Allicin inhibits tubular epithelial-myofibroblast transdifferentiation under high glucose conditions in vitro

Allicin Ameliorated High-glucose Peritoneal Dialysis Solution-induced Peritoneal Fibrosis in Rats via the JAK2/STAT3 Signaling Pathway

Peritoneal fibrosis (PF) is one of the most serious complications of peritoneal dialysis (PD) and is the greatest obstacle to the clinical application of PD. Chinese herbal monomers have been effective in the prevention and treatment of PF. The aim of this study was to observe the effect of allicin on PF in rats induced by high glucose and to investigate its molecular mechanism of action. A rat model of PF was established by using a 4.25% glucose-based standard peritoneal dialysis solution. The degree of peritoneal pathological damage was assessed by Hematoxylin and eosin (H&E) staining. Peritoneal collagen deposition was detected by Masson's trichrome staining. The levels of Interleukin-6 (IL-6), Tumor necrosis factor-α (TNF-α), Interleukin-1β (IL-1β) and monocyte chemoattractant protein-1 (MCP-1) in the serum were measured by Enzyme Linked Immunosorbent Assay (ELISA). The expression levels of TGF-β, α-smooth muscle actin (α-SMA) and collagen I were examined by western blotting and immunohistochemistry. The protein expression levels and mRNA levels of E-cadherin, N-cadherin, vimentin, janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) in peritoneal tissue were determined by western blotting and qRT-PCR. TGF-β1 stimulated human peritoneal mesothelial cells (HPMCs), and the cells were treated with allicin and the JAK2/STAT3 pathway activator colivelin alone or in combination. A cell counting kit-8 (CCK-8) assay was used to measure cell viability. The role of JAK2/STAT3 in the effects of allicin was confirmed via in vitro mechanistic research by western blotting, wound healing assays and Transwell assays. Allicin relieves the inflammatory response by downregulating the levels of IL-1β, IL-6, MCP-1 and TNF-α. Furthermore, allicin decreased the expression of TGF-β, α-SMA and collagen I. Allicin also alleviated epithelial-to-mesenchymal transition (EMT), as specifically manifested by increased E-cadherin and reduced N-cadherin and vimentin. Further studies revealed that allicin reduced the protein levels of JAK2, STAT3, p-JAK2, and p-STAT3. The results of the cellular experiments verified the above results. The ability of allicin to inhibit fibrosis and the EMT process was significantly attenuated after HPMCs were treated with colivelin. Taken together, these findings suggest that allicin inhibits inflammation and EMT, thereby improving PF, and this protective effect may be achieved by inhibiting the JAK2/STAT3 signaling pathway.

A natural products solution to diabetic nephropathy therapy

Diabetic nephropathy is one of the most common complications in diabetes. It has been shown to be the leading cause of end-stage renal disease. However, due to their complex pathological mechanisms, effective therapeutic drugs other than angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), which have been used for 20 years, have not been developed so far. Recent studies have shown that diabetic nephropathy is characterized by multiple signalling pathways and multiple targets, including inflammation, apoptosis, pyroptosis, autophagy, oxidative stress, endoplasmic reticulum stress and their interactions. It definitely exacerbates the difficulty of therapy, but at the same time it also brings out the chance for natural products treatment. In the most recent two decades, a large number of natural products have displayed their potential in preclinical studies and a few compounds are under invetigation in clinical trials. Hence, many compounds targeting these singals have been emerged as a comprehensive blueprint for treating strategy of diabetic nephropathy. This review focuses on the cellular and molecular mechanisms of natural prouducts that alleviate this condition, including preclinical studies and clinical trials, which will provide new insights into the treatment of diabetic nephropathy and suggest novel ideas for new drug development.

Garlic (Allium sativum L.) in diabetes and its complications: Recent advances in mechanisms of action

Diabetes mellitus (DM) is a metabolic disease characterized by chronic hyperglycemia and impaired islet secretion that places a heavy burden on the global health care system due to its high incidence rate, long disease course and many complications. Fortunately, garlic (Allium sativum L.), a well-known medicinal plant and functional food without the toxicity and side effects of conventional drugs, has shown positive effects in the treatment of diabetes and its complications. With interdisciplinary development and in-depth exploration, we offer a clear and comprehensive summary of the research from the past ten years, focusing on the mechanisms and development processes of garlic in the treatment of diabetes and its complications, aiming to provide a new perspective for the treatment of diabetes and promote the efficient development of this field.

Human umbilical cord mesenchymal stem cell-derived exosomal miR-335-5p attenuates the inflammation and tubular epithelial-myofibroblast transdifferentiation of renal tubular epithelial cells by reducing ADAM19 protein levels

BACKGROUND

Renal tubular epithelial-myofibroblast transdifferentiation (EMT) plays a key role in the regulation of renal fibrosis. Exosomes derived from human umbilical cord mesenchymal stem cells (hucMSCs) play a crucial role in alleviating renal fibrosis and injury. Additionally, hucMSC-derived exosomes contain numerous microRNAs (miRNAs). However, it is unclear whether mesenchymal stem cells can regulate the transforming growth factor (TGF)-β1-induced EMT of human renal tubular epithelial cells (RTECs) through exosomal miRNAs.

METHOD

HK-2, a human RTEC line, was co-treated with TGF-β1 and hucMSC-derived exosomes. Additionally, TGF-β1-treated HK-2 cells were transfected with a miR-335-5p mimic and disintegrin and metalloproteinase domain-containing protein 19 (ADAM19)-overexpression plasmid. miR-335-5p expression and ADAM19 protein and inflammation levels were measured via quantitative reverse transcription polymerase chain reaction, western blotting, and enzyme-linked immunosorbent assays, respectively.

RESULTS

TGF-β1 treatment changed the shape of HK-2 cells from a cobblestone morphology to a long spindle shape, accompanied by an increase in interleukin (IL)-6, tumor necrosis factor-α, IL-1β, collagen I, collagen III, α-smooth muscle actin, vimentin, and N-cadherin protein levels, whereas E-cadherin protein levels were reduced in these HK-2 cells, suggesting that TGF-β1 treatment induced the inflammation and EMT of HK-2 cells. HucMSC-exosomes improved the inflammation and EMT phenotype of TGF-β1-induced HK-2 cells by transferring miR-335-5p. miR-335-5p was found to bind the ADAM19 3'-untranslated region to reduce ADAM19 protein levels. Additionally, miR-335-5p improved the inflammation and EMT phenotype of HK-2 cells by reducing ADAM19 protein levels with TGF-β1 induction.

CONCLUSIONS

HucMSC-derived exosomal miR-335-5p attenuates the inflammation and EMT of HK-2 cells by reducing ADAM19 protein levels upon TGF-β1 induction. This study provides a potential therapeutic strategy and identifies targets for clinically treating renal fibrosis.

Hyperosmotic stress induces epithelial-mesenchymal transition through rearrangements of focal adhesions in tubular epithelial cells

Epithelial-mesenchymal transition (EMT) of tubular epithelial cells is a hallmark of renal tubulointerstitial fibrosis and is associated with chronic renal injury as well as acute renal injury. As one of the incidences and risk factors for acute renal injury, increasing the osmolality in the proximal tubular fluid by administration of intravenous mannitol has been reported, but the detailed mechanisms remain unclear. Hyperosmotic conditions caused by mannitol in the tubular tissue may generate not only osmotic but also mechanical stresses, which are known to be able to induce EMT in epithelial cells, thereby contributing to renal injury. Herein, we investigate the effect of hyperosmolarity on EMT in tubular epithelial cells. Normal rat kidney (NRK)-52E cells were exposed to mannitol-induced hyperosmotic stress. Consequently, the hyperosmotic stress led to a reduced expression of the epithelial marker E-cadherin and an enhanced expression of the mesenchymal marker, α-smooth muscle actin (α-SMA), which indicates an initiation of EMT in NKR-52E cells. The hyperosmotic condition also induced time-dependent disassembly and rearrangements of focal adhesions (FAs) concomitant with changes in actin cytoskeleton. Moreover, prevention of FAs rearrangements by cotreatment with Y-27632, a Rho-associated protein kinase inhibitor, could abolish the effects of hyperosmotic mannitol treatment, thus attenuating the expression of α-SMA to the level in nontreated cells. These results suggest that hyperosmotic stress may induce EMT through FAs rearrangement in proximal tubular epithelial cells.

Effects of Allicin on Pathophysiological Mechanisms during the Progression of Nephropathy Associated to Diabetes

This study aimed to assess the impact of allicin on the course of diabetic nephropathy. Study groups included control, diabetes, and diabetes-treated rats. Allicin treatment (16 mg/kg day/p.o.) started after 1 month of diabetes onset and was administered for 30 days. In the diabetes group, the systolic blood pressure (SBP) increased, also, the oxidative stress and hypoxia in the kidney cortex were evidenced by alterations in the total antioxidant capacity as well as the expression of nuclear factor (erythroid-derived 2)-like 2/Kelch ECH associating protein 1 (Nrf2/Keap1), hypoxia-inducible factor 1-alpha (HIF-1α), vascular endothelial growth factor (VEGF), erythropoietin (Epo) and its receptor (Epo-R). Moreover, diabetes increased nephrin, and kidney injury molecule-1 (KIM-1) expression that correlated with mesangial matrix, the fibrosis index and with the expression of connective tissue growth factor (CTGF), transforming growth factor-β1 (TGF-β1), and α-smooth muscle actin (α-SMA). The insulin levels and glucose transporter protein type-4 (GLUT4) expression were decreased; otherwise, insulin receptor substrates 1 and 2 (IRS-1 and IRS-2) expression was increased. Allicin increased Nrf2 expression and decreased SBP, Keap1, HIF-1α, and VEGF expression. Concurrently, nephrin, KIM-1, the mesangial matrix, fibrosis index, and the fibrotic proteins were decreased. Additionally, allicin decreased hyperglycemia, improved insulin levels, and prevented changes in (GLUT4) and IRSs expression induced by diabetes. In conclusion, our results demonstrate that allicin has the potential to help in the treatment of diabetic nephropathy. The cellular mechanisms underlying its effects mainly rely on the regulation of antioxidant, antifibrotic, and antidiabetic mechanisms, which can contribute towards delay in the progression of renal disease.

Effect of Salinomycin on Expression Pattern of Genes Associated with Apoptosis in Endometrial Cancer Cell Line

Background

Salinomycin is part of a group of ionophore antibiotics characterized by an activity towards tumor cells. To this day, the mechanism through which salinomycin induces their apoptosis is not fully known yet. The goal of this study was to assess the expression pattern of genes and the proteins coded by them connected with the process of programmed cell death in an endometrial cancer cell Ishikawa culture exposed to salinomycin and compared to the control.

Materials and Methods

Analysis of the effect of salinomycin on Ishikawa endometrial cancer cells (ECACC 99040201) included a cytotoxicity MTT test (with a concentration range of 0.1-100 µM), assessment of the induction of apoptosis and necrosis by salinomycin at a concentration of 1 µM as well the assessment of the expression of the genes chosen in the microarray experiment (microarray HG-U 133A_2) and the proteins coded by them connected with apoptosis (RTqPCR, ELISA assay). The statistical significance level for all analyses carried out as part of this study was p<0.05.

Results

It was observed that salinomycin causes the death of about 50% of cells treated by it (50.74±0.80% of all cells) at a concentration of 1µM. The decrease in the number of living cells was determined directly after treatment of the cells with the drug (time 0). The average percent of late apoptotic cells was 1.65±0.24% and 0.57±0.01% for necrotic cells throughout the entire observation period.

Discussion

Microarray analysis indicated the following number of mRNA differentiating the culture depending on the time of incubation with the drug: H_12 vs C = 114 mRNA, H_8 vs C = 84 mRNA, H_48 vs. C = 27 mRNA, whereas 5 mRNAs were expressed differently at all times. During the whole incubation period of the cells with the drug, the following dependence of the expression profile of the analyzed transcripts was observed: Bax>p53>FASL>BIRC5>BCL2L.

Conclusion

The analysis carried out indicated that salinomycin, at a concentration of 1 µM, stopped the proliferation of 50% of endometrial cancer cells, mainly by inducing the apoptotic process of the cells. The molecular exponent of the induction of programmed cell death was an observed increase in the transcriptional activity of pro-apoptotic genes: Bax;p53;FASL and a decrease in the expression of anti-apoptotic genes: BCL2L2; BIRC5.

25-OH-PPD inhibits hypertrophy on diabetic cardiomyopathy via the PI3k/Akt/GSK-3β signaling pathway

The present study investigated the inhibitory effects and the associated mechanism of the compound 25-OH-PPD (PPD) on cardiac hypertrophy, fibrosis and inflammation. The signaling pathways associated with diabetic mellitus cardiomyopathy (DMCM) were investigated using a rat model. DMCM Sprague-Dawley rats were induced by injection of streptozotocin. The animals were divided into 5 groups as follows: Normal group (NG group), diabetic group, PPD treatment group, PPD/LY294002 group (inhibitor of PI3K/Akt) and PPD/LiCl group [inhibitor of glycogen synthase kinase (GSK) 3β]. The studies were carried out during the 12 weeks following induction of diabetes and the levels of plasma brain natriuretic peptide (BNP), creatine phosphokinase isoenzyme (CK-MB) were measured. In addition, the volume of myocardial collagen fraction (CVF) was tested. The expression levels of the inflammatory cytokines, including transforming growth factor beta 1 (TGF-β1), connective tissue growth factor (CTGF), cell adhesion molecules α-smooth muscle actin (α-SMA) and vascular adhesion molecule 1 (VCAM-1) and associated signaling proteins (Akt, GSK-3β) were measured by biochemical analyses. The levels of BNP and CK-MB, the volume of CVF, the expression levels of TGF-β1, CTGF, α-SMA and VCAM-1 in the diabetic group were higher compared with those of the normal control group (P<0.05). Conversely, the levels of these molecules were significantly decreased in the PPD treatment groups (P<0.05). The aforementioned effects were partially eliminated in the PPD/LY294002 and PPD/LiCl groups. In addition, PPD treatment significantly increased the expression levels of p-Akt and decreased the levels of phosphorylated GSK-3β compared with those of the DMCM group (P<0.05). The data demonstrated that the protective effects of 25-OH-PPD against DMCM may be attributed to the PI3k/Akt/GSK-3β signaling pathway, via the suppression of the α-SMA/VCAM axis and the downregulation of TGF-β1 and CTGF expression.

The effect of repeated passaging on the susceptibility of human proximal tubular HK-2 cells to toxic compounds

The human proximal tubular HK-2 cell line is an immortalized cell line commonly used for studying proximal tubular toxicity. Even as their use is presently increasing, there unfortunately are no studies focused on functional changes in HK-2 cells associated with passaging. The aim of the present study, therefore, was to evaluate the functional stability of HK-2 cells during 13 weeks of continuous passaging after 6 and 24 h of treatment with model nephrotoxic compounds (i.e., acetaminophen, cisplatin, CdCl(2)). Short tandem repeat profile, the doubling time, cell diameter, glutathione concentration, and intracellular dehydrogenase activity were measured in HK-2 cells at each tested passage. The results showed that HK-2 cells exhibit stable morphology, cell size, and cell renewal during passaging. Mean doubling time was determined to be 54 h. On the other hand, we observed a significant effect of passaging on the susceptibility of HK-2 cells to toxic compounds. The largest difference in results was found in both cadmium and cisplatin treated cells across passages. We conclude that the outcomes of scientific studies on HK-2 cells can be affected by the number of passages even after medium-term cultivation and passaging for 13 weeks.

Flavanomarein inhibits high glucose-stimulated epithelial-mesenchymal transition in HK-2 cells via targeting spleen tyrosine kinase

Flavanomarein (FM) is a major natural compound of Coreopsis tinctoria Nutt with protective effects against diabetic nephropathy (DN). In this study, we investigated the effects of FM on epithelial-mesenchymal transition (EMT) in high glucose (HG)-stimulated human proximal tubular epithelial cells (HK-2) and the underlying mechanisms, including both direct targets and downstream signal-related proteins. The influence of FM on EMT marker proteins was evaluated via western blot. Potential target proteins of FM were searched using Discovery Studio 2017 R2. Gene Ontology (GO) analysis was conducted to enrich the proteins within the protein-protein interaction (PPI) network for biological processes. Specific binding of FM to target proteins was examined via molecular dynamics and surface plasmon resonance analyses (SPR). FM promoted the proliferation of HK-2 cells stimulated with HG and inhibited EMT through the Syk/TGF-β1/Smad signaling pathway. Spleen tyrosine kinase (Syk) was predicted to be the most likely directly interacting protein with FM. Combined therapy with a Syk inhibitor and FM presents significant potential as an effective novel therapeutic strategy for DN.

Allicin suppresses the migration and invasion in cervical cancer cells mainly by inhibiting NRF2

Emerging evidence has demonstrated the antitumor activity of allicin in various tumors. However, little study has been carried out on the functional role of allicin in cervical cancer. Our data showed that allicin suppressed cervical cancer cell viability in a time- and dose-dependent manner. Allicin treatment could reverse H2O2-induced reactive oxygen species accumulation. Meanwhile, levels of glutathione and superoxide dismutase were increased, but malondialdehyde was decreased after allicin incubation for 48 h. Furthermore, TUNEL staining showed that H2O2 treatment induced cell apoptosis, but allicin treatment could decrease cell apoptosis. Western blot assay showed that allicin could suppress the expression of nuclear factor erythroid 2-related factor 2 (NRF2) and heme oxygenase 1. We also showed that NRF2 prompted SiHa cell proliferation and reduced SiHa cell apoptosis. More importantly, allicin-inactivated phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) signaling could be partially reversed by overexpressing of NRF2. We also evaluated cell apoptosis in SiHa cells transfected with plasmid NRF2. Our data showed that allicin-induced cell apoptosis (43.5±3.8%) could largely be abolished by upregulation of NRF2 (12.3±2.08%). In summary, our data showed allicin was effective in suppressing the malignant phenotype of cervical cancer cells mainly by inhibiting the expression of NRF2, showing the potential clinical benefits of allicin in cervical cancer patients.

Immunomodulatory Effects of the Nutraceutical Garlic Derivative Allicin in the Progression of Diabetic Nephropathy

Diabetic nephropathy (DN) is presently the primary cause of chronic kidney disease and end-stage renal disease (ESRD). It has been suggested that inflammation and oxidative stress, in addition to or in concert with the metabolic changes, plays an important role in the maintenance and progression of the disease. Therefore, attenuating or blocking these mechanisms may be a therapeutic target to delay the progression of the disease. Diallyl thiosulfinate (allicin), a compound derived from garlic, inhibits free radical formation, increases glutathione synthesis and decreases the levels of proinflammatory molecules in vitro. This research aimed to assess the effect of allicin on oxidative stress and inflammation-induced diabetes. Animals were divided into control and diabetes (streptozotocin 50 mg/kg i.p.), and maintained for 30 days. After 30 days, the group of diabetic animals was subdivided into diabetes and allicin-treated diabetes (16 mg/kg/day oral gavage). The three experimental groups were maintained for another month. We analyzed the status of renal function, oxidative stress and proinflammatory cytokines. The untreated diabetic group showed hyperglycemia and increased diuresis, creatinine clearance, proteinuria, glycosuria and urinary excretion of N-acetyl-β-d-glucosaminidase (NAG), as well as increased oxidative stress and the expression of interleukin 1β (IL-1β), IL-6, nuclear factor kappa beta (NFκβ) and transforming growth factor-β1 (TGF-β1) in plasma and kidney. In contrast, the inhibitor of NFκβ (Iκβ) is decreased in the cortex. It has been demonstrated that the allicin treatment decreases hyperglycemia, polyuria, and NAG excretion. The oxidative stress and proinflammatory cytokines were also reduced by the allicin treatment. In conclusion, allicin delays the progression of diabetic nephropathy through antioxidant and anti-inflammatory mechanisms.

Non-genetic mechanisms of diabetic nephropathy

Diabetic nephropathy (DN) is one of the most common microvascular complications in diabetes mellitus patients and is characterized by thickened glomerular basement membrane, increased extracellular matrix formation, and podocyte loss. These phenomena lead to proteinuria and altered glomerular filtration rate, that is, the rate initially increases but progressively decreases. DN has become the leading cause of end-stage renal disease. Its prevalence shows a rapid growth trend and causes heavy social and economic burden in many countries. However, this disease is multifactorial, and its mechanism is poorly understood due to the complex pathogenesis of DN. In this review, we highlight the new molecular insights about the pathogenesis of DN from the aspects of immune inflammation response, epithelial-mesenchymal transition, apoptosis and mitochondrial damage, epigenetics, and podocyte-endothelial communication. This work offers groundwork for understanding the initiation and progression of DN, as well as provides ideas for developing new prevention and treatment measures.