Cinnamaldehyde and nitric oxide attenuate advanced glycation end products-induced the Jak/STAT signaling in human renal tubular cells

Cinnamon and cognitive function: a systematic review of preclinical and clinical studies

Cinnamon is the inner bark of trees named Cinnamomum. Studies have shown that cinnamon and its bioactive compounds can influence brain function and affect behavioral characteristics. This study aimed to systematically review studies about the relationship between cinnamon and its key components in memory and learning. Two thousand six hundred five studies were collected from different databases (PubMed, Scopus, Google Scholar, and Web of Science) in September 2021 and went under investigation for eligibility. As a result, 40 studies met our criteria and were included in this systematic review. Among the included studies, 33 were In vivo studies, five were In vitro, and two clinical studies were also accomplished. The main outcome of most studies (n = 40) proved that cinnamon significantly improves cognitive function (memory and learning). In vivo studies showed that using cinnamon or its components, such as eugenol, cinnamaldehyde, and cinnamic acid, could positively alter cognitive function. In vitro studies also showed that adding cinnamon or cinnamaldehyde to a cell medium can reduce tau aggregation, Amyloid β and increase cell viability. For clinical studies, one study showed positive effects, and another reported no changes in cognitive function. Most studies reported that cinnamon might be useful for preventing and reducing cognitive function impairment. It can be used as an adjuvant in the treatment of related diseases. However, more studies need to be done on this subject.

Role of advanced glycation end products in diabetic vascular injury: molecular mechanisms and therapeutic perspectives

BACKGROUND

In diabetic metabolic disorders, advanced glycation end products (AGEs) contribute significantly to the development of cardiovascular diseases (CVD).

AIMS

This comprehensive review aims to elucidate the molecular mechanisms underlying AGE-mediated vascular injury.

CONCLUSIONS

We discuss the formation and accumulation of AGEs, their interactions with cellular receptors, and the subsequent activation of signaling pathways leading to oxidative stress, inflammation, endothelial dysfunction, smooth muscle cell proliferation, extracellular matrix remodeling, and impaired angiogenesis. Moreover, we explore potential therapeutic strategies targeting AGEs and related pathways for CVD prevention and treatment in diabetic metabolic disorders. Finally, we address current challenges and future directions in the field, emphasizing the importance of understanding the molecular links between AGEs and vascular injury to improve patient outcomes.

JAK2/STAT3 Signaling Pathway and Klotho Gene in Cadmium-induced Neurotoxicity In Vitro and In Vivo

Cadmium (Cd), a common heavy metal in the environment, is associated with cognitive impairment. In the present study, we carried out a preliminary inquiry to explore whether Cd causes neurotoxicity by regulating the JAK2/STAT3 signaling pathway and affecting the expression of klotho genes in vivo and in vitro, providing clues for the mechanism of Cd-induced cognitive dysfunction. The rat samples were injected with Cd chloride solution for 14 weeks, and the memory function of the rats was detected. Different concentrations of Cd and JAK2/STAT3 signaling pathway inhibitors were used to treat PC12 cells and thus detect the apoptosis rate. The protein expression levels of JAK2, p-JAK2, STAT3, p-STAT3, and klotho in rat and PC12 cell were detected by ELISA and Western blot, respectively. With the increase in exposure dose, the memory function of rats was severely impaired. The expression of p-JAK2 and p-STAT3 proteins was significantly up-regulated, whereas that of klotho was significantly down-regulated both in vivo and in vitro (p < 0.05). In comparison with the high-dose Cd exposure group, after adding tyrphostin AG490 (AG490), the apoptosis rate of PC12 cells increased, whereas the phosphorylation levels of JAK2 and STAT3 in the cells decreased significantly (p < 0.05). Cd exposure may cause neurotoxicity by regulating the JAK2/STAT3 signaling pathway and down-regulating klotho protein expression, leading to cognitive dysfunction.

STAT-3 signaling role in an experimental model of nephropathy induced by doxorubicin

The focal segmental glomerulosclerosis (FSGS) is one of the most frequent glomerulopathy in the world, being considered a significative public health problem worldwide. The disease is characterized by glomerular loss mainly due to inflammation process and collagen fibers deposition. STAT-3 is a transcription factor associated with cell differentiation, migration and proliferation and in renal cells it has been related with fibrosis, acting on the progression of the lesion. Considering this perspective, the present study evaluated the involvement of STAT-3 molecule in an experimental model of FSGS induced by Doxorubicin (DOX). DOX mimics primary FSGS by causing both glomerular and tubular lesions and the inhibition of the STAT3 pathway leads to a decrease in fibrosis and attenuation of kidney damage. We described here a novel FSGS experimental model in a strain of genetically heterogeneous mice which resembles the reality of FSGS patients. DOX-injected mice presented elevated indices of albuminuria and glycosuria, that were significantly reduced in animals treated with a STAT-3 inhibitor (STATTIC), in addition with a decrease of some inflammatory molecules. Moreover, we detected that SOCS-3 (a regulator of STAT family) was up-regulated only in STATTIC-treated mice. Finally, histopathological analyzes showed that DOX-treated group had a significant increase in a tubulointerstitial fibrosis and tubular necrosis, which were not identified in both control and STATTIC groups. Thus, our results indicate that STAT-3 pathway possess an important role in experimental FSGS induced by DOX and may be an important molecule to be further investigated.

Mechanism of Cornus Officinalis in Treating Diabetic Kidney Disease Based on Network Pharmacology

Diabetic kidney disease (DKD), one of the most important diabetic complications, is a great clinical challenge. It still lacks proper therapeutic strategies without side effects due to the complex pathological mechanisms. Cornus officinalis (CO) is a common traditional Chinese medicine, which has been used in the treatment of DKD and takes beneficial effects in therapy. However, the mechanism of CO in treating DKD is not clear yet. In this study, network pharmacology was applied to illustrate the potential mechanism of CO and the interaction between targets of CO and targets of disease. First, the active ingredients of CO and related targets were screened from the online database. Second, the intersection network between CO and disease was constructed, and protein–protein interaction analysis was done. Third, GO and KEGG analysis were employed to figure out the key targets of CO. Finally, molecular docking was carried out in the software SYBYL to verify the effectiveness of the ingredients and targets selected. According to GO and KEGG analysis, drug metabolism-cytochrome P450, sphingolipid signaling pathway, HIF-1 signaling pathway, TGF-beta signaling pathway, cGMP-PKG signaling pathway, estrogen signaling pathway, and TNF signaling pathway were most closely related to the pathogenesis of DKD. Moreover, NOS3, TNF, ROCK1, PPARG, KDR, and HIF1A were identified as key targets in regulating the occurrence and development of the disease. This study provides evidence to elucidate the mechanism of CO comprehensively and systematically and lays the foundation for further research on CO.

AGE/RAGE in diabetic kidney disease and ageing kidney

Diabetic kidney disease (DKD) is the primary cause of chronic kidney disease that inevitably progress to end-stage kidney disease. Intervention strategies such as blood glucose control is effective for preventing DKD, but many patients with DKD still reach end-stage kidney disease. Although comprehensive mechanisms shed light on the progression of DKD, the most compelling evidence has highlighted that hyperglycemia-related advanced glycation end products (AGEs) formation plays a central role in the pathogenesis of DKD. Pathologically, accumulation of AGEs-mediated receptor for AGEs (RAGE) triggers oxidative stress and inflammation, which is the major deleterious effect of AGEs in host and intestinal microenvironment of diabetic and ageing conditions. The activation of AGEs-mediated RAGE could evoke nicotinamide adenine dinucleotide phosphate oxidase-induced reactive oxygen and nitrogen species production and subsequently give rise to oxidative stress in DKD and ageing kidney. Therefore, targeting RAGE with its ligands mediated oxidative stress and chronic inflammation is considered as an additional intervention strategy for DKD and ageing kidney. In this review, we summarize AGEs/RAGE-mediated oxidative stress and inflammation signaling pathways in DKD and ageing kidney, discussing opportunities and challenges of targeting at AGEs/RAGE-induced oxidative stress that could hold the promising potential approach for improving DKD and ageing kidney.

Dietary advanced glycation end-products elicit toxicological effects by disrupting gut microbiome and immune homeostasis

The aging immune system is characterized by a low-grade chronic systemic inflammatory state ("inflammaging") marked by elevated serum levels of inflammatory molecules such as interleukin (IL)-6 and C-reactive protein (CRP). These inflammatory markers were also reported to be strong predictors for the development/severity of Type 2 diabetes, obesity, and COVID-19. The levels of these markers have been positively associated with those of advanced glycation end-products (AGEs) generated via non-enzymatic glycation and oxidation of proteins and lipids during normal aging and metabolism. Based on the above observations, it is clinically important to elucidate how dietary AGEs modulate inflammation and might thus increase the risk for aging-exacerbated diseases. The present narrative review discusses the potential pro-inflammatory properties of dietary AGEs with a focus on the inflammatory mediators CRP, IL-6 and ferritin, and their relations to aging in general and Type 2 diabetes in particular. In addition, underlying mechanisms - including those related to gut microbiota and the receptors for AGEs, and the roles AGEs might play in affecting physiologies of the healthy elderly, obese individuals, and diabetics are discussed in regard to any greater susceptibility to COVID-19.

Hirudo Lyophilized Powder Ameliorates Renal Injury in Diabetic Rats by Suppressing Oxidative Stress and Inflammation

As diabetic nephropathy (DN) is one of the most common and destructive microvascular complications of diabetes mellitus, the goal of this study, therefore, was to investigate the renal protective effect and latent mechanisms of Hirudo lyophilized powder on diabetic rats. In this study, all rats were randomly assigned into the control group and diabetic group. The rats of diabetic group were injected with low-dose STZ (35 mg/kg) intraperitoneal plus high-fat diet to induce diabetes. Then, the successful diabetic model rats were weighed and randomly assigned into four groups: (1) diabetic model group (DM group); (2) Hirudo lyophilized powder 0.3 g/kg treatment group (SL group); (3) Hirudo lyophilized powder 0.6 g/kg treatment group (SM group); (4) Hirudo lyophilized powder 1.2 g/kg treatment group (SH group). Their fasting blood glucoses (FBG) were measured every 4 weeks. After treatment with Hirudo lyophilized powder at a corresponding dose once a day for 16 weeks, their metabolic and biochemical as well as oxidative stress parameters were tested, and the kidney weight (KW)/body weight (BW) was calculated. The renal tissues were used for histological, mRNA, and protein expression analysis. The results showed that Hirudo lyophilized powder could protect against the structural damages and functional changes of diabetic renal tissue by inhibiting oxidative stress, inflammation, and fibrosis. Furthermore, it was found in the further research that inhibiting the NOX4 expression and JAK2/STAT1/STAT3 pathway activation might be the underlying mechanisms. Collectively, Hirudo lyophilized powder might be a promising therapeutic agent for the treatment of DN.

Cinnamaldehyde and hesperetin attenuate TNBS-induced ulcerative colitis in rats through modulation of the JAk2/STAT3/SOCS3 pathway

Ulcerative colitis is an autoimmune inflammatory disorder with a negative impact on the life quality of patients. Cinnamaldehyde and hesperetin were chosen due to their antioxidants and anti-inflammatory effects. This study explored the protective effects of cinnamaldehyde (40 and 90 mg/kg, po) and hesperetin (50 and 100 mg/kg, po) on 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced ulcerative colitis in rats. Cinnamaldehyde and hesperetin significantly improved macroscopic and histopathological examinations with a significant reduction in myeloperoxidase and intracellular adhesion molecule-1 expression. They significantly reduced colon oxidative stress by a significant elevation in both reduced glutathione content and superoxide dismutase activity with a significant reduction of NO content. Furthermore, cinnamaldehyde and hesperetin alleviated the inflammatory injury by a significant reduction in interleukin-6 along with suppression of nuclear factor-κB, receptor for advanced glycation end products, and tumor necrosis factor-α expression. Moreover, cinnamaldehyde and hesperetin significantly decreased p-JAK2 and p-STAT3 while significantly increased suppressors of cytokine signaling 3 (SOCS3) protein expression. In conclusion, cinnamaldehyde and hesperetin counteracted TNBS-induced ulcerative colitis through antioxidant, anti-inflammatory properties as well as modulation of the JAk2/STAT3/SOCS3 pathway.

Jingshu Keli for treating cervical spondylotic radiculopathy: The first multicenter, randomized, controlled clinical trial

Background

Jingshu Keli (or Jingshu granules), a traditional Chinese medicine, are widely used for treating cervical spondylotic radiculopathy in China; however, no randomized, double-blind, controlled study has verified their effectiveness.

Purpose

To evaluate the efficacy and safety of Jingshu Keli for the treatment of cervical spondylotic radiculopathy in a randomized controlled trial.

Design

From August 2015 to July 2017, a multicenter, randomized, double-blind, placebo-controlled trial was conducted at 13 large- and medium-sized hospitals in China.

Patient sample

A total of 360 and 120 patients were initially enrolled in the Jingshu and control groups, respectively; 386 patients completed the study, with 299 in the Jingshu group and 87 in the control group.

Outcome measures

The main index for evaluating the curative effect was the pain score on a visual analogue scale (VAS; 0–100 points).

Methods

All patients were administered a bag of Jingshu Keli or placebo 3 times a day for 4 weeks, and were interviewed at the second and fourth weeks. The decrease in pain scores and rate of change in pain scores after treatment were calculated, related laboratory indices were reviewed, and adverse reactions were recorded.

Results

In the Per Protocol Set (PPS) analysis, the baseline pain VAS scores in the control and Jingshu groups were 49.31 ​± ​6.97 and 50.06 ​± ​7.33, respectively, with no significant difference between the groups (P ​> ​0.05). While there were no differences at 2 weeks between groups, at four weeks the pain VAS scores in the control and Jingshu groups decreased by 12.86 ​± ​13.45 and 22.72 ​± ​15.08, respectively relative to the values at baseline, with significant group differences (P ​< ​0.0001). While there were similar significant differences between the groups (P ​< ​0.0001) in the Full Analysis Set (FAS) analyses neither group achieved the minimal clinically important difference at any time point.

Conclusions

Jingshu Keli are effective for the treatment of cervical spondylotic radiculopathy.

Translational potential statement

This is the first prospective, multicenter, randomized, double-blind, placebo-controlled clinical trial that confirmed the clinical efficacy and safety of Jingshu Keli for treating cervical spondylotic radiculopathy, which can provide evidence for clinical treatment.

Aliskiren, tadalafil, and cinnamaldehyde alleviate joint destruction biomarkers; MMP-3 and RANKL; in complete Freund's adjuvant arthritis model: Downregulation of IL-6/JAK2/STAT3 signaling pathway

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease, which is accompanied by progressive joint damage and disability. The intolerability of conventional antirheumatic drugs by some patients necessitates the search for effective antirheumatic agents having better tolerability. In the current work, we aimed to investigate the efficacy of cinnamaldehyde, tadalafil, and aliskiren as potential antirheumatic candidates and to explore their modulatory effects on joint destruction, inflammatory response, and intracellular signaling. Arthritis was induced in female Wistar rats by complete Freund's adjuvant (CFA) 0.4 ml s.c. on days 1, 4, and 7. Treated groups received their respective drugs, starting from day 13, daily for 3 weeks. Methotrexate and prednisolone were the standard antirheumatic drugs, while cinnamaldehyde, tadalafil, and aliskiren were the test agents. Treatment with cinnamaldehyde, tadalafil, or aliskiren reduced serum levels of rheumatoid factor, and pro-inflammatory cytokines; tumor necrosis factor-alpha and interleukin-6 (IL-6), along with elevated level of IL-10 which is an anti-inflammatory cytokine. Besides, cartilage and bone destruction biomarkers; matrix metalloproteinase-3 (MMP-3) and receptor activator of nuclear factor-kappa B ligand (RANKL); were significantly reduced after treatment with the test agents, which was further confirmed by histopathological investigation. The elevated protein expressions of phosphorylated-Janus kinase 2 (p-JAK2), phosphorylated-signal transducer and activator of transcription 3 (p-STAT3), and inducible nitric oxide synthase (iNOS) in articular tissue were markedly attenuated after treatment with cinnamaldehyde, tadalafil, or aliskiren, while that of endothelial nitric oxide synthase (eNOS) was greatly enhanced. In addition, oxidative stress and inflammatory markers such as malondialdehyde, nitric oxide, and myeloperoxidase were reduced in joint tissue after treatment with the test agents, while glutathione content was elevated. Furthermore, the renin inhibitor aliskiren produced effects close to those of the normal and methotrexate, the gold standard antirheumatic drug, in most of the measured parameters.

Collectively, these findings led to the assumption that the downregulation of IL-6/JAK2/STAT3 signaling by cinnamaldehyde, tadalafil, and aliskiren could alleviate joint destruction by MMP-3 and RANKL, reduce iNOS, and enhance eNOS expressions. Moreover, aliskiren could be a promising therapeutic agent for RA, because of its ability to normalize most of the measured parameters after CFA-induced arthritis.

The modulatory effects of cinnamaldehyde on uric acid level and IL-6/JAK1/STAT3 signaling as a promising therapeutic strategy against benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is a widespread disorder in elderly men. Cinnamaldehyde, which is a major constituent in the essential oil of cinnamon, has been previously reported to reduce xanthine oxidase activity, in addition to its anti-inflammatory, anti-oxidant, and anti-proliferative activities. Our study was designed to investigate the potential modulatory effects of cinnamaldehyde on testosterone model of BPH in rats through reduction of uric acid level, and suppression of IL-6/JAK1/STAT3 signaling pathway. Cinnamaldehyde (40 and 75 mg/kg) was orally administered to male Wistar rats for 3 weeks, and concurrently with testosterone (3 mg/kg, s.c.) from the second week. Cinnamaldehyde ameliorated the elevation in prostatic weight and index compared to rats treated with testosterone only, that was also confirmed by alleviation of histopathological changes in prostate architecture. The protective mechanisms of cinnamaldehyde were elucidated through inhibition of xanthine oxidase activity and reduced uric acid level. That was accompanied by reduction of the pro-inflammatory cytokines; interleukin-6 (IL-6), IL-1β, tumor necrosis factor-alpha (TNF-α), and the nuclear translocation of the transcription factor NF-κB p65, that could be attributed also to the enhanced anti-oxidant defense by cinnamaldehyde. The protein expression of JAK1, which is IL-6 receptor linked protein, was reduced with subsequently reduced activation of STAT3 protein. That eventually suppressed the formation of the proliferation protein cyclin D1, while elevated Bax/Bcl2 ratio. It can be concluded that reducing uric acid level through xanthine oxidase inhibition and suppression of the inflammatory signaling cascade; IL-6/JAK1/STAT3; by cinnamaldehyde could be a novel and promising therapeutic approach against BPH.

STAT signaling in polycystic kidney disease

The most common form of polycystic kidney disease (PKD) in humans is caused by mutations in the PKD1 gene coding for polycystin1 (PC1). Among the many identified or proposed functions of PC1 is its ability to regulate the activity of transcription factors of the STAT family. Most STAT proteins that have been investigated were found to be aberrantly activated in kidneys in PKD, and some have been shown to be drivers of disease progression. In this review, we focus on the role of signal transducer and activator of transcription (STAT) signaling pathways in various renal cell types in healthy kidneys as compared to polycystic kidneys, on the mechanisms of STAT regulation by PC1 and other factors, and on the possibility to target STAT signaling for PKD therapy.

Cinnamaldehyde Ameliorates Vascular Dysfunction in Diabetic Mice by Activating Nrf2

BACKGROUND

Oxidative stress is known to be associated with the development of diabetes. Cinnamaldehyde (CA) is a spice compound in cinnamon that enhances the antioxidant defense against reactive oxygen species (ROS) by activating nuclear factor erythroid-related factor 2 (Nrf2), which has been shown to have a cardioprotection effect. However, the relationship between CA and Nrf2 in diabetic vascular complications remains unclear.

METHODS

Leptin receptor-deficient (db/db) mice were fed normal chow or diet containing 0.02% CA for 12 weeks. The vascular tone, blood pressure, superoxide level, nitric oxide (NO) production, renal morphology, and function were measured in each group.

RESULTS

CA remarkably inhibited ROS generation, preserved NO production, increased phosphorylated endothelial nitric oxide synthase (p-eNOS), attenuated the upregulation of nitrotyrosine, P22 and P47 in aortas of db/db mice, and apparently ameliorated the elevation of type IV collagen, TGF-β1, P22, and P47 in kidney of db/db mice. Feeding with CA improved endothelium-dependent relaxation of aortas and mesenteric arteries, and alleviated the remodeling of mesenteric arteries in db/db mice. Additionally, dietary CA ameliorated glomerular fibrosis and renal dysfunction in diabetic mice. Nrf2 and its targeted genes heme oxygenase-1 (HO-1) and quinone oxidoreductase-1 (NQO-1) were slightly increased in db/db mice and further upregulated by CA. However, these protective effects of CA were reversed in Nrf2 downregulation mice.

CONCLUSIONS

A prolonged diet of CA protects against diabetic vascular dysfunction by inhibiting oxidative stress through activating of Nrf2 signaling pathway in db/db mice.

Beneficial Biological Activities of Cinnamomum osmophloeum and its Potential Use in the Alleviation of Oral Mucositis: A Systematic Review

The aim of this review was to provide an updated overview of studies on the medical-biological activities of Cinnamomum osmophloeum (C. osmophloeum) in vitro and in vivo and the potential therapeutic use of natural agents prepared from this plant for the alleviation of oral mucositis (OM). Reported articles were collected using web search engine tools. The systematic review was organized according to the preferred reporting items for reviews and meta-analyses (PRISMA) statement. Additional sources were identified through cross-referencing to identify the potential use of C. osmophloeum in the alleviation of OM. The results disclosed that C. osmophloeum is comprised of bioactive ingredients that could act diversely as a reagent in anti-inflammation, antibacterial, antioxidant, anti-hyperglycemic, antidyslipidemia, anti-cancer, renal disease therapy and anti-hyperuricemia capacities. Recent studies revealed that the overall effects on anti-inflammation, wound repair, and the antibacterial and antioxidant activities of its constituents would act as a potential remedy for oral mucositis. Up-to-date in vitro and in vivo studies on the medical-biological activities of C. osmophloeum suggested that C. osmophloeum and its constituents could be promising remedies as adjuvants in OM therapy and warrant further investigation.

Involvement of STAT3 Signaling in High Glucose-Induced Epithelial Mesenchymal Transition in Human Peritoneal Mesothelial Cell Line HMrSV5

Background/Aims: Peritoneal fibrosis (PF) is a common complication in patients receiving long-term peritoneal dialysis, which results in damage to peritoneal functions. Epithelial-mesenchymal transition (EMT) is a key step in the early pathogenesis of PF. Increasing evidence has shown that signal transducer and activator of transcription 3 (STAT3) signaling pathway is involved in EMT and tissue fibrosis by interacting with distinct EMT-inducing molecules, including transforming growth factor (TGF)-β and advanced glycation end products (AGEs). This study investigated the involvement of STAT3 in the PF process. Methods: We used high glucose-treated human peritoneal mesothelial cell line HMrSV5 as an in vitro model to expose the peritoneal mesothelial cells to high-glucose dialysate. Expression of EMT markers was detected by qRT-PCR. Accumulation of methylglyoxal (MGO) and AGEs in the culture supernatant were measured by enzyme-linked immunosorbent assay. Phosphorylation of STAT3 was assessed by Western blot. Results: Results showed that high glucose upregulated TGF-β, increased the productions of MGO and AGEs, and induced EMT in HMrSV5 cells. High glucose also activated the STAT3 pathway. STAT3 inhibitor reduced the high glucose-induced EMT, via reducing TGF-β expression and repressing the accumulation of MGO and AGEs. Conclusion: Our results revealed a critical role for STAT3 signaling in high glucose-induced EMT in HMrSV5 cells, and suggested that inhibition of STAT3 might be a treatment for high glucose-induced fibrogenesis in PF.

Jingshu Keli attenuates cervical spinal nerve ligation-induced allodynia in rats through inhibition of spinal microglia and Stat3 activation

BACKGROUND CONTEXT

Cervical radicular pain resulting from mechanical compression of a spinal nerve secondary to spinal degenerative alternations negatively impacts patients' quality of life. Jingshu Keli (JSKL), a traditional Chinese medicine formula with multiple active compounds, has been prescribed for pain management in patients with cervical radiculopathy for decades. Two major components of JSKL, ferulic acid and cinnamaldehyde, were identified to have anti-inflammation effect via inhibiting activation of Stat3.

PURPOSE

To investigate the efficacy of JSKL by investigating its mechanism in attenuating cervical radiculopathy-induced mechanical allodynia via modulation activation of spinal microglia and phosphorylation of signal transducer and activator of transcription 3 (Stat3).

STUDY DESIGN

An in vivo animal experiment.

METHODS

Cervical radiculopathy of rats was established by C7 spinal nerve ligation (SNL) with 6-0 silk suture. The effect of postoperational daily gavage of JSKL on mechanical allodynia of rats was tested on day 3, 7, and 14 after surgery. Furthermore, spinal glial cells activation and phosphorylation of Stat3 (p-Stat3) were tested with immunofluorescence imaging and Western blot.

RESULT

The JSKL significantly inhibited SNL-induced allodynia as well as microglia activation in the spinal cord on day 7 and 14 after surgery. Moreover, expression of p-Stat3 was decreased in rats with SNL and JSKL treatment in comparison with rats with SNL and vehicle treatment.

CONCLUSIONS

The JSKL attenuated SNL-induced mechanical allodynia in rats. This analgesic effect might be explained by the suppression of activations of spinal microglia as well as p-Stat3. Our study provides experimental evidence for JSKL as an alternative approach to manage refractory pain in patients with cervical radiculopathy.

Upregulation of MiR-126 Delays the Senescence of Human Glomerular Mesangial Cells Induced by High Glucose via Telomere-p53-p21-Rb Signaling Pathway

Diabetic kidney disease (DKD) is a microvascular complication of type 2 diabetes. The study of DKD mechanisms is the most important target for the prevention of DKD. Renal senescence is one of the important pathogeneses for DKD, but the mechanism of renal and cellular senescence is unclear. Decreased expression of circulating miR-126 is associated with the development of DKD and may be a promising blood-based biomarker for DKD. This study is to probe the effect and mechanism of miR-126 on the aging of human glomerular mesangial cells (HGMCs) induced by high glucose. HGMCs were cultured with Roswell Park Memorial Institute (RPMI-1640) in vitro. The effect of high glucose on morphology of HGMCs was observed 72 h after intervention. The cell cycle was examined by flow cytometry. The telomere length was measured by Southern blotting. The expression levels of p53, p21 and Rb proteins in p53-p21-Rb signaling pathway and p-stat1, p-stat3 in JAK/STAT signaling pathway were detected by Western blotting respectively. The expression of miR-126 was examined by qRT-PCR. MiR-126 mimics was transfected into HGMCs. The effects of miR-126 mimics transfection on cell morphology, cell cycle, telomere length, p53, p21, Rb, p-stat1 and p-stat3 were observed. The results showed that high glucose not only arrested the cell cycle in G1 phase but also shortened the telomere length. High glucose led to high expression of p53, p21, Rb, p-stat1 and p-stat3 and premature senescence of HGMCs by activating the telomere-p53-p21-Rb and JAK/STAT signaling pathways. Moreover, the miR-126 was decreased in HGMCs induced by high glucose. It was suggested that the transfection of miR-126 mimics could inhibit the telomere-p53-p21-Rb and JAK/STAT signaling pathway activity in vitro and delay the senescence of HGMCs. The results may serve as a new strategy for the treatment of DKD.

Advanced glycation end products induce the apoptosis of and inflammation in mouse podocytes through CXCL9-mediated JAK2/STAT3 pathway activation

Diabetic nephropathy (DN) is a serious and one of the most common microvascular complications of diabetes. There is accumulating evidence to indicate that advanced glycation end products (AGEs), senescent macroprotein derivatives formed at an accelerated rate under conditions of diabetes, play a role in DN. In this study, we found that the serum and urine levels of C-X-C motif chemokine ligand 9 (CXCL9) were significantly elevated in patients with DN compared with healthy controls. Based on an in vitro model of mouse podocyte injury, AGEs decreased the proliferation of podocytes and increased the expression of CXCL9 and C-X-C motif chemokine receptor 3 (CXCR3), and promoted the activation of signal transducer and activator of transcription 3 (STAT3). The knockdown of CXCL9 by the transfection of mouse podoyctes with specific siRNA significantly increased the proliferation and decreased the apoptosis of the podoyctes. Moreover, the levels of inflammatory factors, such as tumor necrosis factor (TNF)-α and interleukin (IL)-6 were also decreased in the podoyctes transfected with siRNA-CXCL9, accompanied by the increased expression of nephrin and podocin, and decreased levels of Bax/Bcl-2 and activated caspase-3. The knockdown of CXCL9 also led to the inactivation of the Janus kinase 2 (JAK2)/STAT3 pathway. Importantly, the use of the JAK2 inhibitor, AG490, and valsartan (angiotensin II receptor antagonist) attenuated the injury induced to mouse podoyctes by AGEs. On the whole, and to the best of our knowledge, this study demonstrates for the first time that AGEs exert pro-apoptotic and pro-inflammatory effects in mouse podoyctes through the CXCL9-mediated activation of the JAK2/STAT3 pathway. Thus, our data provide a potential therapeutic target for DN.

Effect of Cinnamaldehyde on Glucose Metabolism and Vessel Function

Background

Material/Methods

Results

Conclusions

DJC Suppresses Advanced Glycation End Products-Induced JAK-STAT Signaling and ROS in Mesangial Cells

The antidiabetic properties and anti-inflammatory effects of Danzhi Jiangtang Capsules (DJC) have been demonstrated in clinical and laboratory experiments. In this study, we explored whether DJC can ameliorate advanced glycation end products- (AGEs-) mediated cell injury and the precise mechanisms of DJC in treating diabetic nephropathy (DN). Western blot analysis was employed to assess the expressions of iNOS, COX2, and SOCS and the phosphorylation of JAK2, STAT1, and STAT3 in glomerular mesangial cells (GMCs) after treatment with DJC. TNF-α, IL-6, and MCP-1 were determined using double-antibody sandwich ELISA. ROS and NADPH oxidase activity were measured by DCFH-DA assay and lucigenin-enhanced chemiluminescence, respectively. DJC significantly reversed the AGEs-induced expression of COX2 and iNOS. Moreover, DJC inhibited the AGEs-induced JAK2-STAT1/STAT3 activation, resulting in the inhibition of inflammatory cytokines such as IL-6, MCP-1, and TNF-α in a concentration-dependent manner. The ability of DJC to suppress STAT activation was also verified by the observation that DJC significantly increased the SOCS3 protein level. DJC reversed the AGEs-induced accumulation of ROS and NADPH oxidase activity, thus confirming that DJC possesses antioxidant activity. The results suggest that the anti-inflammatory effects of DJC in GMCs may be due to its ability to suppress the JAK2-STAT1/STAT3 cascades and reduce ROS production.

Cinnamaldehyde Ameliorates Cadmium-Inhibited Root Elongation in Tobacco Seedlings via Decreasing Endogenous Hydrogen Sulfide Production

Cinnamaldehyde (CA) is natural plant-derived compound that has been highly appreciated for its medicinal properties. However, little information is known about the regulation of plant intrinsic physiology by CA. To address these gaps, physiological, histochemical, and biochemical approaches were applied to investigate CA-facilitated cadmium (Cd) tolerance in the roots of tobacco (Nicotiana tabacum) seedlings. Treatment with CdCl₂ at 20 μM for 72 h resulted in the significant decrease in root elongation by 40.39% as compared to control. CA alleviated Cd-inhibited root elongation in dose- and time-dependent manners. The addition of CA at 20 μM induced significant increase in root elongation by 42.58% as compared to Cd treatment alone. CA abolished Cd-induced ROS (reactive oxygen species) accumulation, lipid peroxidation, loss of membrane integrity, cell death, and free Cd2+ accumulation in roots. CA blocked the Cd-induced increase in the endogenous H₂S level through the down-regulation of d-cysteine desulfhydrase (DCD) expression. H₂S scavenger hypotaurine (HT) or potent H₂S-biosynthetic inhibitor dl-propargylglicine (PAG) were able mimic the action of CA on the blockade of Cd-induced H₂S accumulation, cell death, and growth inhibition. Enhancement of the endogenous H₂S level with NaHS (H₂S donor) abrogated all the beneficial capabilities of CA, HT, and PAG. Collectively, these results suggest that CA has great potential to confer plant tolerance against Cd stress, which is closely associated with its capability to inhibit Cd-induced H₂S production. This study not only provides evidences for the regulation of plant physiology by CA but also sheds new light on the cross-talk between CA and H₂S in physiological modulations.

Reversal of diabetes-induced behavioral and neurochemical deficits by cinnamaldehyde

BACKGROUND

Chronic hyperglycemia during diabetes is associated with altered cognitive function. Cinnamaldehyde showed to have many pharmacological activities indicating anti-diabetic, cognitive enhancer, antiinflammatory etc. In the present study, we have investigated the effects of cinnamaldehyde (CA) on diabetes-induced cognitive deficits.

METHODS

Diabetes was induced in Sprague Dawley rats using high fat diet followed by streptozotocin (35mg/kg, i.p.). High fat diet feeding was continued for 18 week after STZ administration. CA was administered daily during the last 3 weeks (week 16-18) at a doses of 10, 20 and 40mg/kg (p.o.). Animals were subjected to behavioral tests during 18th week. Neurotransmitter levels (glutamate and GABA), acetylcholine esterase (AChE) activity and inflammatory markers (TNF-α and IL-6) were assessed in the hippocampus and cortex.

RESULTS

Vehicle-treated diabetic rats showed impaired behavior in open field, elevated plus maze and water maze test compared to age-matched control rats. Cinnamaldehyde showed significant reduction in blood glucose levels at dose of 20 and 40mg/kg. Three weeks treatments of cinnamaldehyde showed significant amelioration of behavioral deficits in diabetic rats. Chronic treatment with cinnamaldehyde showed improvement in brain ChE activity, neurotransmitter levels and reduction in IL-6 and TNF-α levels.

CONCLUSION

The present study demonstrates that treatment with cinnamaldehyde reverse neuroinflammation and changes in neurotransmitter levels, and consequently improves behavioral deficits in diabetic rats.