pinin), a traditional Chinese medicine (TCM), is widely used to treat DPN in China. However, the mechanism through which Radix Salviae treats DPN remains unclear. Therefore, we aimed to explore the mechanism of action of Radix Salviae against DPN using network pharmacology.

METHODS

The active ingredients and target genes of Radix Salviae were screened using the TCM pharmacology database and analysis platform. The genes associated with DPN were obtained from the Gene Cards and OMIM databases, a drug-com-position-target-disease network was constructed, and a protein-protein inter-action network was subsequently constructed to screen the main targets. Gene Ontology (GO) functional annotation and pathway enrichment analysis were performed via the Kyoto Encyclopedia of Genes and Genomes (KEGG) using Bioconductor.

RESULTS

A total of 56 effective components, 108 targets and 4581 DPN-related target genes of Radix Salviae were screened. Intervention with Radix Salviae for DPN mainly involved 81 target genes. The top 30 major targets were selected for enrichment analysis of GO and KEGG pathways.

CONCLUSION

These results suggested that Radix Salviae could treat DPN by regulating the AGE-RAGE signaling pathway and the PI3K-Akt signaling pathway. Therefore, Danshen may affect DPN by regulating inflammation and apoptosis.

The role of kinases in peripheral nerve regeneration: mechanisms and implications

Peripheral nerve injury disease is a prevalent traumatic condition in current medical practice. Despite the present treatment approaches, encompassing surgical sutures, autologous nerve or allograft nerve transplantation, tissue engineering techniques, and others, an effective clinical treatment method still needs to be discovered. Exploring novel treatment methods to improve peripheral nerve regeneration requires more effort in investigating the cellular and molecular mechanisms involved. Many factors are associated with the regeneration of injured peripheral nerves, including the cross-sectional area of the injured nerve, the length of the nerve gap defect, and various cellular and molecular factors such as Schwann cells, inflammation factors, kinases, and growth factors. As crucial mediators of cellular communication, kinases exert regulatory control over numerous signaling cascades, thereby participating in various vital biological processes, including peripheral nerve regeneration after nerve injury. In this review, we examined diverse kinase classifications, distinct nerve injury types, and the intricate mechanisms involved in peripheral nerve regeneration. Then we stressed the significance of kinases in regulating autophagy, inflammatory response, apoptosis, cell cycle, oxidative processes, and other aspects in establishing conductive microenvironments for nerve tissue regeneration. Finally, we briefly discussed the functional roles of kinases in different types of cells involved in peripheral nerve regeneration.

Diabetic peripheral neuropathy: pathogenetic mechanisms and treatment

Diabetic peripheral neuropathy (DPN) refers to the development of peripheral nerve dysfunction in patients with diabetes when other causes are excluded. Diabetic distal symmetric polyneuropathy (DSPN) is the most representative form of DPN. As one of the most common complications of diabetes, its prevalence increases with the duration of diabetes. 10-15% of newly diagnosed T2DM patients have DSPN, and the prevalence can exceed 50% in patients with diabetes for more than 10 years. Bilateral limb pain, numbness, and paresthesia are the most common clinical manifestations in patients with DPN, and in severe cases, foot ulcers can occur, even leading to amputation. The etiology and pathogenesis of diabetic neuropathy are not yet completely clarified, but hyperglycemia, disorders of lipid metabolism, and abnormalities in insulin signaling pathways are currently considered to be the initiating factors for a range of pathophysiological changes in DPN. In the presence of abnormal metabolic factors, the normal structure and function of the entire peripheral nervous system are disrupted, including myelinated and unmyelinated nerve axons, perikaryon, neurovascular, and glial cells. In addition, abnormalities in the insulin signaling pathway will inhibit neural axon repair and promote apoptosis of damaged cells. Here, we will discuss recent advances in the study of DPN mechanisms, including oxidative stress pathways, mechanisms of microvascular damage, mechanisms of damage to insulin receptor signaling pathways, and other potential mechanisms associated with neuroinflammation, mitochondrial dysfunction, and cellular oxidative damage. Identifying the contributions from each pathway to neuropathy and the associations between them may help us to further explore more targeted screening and treatment interventions.

Rubia cordifolia L. Attenuates Diabetic Neuropathy by Inhibiting Apoptosis and Oxidative Stress in Rats

BACKGROUND

Diabetic neuropathy is a debilitating manifestation of long-term diabetes mellitus. The present study explored the effects of the roots of Rubia cordifolia L. (R. cordifolia L.) in the Wistar rat model for diabetic neuropathy and possible neuroprotective, antidiabetic, and analgesic mechanisms underlying this effect.

MATERIALS AND METHODS

Rats were divided into five experimental groups. An amount of 0.25% carboxy methyl cellulose (CMC) in saline and streptozotocin (STZ) (60 mg/kg) was given to group 1 and group 2, respectively. Group 3 was treated with STZ and glibenclamide simultaneously while groups 4 and 5 were simultaneously treated with STZ and hydroalcoholic extract of the root of R. cordifolia, respectively. Hot plate and cold allodynias were used to evaluate the pain threshold. The antioxidant effects of R. cordifolia were assessed by measuring Thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD). At the end of the study, sciatic nerve and brain tissues were collected for histopathological study. Bcl-2 proteins, cleaved caspase-3, and Bax were assessed through the Western blot method.

RESULTS

R. cordifolia significantly attenuated paw withdrawal and tail flick latency in diabetic neuropathic rats. R. cordifolia significantly (p < 0.01) improved the levels of oxidative stress. It was found to decrease blood glucose levels and to increase animal weight in R. cordifolia-treated groups. Treatment with R. cordifolia suppressed the cleaved caspase-3 and reduced the Bax:Bcl2 ratio in sciatic nerve and brain tissue compared to the diabetic group. Histopathological analysis also revealed a marked improvement in architecture and loss of axons in brain and sciatic nerve tissues at a higher dose of R. cordifolia (400 mg/kg).

CONCLUSION

R. cordifolia attenuated diabetic neuropathy through its antidiabetic and analgesic properties by ameliorating apoptosis and oxidative stress.

From Innate Immunity to Metabolic Disorder: A Review of the NLRP3 Inflammasome in Diabetes Mellitus

The role of the NLRP3 inflammasome is pivotal in the pathophysiology and progression of diabetes mellitus (DM), encompassing both type 1 (T1D), or type 2 (T2D). As part of the innate immune system, NLRP3 is also responsible for the chronic inflammation triggered by hyperglycemia. In both conditions, NLRP3 facilitates the release of interleukin-1β and interleukin-18. For T1D, NLRP3 perpetuates the autoimmune cascade, leading to the destruction of pancreatic islet cells. In T2D, its activation is associated with the presence of insulin resistance. NLRP3 activation is also instrumental for the presence of numerous complications associated with DM, microvascular and macrovascular. A considerable number of anti-diabetic drugs have demonstrated the ability to inhibit the NLRP3 inflammasome.

Emerging Nonpharmacologic Interventions to Treat Diabetic Peripheral Neuropathy

Significance: Diabetic peripheral neuropathy (DPN), a complication of metabolic syndrome, type I and type II diabetes, leads to sensory changes that include slow nerve conduction, nerve degeneration, loss of sensation, pain, and gate disturbances. These complications remain largely untreatable, although tight glycemic control can prevent neuropathy progression. Nonpharmacologic approaches remain the most impactful to date, but additional advances in treatment approaches are needed. Recent Advances: This review highlights several emerging interventions, including a focus on dietary interventions and physical activity, that continue to show promise for treating DPN. We provide an overview of our current understanding of how exercise can improve aspects of DPN. We also highlight new studies in which a ketogenic diet has been used as an intervention to prevent and reverse DPN. Critical Issues: Both exercise and consuming a ketogenic diet induce systemic and cellular changes that collectively improve complications associated with DPN. Both interventions may involve similar signaling pathways and benefits but also impact DPN through unique mechanisms. Future Directions: These lifestyle interventions are critically important as personalized medicine approaches will likely be needed to identify specific subsets of neuropathy symptoms and deficits in patients, and determine the most impactful treatment. Overall, these two interventions have the potential to provide meaningful relief for patients with DPN and provide new avenues to identify new therapeutic targets.

Inhibiting apoptosis of Schwann cell under the high-glucose condition: A promising approach to treat diabetic peripheral neuropathy using Chinese herbal medicine

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes. Glycemic control and lifestyle alterations cannot prevent the development of DPN; therefore, investigating effective treatments for DPN is crucial. Schwann cells (SCs) maintain the physiological function of peripheral nerves and promote the repair and regeneration of injured nerves. Inhibiting the apoptosis of SCs through various pathological pathways in a high-glucose environment plays an important role in developing DPN. Therefore, inhibiting the apoptosis of SCs can be a novel treatment strategy for DPN. Previous studies have indicated the potential of Chinese herbal medicine (CHM) in treating DPN. In this study, we have reviewed the effects of CHM (both monomers and extracts) on the apoptosis of SCs by interfering with the production of advanced glycation end products, oxidative stress, and endoplasmic reticulum stress pathological pathways. This review will demonstrate the potentialities of CHM in inhibiting apoptosis in SCs, providing new insights and perspectives for treating DPN.

Diabetic Neuropathy: Review on Molecular Mechanisms

Diabetic mellitus is a worldwide endocrine and metabolic disorder with insulin insensitivity or deficiency or both whose prevalence could rise up to 592 million by 2035. Consistent hyperglycemia leads to one of the most common comorbidities like Diabetic Peripheral Neuropathy (DPN). DPN is underlined with unpleasant sensory experience, such as tingling and burning sensation, hyperalgesia, numbness, etc. Globally, 50-60% of the diabetic population is suffering from such symptoms as microvascular complications. Consistent hyperglycemia during DM causes activation/inhibition of various pathways playing important role in the homeostasis of neurons and other cells. Disruption of these pathways results into apoptosis and mitochondrial dysfunctions, causing neuropathy. Among these, pathways like Polyol and PARP are some of the most intensively studied ones whereas those like Wnt pathway, Mitogen activated protein kinase (MAPK), mTOR pathway are comparatively newly discovered. Understanding of these pathways and their role in pathophysiology of DN underlines a few molecules of immense therapeutic value. The inhibitors or activators of these molecules can be of therapeutic importance in the management of DPN. This review, hence, focuses on these underlying molecular mechanisms intending to provide therapeutically effective molecular targets for the treatment of DPN.

Diminished schwann cell repair responses play a role in delayed diabetes-associated wound healing

Diabetes mellitus is the most common metabolic disease associated with impaired wound healing. Recently, Schwann cells (SCs), the glia of the peripheral nervous system, have been suggested to accelerate normal skin wound healing. However, the roles of SCs in diabetic wound healing are not fully understood. In this study, Full-thickness wounds were made in the dorsal skin of C57/B6 mice and db/db (diabetic) mice. Tissue samples were collected at different time points, and immunohistochemical and immunofluorescence analyses were performed to detect markers of de-differentiated SCs, including myelin basic protein, Sox 10, p75, c-Jun, and Ki67. In addition, in vitro experiments were performed using rat SC (RSC96) and murine fibroblast (L929) cell lines to examine the effects of high glucose conditions (50 mM) on the de-differentiation of SCs and the paracrine effects of SCs on myofibroblast formation. Here, we found that, compared with that in normal mice, wound healing was delayed and SCs failed to rapidly activate a repair program after skin wound injury in diabetic mice. Furthermore, we found that SCs from diabetic mice displayed functional impairments in cell de-differentiation, cell-cycle re-entry, and cell migration. In vitro, hyperglycemia impaired RSC 96 cell de-differentiation, cell-cycle re-entry, and cell migration, as well as their paracrine effects on myofibroblast formation, including the secretion of TGF-β and Timp1. These results suggest that delayed wound healing in diabetes is due in part to a diminished SC repair response and attenuated paracrine effects on myofibroblast formation.

Protective effect of selenium on vincristine-induced peripheral neuropathy in PC12 cell line

Vincristine-induced peripheral neuropathy (VIPN) is the main side effect and major reason for neuropathic pain in cancer survivors treated with vincristine. Vincristine, a chemotherapeutic antimitotic drug, is used frequently in combination chemotherapy. The primary purpose of the current study was to assess the protective effect of sodium selenite (SSe) on VIPN in vitro. Cytotoxicity effects of vincristine were evaluated using PC12 cells as a neuronal model. The cell culture studies were conducted in three groups based on the various treatments, including vincristine, SSe, and co-exposure to both compositions. Cell viability and cell cycle analyses were performed using MTT assay and flow cytometry, respectively. The level of mRNA expression of Bax and Bcl-2 was determined using qRT-PCR. According to the results, vincristine decreased the survival rate of PC12 cells. After 24 and 48 h exposure to different concentrations of vincristine (0.1-20 μΜ), the survival rate of PC12 cells decreased as compared to the control group. The results showed that treatment with 5 μΜ of vincristine resulted in apoptosis of PC12 cells. Interestingly,co-incubation of these cells with SSe significantly reduced the cell damage induced by vincristine. Furthermore, vincristine induced the inhibition of the G2 phase in PC 12 cells, and using SSe in combination with vincristine eliminated the inhibition of the cell cycle in the G2 phase. Briefly, our in vitro preliminary study showed that SSe might protect PC12 cells from vincristine-induced peripheral neuropathy during chemotherapy.

An update on molecular mechanisms of curcumin effect on diabetes

Owing to its prevalent nature, diabetes mellitus has become one of the most serious endocrine illnesses affecting a patient's quality of life due to the manifestation of side effects such as cardiovascular diseases, retinopathy, neuropathy, and nephropathy. Curcumin ((1E, 6E) 21, 7-bis (4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione), a major compound of turmeric, has been used in conventional medicine because of its safe nature and cost-effectiveness to meliorate diabetes and its comorbidities. These effects have also been observed in rodent models of diabetes resulting in a reduction of glycemia and blood lipids. Both the preventive and therapeutic activities of this compound are due to its antioxidant and anti-inflammatory characteristics. Furthermore, preclinical outcomes and clinical investigation demonstrate that the use of curcumin neutralizes insulin resistance, obesity, and hyperglycemia. Despite the many benefits of curcumin, its two limiting factors, solubility and bioavailability, remain a challenge for researchers; therefore, several methods such as drug formulation, nano-drug delivery, and the use of curcumin analogs have been developed to deliver curcumin and increase its bioavailability. PRACTICAL APPLICATIONS: The rise of people with type 2 diabetes has become a major concern at the global healthcare level. The best diabetes treatments today are anti-diabetic drug administration, lifestyle-related interventions (such as healthy eating and daily physical activity), arterial pressure detection, and fat control. The polyphenol curcumin, found in turmeric, can promote health by acting on a variety of cellular signaling pathways. This review article discusses curcumin and its role in the treatment of diabetes.

Sustainable Release of Propranolol Hydrochloride Laden with Biconjugated-Ufasomes Chitosan Hydrogel Attenuates Cisplatin-Induced Sciatic Nerve Damage in In Vitro/In Vivo Evaluation

Peripheral nerve injuries significantly impact patients’ quality of life and poor functional recovery. Chitosan–ufasomes (CTS–UFAs) exhibit biomimetic features, making them a viable choice for developing novel transdermal delivery for neural repair. This study aimed to investigate the role of CTS–UFAs loaded with the propranolol HCl (PRO) as a model drug in enhancing sciatica in cisplatin-induced sciatic nerve damage in rats. Hence, PRO–UFAs were primed, embedding either span 20 or 60 together with oleic acid and cholesterol using a thin-film hydration process based on full factorial design (24). The influence of formulation factors on UFAs’ physicochemical characteristics and the optimum formulation selection were investigated using Design-Expert® software. Based on the optimal UFA formulation, PRO–CTS–UFAs were constructed and characterized using transmission electron microscopy, stability studies, and ex vivo permeation. In vivo trials on rats with a sciatic nerve injury tested the efficacy of PRO–CTS–UFA and PRO–UFA transdermal hydrogels, PRO solution, compared to normal rats. Additionally, oxidative stress and specific apoptotic biomarkers were assessed, supported by a sciatic nerve histopathological study. PRO–UFAs and PRO–CTS–UFAs disclosed entrapment efficiency of 82.72 ± 2.33% and 85.32 ± 2.65%, a particle size of 317.22 ± 6.43 and 336.12 ± 4.9 nm, ζ potential of −62.06 ± 0.07 and 65.24 ± 0.10 mV, and accumulatively released 70.95 ± 8.14% and 64.03 ± 1.9% PRO within 6 h, respectively. Moreover, PRO–CTS–UFAs significantly restored sciatic nerve structure, inhibited the cisplatin-dependent increase in peripheral myelin 22 gene expression and MDA levels, and further re-established sciatic nerve GSH and CAT content. Furthermore, they elicited MBP re-expression, BCL-2 mild expression, and inhibited TNF-α expression. Briefly, our findings proposed that CTS–UFAs are promising to enhance PRO transdermal delivery to manage sciatic nerve damage.

Folate-functionalized SMMC-7721 liver cancer cell membrane-cloaked paclitaxel nanocrystals for targeted chemotherapy of hepatoma

In this study, we prepared a folic acid-functionalized SMMC-7721 liver cancer cell membrane (CM)-encapsulated paclitaxel nanocrystals system (FCPN) for hepatoma treatment. Transmission electron microscopy (TEM) characterization showed that FCPN was irregular spherical shapes with a particle size larger than 200 nm and a coated thickness of approximately 20 nm. In an in vitro release experiment, FCPN indicated a slowly release effect of paclitaxel (PTX). Cell experiments demonstrated that FCPN was taken up by SMMC-7721 cells and significantly inhibited the proliferation of SMMC-7721 cells, which illustrated that FCPN had good targeting ability compared with PN and CPN. According to the results of in vivo animal experiments, FCPN significantly inhibited tumor growth. Tissue distribution experiments proved that FCPN could accumulate significantly in tumor tissues, which further explained why FCPN had good targeting ability. These results clearly suggested that folate-functionalized homotypic CM bionic nanosystems might represent a very valuable method for liver cancer treatment in the future.

Neuroprotective effects of novel compound Tozan on cognition, neurogenesis and apoptosis in diabetes

Background

Cognitive impairment is a serious complication of diabetes that manifests as an impairment of spatial memory and learning ability. Its pathogenesis is unclear, and effective therapeutic drugs are very limited. Our group designed and synthesized a novel compound named 3-p-tolyl-9H-xanthen-9-one (Tozan). In this study, we sought to investigate the effects and mechanism of Tozan on diabetic cognitive impairment.

Methods

Methylglyoxal (MG)-induced SH-SY5Y cells and streptozotocin (STZ)-induced type 1 diabetic mice were treated with Tozan. Methyl thiazolul tetrazolium (MTT) and lactate dehydrogenase (LDH) were used to test cytotoxicity. Morris water maze (MWM) and Y-maze tests were used to evaluate cognitive function. Immunofluorescence and western blot analyses were used to evaluate neurogenesis, apoptosis, and signal transduction pathway-related proteins. In addition, Lentivirus (LV)-estrogen receptor beta (ERβ)-ribonucleic acid interference (RNAi) was used to knockdown the ERβ gene in SH-SY5Y cells.

Results

We found that Tozan ameliorated MG-induced cytotoxicity in SH-SY5Y cells, improved cognitive dysfunction in STZ-induced type 1 diabetic mice, increased neurogenesis, and prevented apoptotic responses in vitro and in vivo. Importantly, Tozan (2, 4, and 8 mg/kg) mediated phosphatidylinositol-3-kinase and protein kinase B cAMP-response element binding protein (PI3K/Akt-CREB) signaling by activating membrane ERβ, and a high dose of Tozan (8 mg/kg) mediated CREB signaling by activating nuclear ERβ in the hippocampus. Notably, Tozan did not have an anti-apoptosis and regeneration protective role in ERβ gene knockdown cells.

Conclusions

Our study demonstrates Tozan’s contributions to and role in cognition, neurogenesis, and apoptosis in diabetes, and lays an experimental foundation for the development of new anti-diabetic cognitive impairment drugs.

NLGN3 Upregulates Expression of ADAM10 to Promote the Cleavage of NLGN3 via Activating the LYN Pathway in Human Gliomas

The neuron derived synaptic adhesion molecular neuroligin-3 (NLGN3) plays an important role in glioma growth. While the role of autocrine NLGN3 in glioma has not been well-studied. The expression of NLGN3 in glioma was detected using immunohistochemistry. We further explored its function and regulatory mechanism in U251 and U87 cells with high expression of NLGN3. Knockdown of endogenous NLGN3 significantly reduced the proliferation, migration, and invasion of glioma cells and down-regulated the activity of the PI3K-AKT, ERK1/2, and LYN signaling pathways. In comparison, overexpression of NLGN3 yielded opposite results. Our results further demonstrate that LYN functions as a feedback mechanism to promote NLGN3 cleavage. This feedback regulation was achieved by upregulating the ADAM10 sheddase responsible for NLGN3 cleavage. Inhibition of ADAM10 suppressed the proliferation, migration, and invasion of glioma cells; oppositely, the expression of ADAM10 was correlated with a higher likelihood of lower grade glioma (LGG) in the brain. Our study demonstrates that glioma-derived NLGN3 promotes glioma progression by upregulating activity of LYN and ADAM10, which in turn promote NLGN3 cleavage to form a positive feedback loop. This pathway may open a potential therapeutic window for the treatment of human glioma.

Comparison of Conduits Fabricated by Fresh and Predegenerated Skeletal Muscles for Peripheral Nerve Repairing

ABSTRACT

Reconstruction of peripheral nerve injury remains a challenge for clinical medicine. Previous reports have confirmed that external oblique muscle-fabricated nerve conduit (EMC) could effectively be used to promote peripheral nerve regeneration. In this study, we compared between conduits fabricated from fresh muscle and conduits fabricated from predegenerated muscle for the repair of peripheral nerve defects in a mouse sciatic nerve transection model. We found that the number, diameter, and myelin sheath thickness of the myelinated nerve fibers of the regenerative nerve in the EMC group were larger than those of the predegenerated-EMC (P-EMC) group eight weeks after surgery. The sciatic function index and gastrocnemius wet-weight mass ratio in the EMC group were higher than those in the P-EMC group. The Bcl-2/Bax ratio and the number of Schwann cell nucleus in the proximal nerve stumps in the EMC group were greater than those in the P-EMC group. In conclusion, our results confirmed that the use of fresh skeletal muscle nerve conduit increased the Bcl-2/Bax ratio and promoted the survival of Schwann cells of the proximal nerve stump compared with that of predegenerated skeletal muscle nerve conduits, thus achieving better functional recovery after sciatic nerve defect.

TXNIP, a novel key factor to cause Schwann cell dysfunction in diabetic peripheral neuropathy, under the regulation of PI3K/Akt pathway inhibition-induced DNMT1 and DNMT3a overexpression

Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes mellitus (DM) and the dysfunction of Schwann cells plays an important role in the pathogenesis of DPN. Thioredoxin-interacting protein (TXNIP) is known as an inhibitor of thioredoxin and associated with oxidative stress and inflammation. However, whether TXNIP is involved in dysfunction of Schwann cells of DPN and the exact mechanism is still not known. In this study, we first reported that TXNIP expression was significantly increased in the sciatic nerves of diabetic mice, accompanied by abnormal electrophysiological indexes and myelin sheath structure. Similarly, in vitro cultured Schwann cells TXNIP was evidently enhanced by high glucose stimulation. Again, the function experiment found that knockdown of TXNIP in high glucose-treated RSC96 cells led to a 4.12 times increase of LC3-II/LC3-I ratio and a 25.94% decrease of cleaved caspase 3/total caspase 3 ratio. Then, DNA methyltransferase (DNMT) inhibitor 5-Aza has been reported to benefit Schwann cell in DPN, and here 5-Aza treatment reduced TXNIP protein expression, improved autophagy and inhibited apoptosis in high glucose-treated RSC96 cells and the sciatic nerves of diabetic mice. Furthermore, DNMT1 and DNMT3a upregulation were found to be involved in TXNIP overexpression in high glucose-stimulated RSC96 cells. Silencing of DNMT1 and DNMT3a effectively reversed high glucose-enhanced TXNIP. Moreover, high glucose-inhibited PI3K/Akt pathway led to DNMT1, DNMT3a, and TXNIP upregulation in RSC96 cells. Knockdown of DNMT1 and DNMT3a prevented PI3K/Akt pathway inhibition-caused TXNIP upregulation in RSC96 cells. Finally, in vivo knockout of TXNIP improved nerve conduction function, increased autophagosome and LC3 expression, and decreased cleaved Caspase 3 and Bax expression in diabetic mice. Taken together, PI3K/Akt pathway inhibition mediated high glucose-induced DNMT1 and DNMT3a overexpression, leading to cell autophagy inhibition and apoptosis via TXNIP protein upregulation in Schwann cells of DPN.

Ozone induces tolerance against cardiomyocytes oxygen-glucose deprivation/reperfusion through inhibition of autophagy pathway

Previous studies have reported that excess activation of autophagy in cardiomyocytes is associated with an increase in myocardial oxygen-glucose deprivation/reperfusion (OGD/R) injury. Ozone therapy affords significant cardio-protection against myocardial OGD/R injury. The present study was designed to determine whether ozone-induced tolerance to myocardial OGD/R injury was mediated by inhibiting autophagy. Subsequently, the rat cardio myoblast H9C2 cell line was used in the present study. A model of H9C2 cells under OGD/R was established. The cells were incubated with different concentrations of ozone (10-60 µg/ml) during reperfusion. Furthermore, to investigate the role of autophagy in OGD/R-induced injury, the autophagy inducer and inhibitor were applied. Cell viability was detected by Cell Counting kit-8 assay. Cell apoptosis was evaluated by flow cytometry. Oxidative stress was examined by superoxide dismutase, lactate dehydrogenase and malondialdehyde levels. The expressions of apoptosis regulator B-cell lymphoma-2 (Bcl-2), Bcl-2 associated X protein (BAX), cleaved caspase-3, markers of autophagy microtuble-associated protein 1 light chain 3 (LC3), autophagy-related protein 5 (Atg5) and Beclin-1 were measured by western blot analysis. As a result, OGD/R notably decreased cell viability and induced apoptosis in H9C2 cells, while ozone (10-40 µg/ml) reversed the noxious effects of OGD/R on H9C2 cells, and 20 µg/ml ozone was the most effective. Ozone inhibited the decrease in the ratio of Bcl-2/BAX and the expression of cleaved caspase-3, and inhibited the increase in the ratio of LC3-II/LC3-I and the expression of Atg5 and Beclin-1 elicited by OGD/R, as well as dose-dependently preventing OGD/R-induced oxidative stress. Furthermore, rapamycin markedly reversed the effects of ozone (20 µg/ml) on OGD/R-induced expression of autophagy marker proteins and 3-methyladenine further improved the effect of ozone. Taken together, the results of the present study provided a credible mechanism by which ozone treatment at low concentrations could protect the myocardium from OGD/R-induced injury by inhibiting autophagy.

Pharmacological effects and mechanisms of muscone

Musk, the dried secretion from the preputial follicles of the male musk deer (genus Moschus), possesses various pharmacological activities and has been used extensively in traditional Chinese medicine for thousands of years. Muscone is the main active ingredient of musk and exerts pharmacological effects similar to those of musk. Although muscone was notably used to treat various disorders and diseases, such as neurological disorders, chronic inflammation and ischemia-reperfusion injury, most of the mechanisms of the pharmacological action of muscone remain unclear because of slow progress in research before the 21st century. In recent years, the pharmacological activities and mechanisms of muscone have been clarified. The present article summarizes the pharmacological and biological studies on cerebrovascular disease, cardiovascular disease, neurological effects, cancer and others and the associated mechanisms of the action of muscone to date.

Curcumin anti-diabetic effect mainly correlates with its anti-apoptotic actions and PI3K/Akt signal pathway regulation in the liver

This study aimed to investigate the therapeutic effect of curcumin on type 2 diabetes and its underlying mechanisms. A type 2 diabetes mellitus rat model was established by providing high-fat diet and low doses of streptozotocin. Type 2 diabetes mellitus rats were treated with low dose and high dose of curcumin for 8 weeks. The results showed that high-dose curcumin significantly reduced fasting blood glucose, total cholesterol, triglyceride, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, alanine aminotransferase, and aspartate transaminase, liver coefficient, and malondialdehyde levels, and BCL2-Associated X expression in the type 2 diabetes mellitus rats. High-dose curcumin increased the levels of liver superoxide dismutase, catalase, and glutathione; as well as the expression of liver B-cell lymphoma-2, phosphatidylinositol 3-kinase, phosphorylated phosphatidylinositol 3-kinase, protein kinase B, and phosphorylated protein kinase B in type 2 diabetes mellitus rats. Furthermore, it ameliorated the histological structure of the liver and pancreas in diabetes mellitus model rats. However, low-dose curcumin had no significant effect on diabetes mellitus model rats. The results suggest that adequate doses of curcumin controls type 2 diabetes mellitus development as well as the mechanism involved in its anti-apoptotic actions and phosphatidylinositol 3-hydroxy kinase/protein kinase B signal pathway regulation in the liver.

Loganin Attenuates High Glucose-Induced Schwann Cells Pyroptosis by Inhibiting ROS Generation and NLRP3 Inflammasome Activation

Diabetic peripheral neuropathy (DPN) is caused by hyperglycemia, which induces oxidative stress and inflammatory responses that damage nerve tissue. Excessive generation of reactive oxygen species (ROS) and NOD-like receptor protein 3 (NLRP3) inflammasome activation trigger the inflammation and pyroptosis in diabetes. Schwann cell dysfunction further promotes DPN progression. Loganin has been shown to have antioxidant and anti-inflammatory neuroprotective activities. This study evaluated the neuroprotective effect of loganin on high-glucose (25 mM)-induced rat Schwann cell line RSC96 injury, a recognized in vitro cell model of DPN. RSC96 cells were pretreated with loganin (0.1, 1, 10, 25, 50 μM) before exposure to high glucose. Loganin’s effects were examined by CCK-8 assay, ROS assay, cell death assay, immunofluorescence staining, quantitative RT–PCR and western blot. High-glucose-treated RSC96 cells sustained cell viability loss, ROS generation, NF-κB nuclear translocation, P2 × 7 purinergic receptor and TXNIP (thioredoxin-interacting protein) expression, NLRP3 inflammasome (NLRP3, ASC, caspase-1) activation, IL-1β and IL-18 maturation and gasdermin D cleavage. Those effects were reduced by loganin pretreatment. In conclusion, we found that loganin’s antioxidant effects prevent RSC96 Schwann cell pyroptosis by inhibiting ROS generation and suppressing NLRP3 inflammasome activation.

SPP1 promotes Schwann cell proliferation and survival through PKCα by binding with CD44 and αvβ3 after peripheral nerve injury

Background

Schwann cells (SCs) play a crucial role in Wallerian degeneration after peripheral nerve injury. The expression of genes in SCs undergo a series of changes, which greatly affect the proliferation and apoptosis of SCs as well as the fate of peripheral nerve regeneration. However, how do these genes regulate the proliferation and apoptosis of SCs remains unclear.

Results

SPP1 and PKCα were found upregulated after human median peripheral nerve injury, which promoted SCs proliferation and survival. The promoted proliferation and inhibited apoptosis by SPP1 were blocked after the treatment of PKCα antagonist Gö6976. Whereas, the inhibited proliferation and enhanced apoptosis induced by silence of SPP1 could be rescued by the activation of PKCα, which suggested that SPP1 functioned through PKCα. Moreover, both CD44 and αvβ3 were found expressed in SCs and increased after peripheral nerve injury. Silence of CD44 or β3 alleviated the increased proliferation and inhibited apoptosis induced by recombinant osteopontin, suggesting the function of SPP1 on SCs were dependent on CD44 and β3.

Conclusion

These results suggested that SPP1 promoted proliferation and inhibited apoptosis of SCs through PKCα signaling pathway by binding with CD44 and αvβ3. This study provides a potential therapeutic target for improving peripheral nerve recovery.

IFN‑γ induces apoptosis in human melanocytes by activating the JAK1/STAT1 signaling pathway

The present study aimed to investigate the role of janus kinase (JAK)1/STAT1 in interferon (IFN)-γ-induced apoptosis in human melanocytes. Following IFN-γ treatment, the viability of human melanocytes were analyzed using a Cell Counting Kit-8 assay and the apoptotic rate was determined using flow cytometry. Western blotting was also performed to analyze the phosphorylation levels of JAK1, JAK2 and the transcriptional factor STAT1, as well as the expression levels of Bcl-2, Bax, Bcl-2 homologous antagonist killer (Bak) and cleaved caspase-3. Finally, following the pretreatment with the STAT1 inhibitor fludarabine, human melanocytes were treated with IFN-γ and flow cytometry was used to detect the apoptotic rate. The results revealed that IFN-γ reduced the proliferation and induced the apoptosis of human melanocytes. In addition, IFN-γ treatment led to decreased expression levels of Bcl-2 and increased expression levels of Bax, Bak and cleaved caspase-3, alongside the activation of the JAK1/STAT1 signaling pathway. Conversely, the pretreatment with the STAT1 inhibitor fludarabine decreased the apoptotic rate of human melanocytes following IFN-γ induction. In conclusion, the findings of the present study suggested that IFN-γ may induce the apoptosis of human melanocytes by activating the JAK1/STAT1 signaling pathway, alongside increasing the expression levels of Bax, Bak and cleaved caspase-3, and decreasing the expression levels of Bcl-2.

The Protective Effect and Mechanism of Dexmedetomidine on Diabetic Peripheral Neuropathy in Rats

Objective

To investigate the role of dexmedetomidine (DEX) in the inhibition of diabetic peripheral neuropathy (DPN) and the protection in the nerve damage.

Methods

Eighty male Sprague-Dawley (SD) rats were randomly allocated to four groups: the control group (C group), DPN model group (DPN group), DEX-treated group (DEX group), and the yohimbine treated group (YOH group). DPN was induced by intraperitoneal administration of streptozocin (STZ) (35 mg/kg). The body weights, blood glucose level, mechanical withdrawal threshold (MWT), thermal withdrawal latency (TWL), the motor, and sensory nerve conduction velocities (MNCV and SNCV) of sciatic nerve were measured. Then the sciatic nerve was isolated for H&E staining and immunohistochemical staining. The oxidative stress makers such as malondialdehyde (MDA), superoxide-dismutase (SOD), and glutathione peroxidase (GSH-Px) and apoptosis related cytokines such as Bax, Bcl-2, and caspase-3 were estimated.

Results

There was no significant difference of the blood glucose and body weight among the DPN group, DEX group, and YOH group. H&E staining showed that DEX treatment can ameliorate the damage of sciatic nerve cells. In the DPN group, MWT, TWL, MNCV, and SNCV were significantly reduced compared with the C group (P < 0.05). In DEX group rats, MWT, TWL, MNCV, and SNCV were increased significantly (P < 0.05) compared with the DPN group and YOH group rats. Lower SOD and GSH-Px, and higher MDA were found in the DPN group compared with the C group (P < 0.01), and DEX treatment restored SOD, GSH-px, and MDA activity significantly (P < 0.01). The expression levels of Bax and caspase-3 were increased, while that of Bcl-2 was decreased significantly in the DPN group compared with the C group (P < 0.05). In the DEX group, the expression levels of Bax and caspase-3 were decreased significantly (P < 0.05), while that of Bcl-2 was increased significantly (P < 0.05) compared with the DPN group and the YOH group.

Conclusion

The results of this study demonstrated that DEX has the inhibitory and protective effects on DPN of rats. This may be associated with its antioxidative and anti-apoptosis responses.

The expression and significance of mTORC1 in diabetic retinopathy

Background

To investigate the expression and significance of mechanistic target of rapamycin complex 1(mTORC1) in diabetic retinopathy (DR), and to find new targets and new methods for the treatment of DR.

Methods

A DR rat model was prepared by general feeding combined with intraperitoneal injection of 10% streptozotocin (60 mg/kg). The rats were randomly divided into a control group (NDM group) and a diabetes group (DM group). Three months later, the degrees of retinopathy was determined using hematoxylin and eosin staining, and the levels of p-S6, VEGF, and PEDF proteins were detected by immunohistochemistry and western blotting. Human retinal capillary endothelial cells (HRCECs) were cultured in high glucose (HG) conditions, then treated with rapamycin or transfected with siTSC1.The protein levels of p-S6 were assessed by western blotting. The 5-ethynyl-2′-deoxyuridine assay was used to detect cell proliferation, and the Transwell assay was used to detect cell migration.

Results

A DM rat model was successfully developed. The expressions of p-S6 and VEGF proteins were significantly increased in the DM group (p < 0.05), and the expression of PEDF protein was significantly decreased compared with the NDM group (p < 0.05). In vitro, the p-S6 protein, as well as cell proliferation and migration, in HG induced HRCECs were increased (p < 0.05) compared with the control (normal glucose) group (p < 0.05). After transfection with siTSC1 to activate mTORC1, the expression of p-S6, as well as cell proliferation and migration, were increased. In contrast, rapamycin decreased p-S6 expression, as well as proliferation and migration, in HG induced HRCECs compared to the control group (p < 0.05).

Conclusion

mTORC1 plays an important role in DR. After activation, mTORC1 induced expression of the p-S6 protein, regulated the expressions of VEGF and PEDF proteins, and changed the proliferation and migration of endothelial cells. The mTORC1 can therefore be used as a new target,as well as in the treatment of DR.

Schwann cells apoptosis is induced by high glucose in diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes mellitus that affects approximately half of patients with diabetes. Current treatment regimens cannot treat DPN effectively. Schwann cells (SCs) are very sensitive to glucose concentration and insulin, and closely associated with the occurrence and development of type 1 diabetic mellitus (T1DM) and DPN. Apoptosis of SCs is induced by hyperglycemia and is involved in the pathogenesis of DPN. This review considers the pathological processes of SCs apoptosis under high glucose, which include the following: oxidative stress, inflammatory reactions, endoplasmic reticulum stress, autophagy, nitrification and signaling pathways (PI3K/AKT, ERK, PERK/Nrf2, and Wnt/β-catenin). The clarification of mechanisms underlying SCs apoptosis induced by high glucose will help us to understand and identify more effective strategies for the treatment of T1DM DPN.

IFN-γ/mTORC1 decreased Rab11 in Schwann cells of diabetic peripheral neuropathy, inhibiting cell proliferation via GLUT1 downregulation

Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes mellitus. Rab11 is conserved gene-regulating vesicle traffic and reported to be involved in the pathogenesis of diabetes mellitus by affecting insulin sensitivity. We aimed to investigate the role of Rab11 in the pathogenesis of DPN. In this study, Rab11 expression decreased in the sciatic nerves of diabetic mice with impaired conduction function versus those of normal mice. In vitro experiment revealed interferon-γ (IFN-γ), not high glucose and interleukin 1β was the main factor to lead to Rab11 downregulation in RSC96 cells. Again, both Rab11 knockdown and IFN-γ treatment caused cell viability inhibition and the decrease in BrdU-positive cells. In contrast, overexpression of Rab11 reversed IFN-γ-reduced cell proliferation. Furthermore, mTORC1 not mTORC2 was proven to be suppressed by IFN-γ treatment in RSC96 cells, indicated in decreased phospho-p70S6K. Inhibition of the mTORC1 pathway resulted in Rab11 expression downregulation in RSC96 cells. Activation of the mTORC1 pathway effectively prevented IFN-γ-reduced Rab11 expression in RSC96 cells. Also, glucose transporter 1 (GLUT1) was found to be downregulated in RSC96 cells with Rab11 silence and overexpression of GLUT1 reversed Rab11 blocking-caused proliferation inhibition. Taken together, our findings suggest that IFN-γ decreases Rab11 expression via the inhibition of the mTORC1 signaling pathway, causing reduced cell proliferation in Schwann cells of DPN by GLUT1 downregulation.

Muscone ameliorates diabetic peripheral neuropathy through activating AKT/mTOR signalling pathway

OBJECTIVES

Emerging evidence showed that muscone could improve chronic inflammation after myocardial infarction and protect alcohol-induced osteonecrosis of the femoral head. However, the function of muscone on diabetic peripheral neuropathy (DPN) is obscure.

METHODS

The neuronal Schwann cell RSC 96 cells were treated with 125 mmol/l glucose to simulate the cells in DPN. The RSC 96 cell viability was detected by cell counting kit-8. The RSC 96 cell cycle and apoptosis were determined by flow cytometry. The expression of marker proteins of apoptosis, autophagy and AKT/mTOR signalling pathway was assessed by Western blot.

KEY FINDINGS

We observed that after high glucose (HG) treatment, the number of cell apoptosis was increased, cell proliferation was decreased, as well as the expression of apoptosis-related proteins and autophagy-related proteins were changed. However, this phenomenon can be reversed by muscone. Meanwhile, the expression of phosphorylated AKT and mammalian target of rapamycin (mTOR) was down-regulated with HG treatment, while the expression quantity was up-regulated after disposed with muscone.

CONCLUSIONS

Our outcomes demonstrated that autophagy and apoptosis of RSC 96 cells induced by HG can be alleviated by muscone through modulating AKT/mTOR signalling pathway, suggesting that muscone might be a potential molecule with influence in connection to DPN.

The Akt/mTOR cascade mediates high glucose-induced reductions in BDNF via DNMT1 in Schwann cells in diabetic peripheral neuropathy

Brain-derived neurotropic factor (BDNF) deficiency in Schwann cells plays an important role in the pathogenesis of diabetic peripheral neuropathy (DPN). Little is known about the mechanism involved in BDNF downregulation in Schwann cells in DPN. In this study, we first confirmed downregulation of BDNF and neurotrophin 3 expression in the sciatic nerves of diabetic mice, which was accompanied by myelin sheath abnormalities. Moreover, in vitro, high glucose was revealed to cause downregulation of BDNF, but not neurotrophin 3, expression in RSC96 cells, which was accompanied by DNA hypermethylation of BDNF promoters I and II. DNMT1 was subsequently revealed to be enhanced at the mRNA and protein levels in high glucose-stimulated RSC96 cells, and inhibition of DNMT1 with 5-Aza treatment or shRNA vector transfection reversed high glucose-induced reductions in BDNF expression. Furthermore, the mTOR and upstream Akt pathways were indicated to mediate high glucose-induced DNMT1 and BDNF expression in RSC96 cells. Taken together, our results suggest that the Akt/mTOR cascade mediates high glucose-induced reductions in BDNF via DNMT1 in Schwann cells in DPN.

Effect of exosomes from adipose-derived stem cells on the apoptosis of Schwann cells in peripheral nerve injury

Aims

Recovery after peripheral nerve injury (PNI) is often difficult, and there is no optimal treatment. Schwann cells (SCs) are important for peripheral nerve regeneration, so SC‐targeting treatments have gained importance. Adipose‐derived stem cells (ADSCs) and their exosomes can promote peripheral nerve repair, but their interactions with SCs are unclear.

Methods

Purified SCs from sciatic nerve injury sites were harvested, and apoptosis and proliferation of SCs at post‐PNI 24 hours were analyzed. The effects of coculture with ADSCs and different concentrations of ADSC‐derived exosomes (ADSC‐Exo) were studied through in vitro experiments by flow cytometry, CCK8 assay, immunofluorescence staining, and histological analysis. The expression of the apoptosis‐related genes Bcl‐2 and Bax was also analyzed by qRT‐PCR.

Results

ADSC‐Exo reduced the apoptosis of SCs after PNI by upregulating the anti‐apoptotic Bcl‐2 mRNA expression and downregulating the pro‐apoptotic Bax mRNA expression. Further, it also improved the proliferation rate of SCs. This effect was confirmed by the morphological and histological findings in PNI model rats.

Conclusion

Our results present a novel exosome‐mediated mechanism for ADSC‐SC cross talk that reduces the apoptosis and promotes the proliferation of SCs and may have therapeutic potential in the future.

STAT3 phosphorylation mediates high glucose-impaired cell autophagy in an HDAC1-dependent and -independent manner in Schwann cells of diabetic peripheral neuropathy

Schwann cells are the main supportive cells of the peripheral nerves. Schwann cells suffer inhibition of autophagy under hyperglycemia treatment in diabetic peripheral neuropathy (DPN). However, the exact mechanism is still not fully elucidated. We first observed the decrease of autophagy markers (LC3-II/LC3-I, P62) in the sciatic nerves of diabetic mice vs. normal mice, accompanied with the loss of myelinated nerve fibers and abnormal myelin sheath. In line with this, LC3-II/LC3-I and P62 were also significantly reduced in high glucose-treated rat Schwann cell 96 (RSC96) cells compared with normal glucose-treated cells. Furthermore, we found that trichostatin A [an inhibitor of histone deacetylase (HDAC)] evidently improved LC3-II/LC3-I in high glucose-treated RSC96 cells, without an effect on P62 expression. Again, HDAC1 and HDAC5 were revealed to be increased in RSC96 cells stimulated with high glucose. Inhibition of HDAC1 but not HDAC5 by small hairpin RNA vector enhanced LC3-II/LC3-I in high glucose-cultured RSC96 cells. In addition, LC3-II conversion regulators [autophagy-related protein (Atg)3, Atg5, and Atg7] were detected in high glucose-treated and HDAC1-knockdown RSC96 cells, and Atg3 was proven to be the key target of HDAC1. The presuppression of Atg3 offset the improvement of LC3-II/LC3-I resulting from HDAC1 inhibition in high glucose-treated RSC96 cells. The Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway was activated in RSC96 cells treated with high glucose, which was indicated by increased STAT3 phosphorylation. Blocking STAT3 phosphorylation by chemical inhibitor AG490 induced HDAC1 down-regulation followed by increases in Atg3 and LC3-II/LC3-I. Interestingly, we also found that AG490 treatment enhanced P62 expression in high glucose-stimulated RSC96 cells. Taken together, our findings demonstrate that hyperglycemia inhibits LC3-II/LC3-I in an HDAC1-Atg3-dependent manner and decreases P62 expression in an HDAC-independent manner via the JAK-STAT3 signaling pathway in the Schwann cells of DPN.-Du, W., Wang, N., Li, F. Jia, K., An, J., Liu, Y., Wang, Y., Zhu, L., Zhao, S. Hao, J. STAT3 phosphorylation mediates high glucose-impaired cell autophagy in an HDAC1-dependent and -independent manner in Schwann cells of diabetic peripheral neuropathy.

Melatonin Prevents Oxidative Stress-Induced Mitochondrial Dysfunction and Apoptosis in High Glucose-Treated Schwann Cells via Upregulation of Bcl2, NF-κB, mTOR, Wnt Signalling Pathways

Neuropathy is a complication that affects more than 50% of long-standing diabetic patients. One of the causes of diabetes neuropathy (DN) is the apoptosis of Schwann cells due to prolonged exposure to high glucose and build-up of oxidative stress. Melatonin is a hormone that has a known antioxidant property. In this study, we investigated the protective effect of melatonin on high glucose-induced Schwann cells' apoptosis. Our results revealed that high glucose promoted apoptosis via mitochondrial-related oxidative stress and downregulated Bcl-2 family proteins in Schwann cells. In this signalling pathway, Bcl-2, Bcl-XL and Mcl-1 proteins were down-regulated while p-BAD and Puma proteins were up-regulated by high glucose treatment. Besides, we also proved that high glucose promoted apoptosis in Schwann cells through decreasing the p-NF-κB in the NF-κB signalling pathway. Key regulators of mTOR signalling pathway such as p-mTOR, Rictor and Raptor were also down-regulated after high glucose treatment. Additionally, high glucose treatment also decreased the Wnt signalling pathway downstream proteins (Wnt 5a/b, p-Lrp6 and Axin). Our results showed that melatonin treatment significantly inhibited high glucose-induced ROS generation, restored mitochondrial membrane potential and inhibited high glucose-induced apoptosis in Schwann cells. Furthermore, melatonin reversed the alterations of protein expression caused by high glucose treatment. Our results concluded that melatonin alleviates high glucose-induced apoptosis in Schwann cells through mitigating mitochondrial-related oxidative stress and the alterations of Bcl-2, NF-κB, mTOR and Wnt signalling pathways.

Paip1 Indicated Poor Prognosis in Cervical Cancer and Promoted Cervical Carcinogenesis

Purpose

This study was aimed to investigate the role of poly(A)-binding protein-interacting protein 1 (Paip1) in cervical carcinogenesis.

Materials and Methods

The expression of Paip1 in normal cervical epithelial tissues and cervical cancer (CC) tissues were detected by immunohistochemistry. In vivo and in vitro assays were performed to validate effect of Paip1 on CC progression.

Results

Paip1 was found to be up-regulated in CC, which was linked with shorter survival. Knockdown of Paip1 inhibited cell growth, induced apoptosis and cell cycle arrest in CC cells, whereas its overexpression reversed these effects. The in vivo tumor model confirmed the pro-tumor role of Paip1 in CC growth.

Conclusion

Altogether, the investigation demonstrated the clinical significance of Paip1 expression, which prompted that the up-regulated of Paip1 can presumably be a potential prognostic and progression marker for CC.

1,25-(OH)2D3 protects Schwann cells against advanced glycation end products-induced apoptosis through PKA-NF-κB pathway

AIMS

To explore the effect and mechanism of 1, 25-(OH)₂D₃ on Schwann cell apoptosis induced by advanced glycation end products.

MAIN METHODS

Schwann cells, isolated from rodent sciatic nerve were incubated with AGE-modified bovine serum albumin(AGE) to mimic diabetic conditions and 1,25-(OH)₂D₃ was used as protector. Cell apoptosis was detected by PI/Annexin-V staining, caspase 3 activity assay and western blotting for caspase 3 and PARP. The activation of protein kinase A (PKA) and nuclear factor kappa-B (NF-κB) was evaluated by western blot. Immunofluorescent staining was used for intercellular location of NF-κB. Cytokine secretion was evaluated by enzyme-linked immunosorbent assay.

KEY FINDINGS

Schwann cell apoptosis accelerated after incubating with AGE. However, if combining 1,25-(OH)₂D₃ with AGE, apoptosis decreased significantly. 1,25-(OH)₂D₃ enhanced PKA activity, but inhibited AGE-induced nuclear translocation of NF-κB. Furthermore, PKA activator (8-bromoadenoside cyclic adenoside monophosphate, 8-Br-cAMP) or NF-κB inhibitor (caffeic acid phenethyl ester, CAPE) could reduce the apoptosis, decreased cleaved caspase 3 and cleaved PARP, suggesting the involvement of PKA and NF-κB pathways in the protection of 1,25-(OH)₂D₃ on Schwann cells. Moreover, 8-Br-cAMP and CAPE could inhibit AGE-induced secretion of interleukin(IL)-1β, prostaglandin E2(PEG2) and cyclooxygenase 2(COX2). Interestingly, 8-Br-cAMP decreased phospho-NF-κB and inhibited nucleus translocation of NF-κB. It hinted at the regulation of PKA to NF-κB. Finally, a pre-treatment of H-89 (an inhibitor of PKA) could block the protection of 1,25-(OH)₂D₃ on cell apoptosis. In conclusion, 1,25-(OH)₂D₃ could protect Schwann cell against AGE-induced apoptosis through PKA/NF-κB pathway.

SIGNIFICANCE

These findings provide experimental rationales for using vitamin D for diabetic neuropathy.

Lipoxin A4 receptor agonist BML-111 induces autophagy in alveolar macrophages and protects from acute lung injury by activating MAPK signaling

Background

Acute lung injury (ALI) is a life-threatening lung disease where alveolar macrophages (AMs) play a central role both in the early phase to initiate inflammatory responses and in the late phase to promote tissue repair. In this study, we examined whether BML-111, a lipoxin A4 receptor agonist, could alter the phenotypes of AM and thus present prophylactic benefits for ALI.

Methods

In vitro, isolated AMs were treated with lipopolysaccharide (LPS) to induce ALI. In response to BML-111 pre-treatment, apoptosis and autophagy of AMs were examined by flow cytometry, and by measuring biomarkers for each process. The potential involvement of MAPK1 and mTOR signaling pathway was analyzed. In vivo, an LPS-induced septic ALI model was established in rats and the preventative significance of BML-111 was assessed. On the cellular and molecular levels, the pro-inflammatory cytokines TNF-α and IL-6 from bronchoalveolar lavage were measured by ELISA, and the autophagy in AMs examined using Western blot.

Results

BML-111 inhibited apoptosis and induced autophagy of AMs in response to ALI inducer, LPS. The enhancement of autophagy was mediated through the suppression of MAPK1 and MAPK8 signaling, but independent of mTOR signaling. In vivo, BML-111 pre-treatment significantly alleviated LPS-induced ALI, which was associated with the reduction of apoptosis, the dampened production of pro-inflammatory cytokines in the lung tissue, as well as the increase of autophagy of AMs.

Conclusions

This study reveals the prophylactic significance of BML-111 in ALI and the underlying mechanism: by targeting the MAPK signaling but not mTOR pathway, BML-111 stimulates autophagy in AMs, attenuates the LPS-induced cell apoptosis, and promotes the resolution of ALI.

Folate-Functionalized Mesoporous Hollow SnO2 Nanofibers as a Targeting Drug Carrier to Improve the Antitumor Effect of Paclitaxel for Liver Cancer Therapy

In this study, we prepared PTX-loaded mesoporous hollow SnO₂ nanofibers conjugated with folic acid (SFNFP) for liver cancer therapy. According to SEM and TEM characterization, SFNF showed a mesoporous hollow structure. The average outer diameter was 200 nm, and the wall thickness was 50 nm. The DSC and XRD study showed that PTX in the channels of nanofibers was present in an amorphous state. The in vitro release experiments demonstrated that SFNF could efficiently improve the dissolution rate of PTX. Both in vitro cell experiments and in vivo antitumor experiments showed that SFNFP could efficiently inhibit the growth of liver cancer cells. Therefore, SFNF is a promising targeting antitumor drug delivery carrier.

Emerging role of Unfolded Protein Response (UPR) mediated proteotoxic apoptosis in diabetes

Endoplasmic reticulum (ER) is a crucial single membrane organelle that acts as a quality control system for cellular proteins as it is intricately involved in their synthesis, folding and trafficking to the respective targets. Type 2 diabetes is characterized by enhanced blood glucose level that promotes insulin resistance and hampers cellular glucose metabolism. Hyperglycemia provokes mitochondrial ROS production and glycation of proteins which exert a tremendous load on ER for conventional refolding of misfolded/unfolded and nascent proteins that perturb ER homeostasis resulting in apoptotic cell death. Impairment in ER functions is suspected to be through specific ER membrane-bound proteins known as Unfolded Protein Response (UPR) sensor proteins. Conformational changes in these proteins induce oligomerization and cross-autophosphorylation which facilitate processes required for the restoration of ER homeostatic imbalance. Multiple studies have reported the involvement of UPR mediated autophagy and apoptotic pathways in the progression of metabolic disorders including diabetes, cardiac ischemia/reperfusion injury and hypoxia-mediated cell death. In this review, the involvement of UPR pathways in the progression of diabetes associated complications have been addressed, which underscores molecular crosstalks during neuropathy, nephropathy, hepatic injury and retinopathy. A better understanding of these molecular interventions may reveal advanced therapeutic approaches for preventing diabetic comorbidities. The article also highlights the importance of phytochemicals that are emerging as novel ER stress inhibitors and are being explored for targeted interaction in preventing cell death responses during diabetes.

Role of miR-9-5p in preventing peripheral neuropathy in patients with rheumatoid arthritis by targeting REST/miR-132 pathway

MicroRNAs (miRNAs) are found to play a key role in neural cell differentiation, peripheral nerve injury, and rheumatoid arthritis (RA). However, no study has yet been conducted highlighting their role in RA-induced peripheral neuropathy. Here, we investigated the role of miRNAs in RA-induced peripheral neuropathy. Levels of six miRNAs were detected in serum collected from 15 patients with RA and peripheral neuropathy and 16 patients with RA. In vitro, Schwann cells were treated with 0.1 ng/mL IL-6 and 20 ng/mL TNF-α. The expression level of miR-9-5p and its association with the repressor element-1 silencing transcription factor (REST) were investigated. The roles of miR-9-5p and REST in Schwann cell injury were examined after transfection of miR-9-5p mimics or REST siRNA. In patients with RA and peripheral neuropathy, serum miR-9-5p was significantly downregulated when compared with RA. In IL-6- and TNF-α-stimulated Schwann cells, apoptosis was induced, while the cell viability and level of miR-9-5p were inhibited. A significantly negative correlation was observed between miR-9-5p and REST. Transfection of miR-9-5p mimics and REST siRNA significantly reversed the inhibition of cell viability and induction of apoptosis caused by IL-6 and TNF-α. In addition, overexpression of miR-9-5p upregulated the expression of miR-132, miRNA targeting E1A binding protein EP300 (EEP300), phosphatase and tensin homolog (PTEN) and forkhead box O3 (FOXO3). These results showed that Schwann cells were protected by miR-9-5p from inflammatory damage by targeting REST/miR-132 pathway, which could provide new targets for treatment of RA-induced peripheral neuropathy.

Griffipavixanthone induces apoptosis of human breast cancer MCF-7 cells in vitro

BACKGROUND

Griffipavixanthone (GPX) is a compound extracted from Garcinia oblongifolia Champ. But, no research has yet been done about the effect of GPX on breast cancer.

METHODS

We evaluated the proliferation of human breast cancer cells by CCK-8 assay and apoptosis by Annexin V (AV)-FITC and PI double staining. We used transwell assay to indicate the invasion and migration of MCF-7. To explore the molecular mechanism of GPX, we detected the mRNA and protein expression using qRT-PCR and Western blot.

RESULTS

In this study, we evaluated if GPX could inhibit the proliferation of human breast cancer cell MCF-7 and T-47D with IC50 value of 9.64 ± 0.12 µM and 10.2 1 ± 0.38 µM at 48 h. And the IC50 value of MCF-10A is 32.11 ± 0.21 µM, which showed GPX had a tiny side effect for normal breast cells. Annexin V (AV)-FITC and PI double staining demonstrated firmly the apoptosis of MCF-7 resulting from GPX. Transwell assay indicated that GPX inhibited the invasion and migration of MCF-7. In addition, we found GPX cleaved caspase-8/9 and PARP, which play important roles in apoptotic pathway. Furthermore, through the Western blot assay, GPX increased the level of pro-apoptosis protein Bax and cytochrome C. On the contrary, GPX decreased the level of anti-apoptosis protein Bcl-2. Moreover, GPX increased the mRNA and protein expression level of p53 and its target genes, which indicated that GPX induced MCF-7 cell apoptosis by up-regulating p53 and Bax expression while suppressing Bcl-2 expression.

CONCLUSION

All the results showed that GPX induces MCF-7 cell apoptosis and could be considered as a potential drug for breast cancer.

Characterization of diabetic neuropathy progression in a mouse model of type 2 diabetes mellitus

Diabetes mellitus (DM) is one of most common chronic diseases with an increasing incidence in most countries. Diabetic neuropathy (DN) is one of the earliest and main complications of diabetic patients, which is characterized by progressive, distal-to-proximal degeneration of peripheral nerves. The cellular and molecular mechanisms that trigger DN are highly complex, heterogeneous and not completely known. Animal models have constituted a valuable tool for understanding diabetes pathophysiology; however, the temporal course of DN progression in animal models of type 2 diabetes (T2DM) is not completely understood. In this work, we characterized the onset and progression of DN in BKS diabetic (db/db) mice, including the main functional and histological features observed in the human disease. We demonstrated that diabetic animals display progressive sensory loss and electrophysiological impairments in the early-to-mid phases of the disease. Furthermore, we detected an early decrease in intraepidermal nerve fiber (IENF) density in 18-week-old diabetic mice, which is highly associated with sensory loss and constitutes a reliable marker of DN. Other common histological parameters of DN – like Schwann cells apoptosis and infiltration of CD3⁺ cells in the sciatic nerve – were altered in mid-to-late phases of the disease. Our results support the general consensus that DN evolves from initial functional to late structural changes. This work aimed to characterize the progression of DN in a reliable animal model sharing the main human disease features, which is necessary to assess new therapies for this complex disease. Finally, we also aimed to identify an effective temporal window where these potential treatments could be successfully applied.

Summary: We characterized the main functional and structural diabetic neuropathy features during early-to-late phases of type 2 diabetes mellitus. This study aimed to identify a therapeutic window for new treatments.