Anti-inflammatory effects of resolvins in diabetic nephropathy: Mechanistic pathways

Sodium-glucose cotransporter 2 inhibitors and renin-angiotensin-aldosterone system, possible cellular interactions and benefits

Sodium glucose cotransporter 2 inhibitors (SGLT2is) are a newly developed class of anti-diabetics which exert potent hypoglycemic effects in the diabetic milieu. However, the evidence suggests that they also have extra-glycemic effects. The renin-angiotensin-aldosterone system (RAAS) is a hormonal system widely distributed in the body that is important for water and electrolyte homeostasis as well as renal and cardiovascular function. Therefore, modulating RAAS activity is a main goal in patients, notably diabetic patients, which are at higher risk of complications involving these organ systems. Some studies have suggested that SGLT2is have modulatory effects on RAAS activity in addition to their hypoglycemic effects and, thus, these drugs can be considered as promising therapeutic agents for renal and cardiovascular disorders. However, the exact molecular interactions between SGLT2 inhibition and RAAS activity are not clearly understood. Therefore, in the current study we surveyed the literature for possible molecular mechanisms by which SGLT2is modulate RAAS activity.

Anti-inflammatory benefits of semaglutide: State of the art

Individuals with diabetes often have chronic inflammation and high levels of inflammatory cytokines, leading to insulin resistance and complications. Anti-inflammatory agents are proposed to prevent these issues, including using antidiabetic medications with anti-inflammatory properties like semaglutide, a GLP-1 analogue. Semaglutide not only lowers glucose but also shows potential anti-inflammatory effects. Studies suggest it can modulate inflammatory responses and benefit those with diabetes. However, the exact mechanisms of its anti-inflammatory effects are not fully understood. This review aims to discuss the latest findings on semaglutide's anti-inflammatory effects and the potential pathways involved.

Resolvin D1 Inhibits IL-6-Induced Epithelial-Mesenchymal Transition of Colorectal Cancer Cells by Targeting IL-6/STAT3 Signaling

Colorectal cancer (CRC) has emerged as a prevalent malignancy worldwide, exhibiting the high morbidity and mortality rates. Resolvin D1 (RvD1) can exert anti-inflammation and anti-cancer effects on various diseases. This study is aimed to explore the role of RvD1 in CRC cells. HCT15 and SW480 cells were stimulated with IL-6 in our study. A series of assays such as CCK-8, colony formation, wound healing, Transwell, Western blotting, and immunofluorescence staining were designed and conducted to figure out the role of RvD1 in CRC cells. RvD1 suppressed IL-6-induced SW480 and HCT15 cell proliferation. In addition, RvD1 inhibited IL-6-induced SW480 and HCT15 cell migration, invasion, and EMT process. In mechanism, RvD1 inhibited the activation of IL-6/STAT3 signaling in SW480 and HCT15 cells. Angoline strengthened the inhibitive effect of RvD1 on cell malignancy. RvD1 inhibited cell growth, migration, invasion and EMT process by inactivating IL-6/STAT3 signaling in CRC.

Development of New Resolvin D1 Analogues for Osteoarthritis Therapy: Acellular and Computational Approaches to Study Their Antioxidant Activities

In osteoarthritis (OA), oxidative stress plays a crucial role in maintaining and sustaining cartilage degradation. Current OA management requires a combination of pharmaceutical and non-pharmacological strategies, including intraarticular injections of hyaluronic acid (HA). However, several lines of evidence reported that HA oxidation by reactive oxygen species (ROS) is linked with HA cleavage and fragmentation, resulting in reduced HA viscosity. Resolvin D1 (RvD1) is a lipid mediator that is biosynthesized from omega-3 polyunsaturated fatty acids and is a good candidate with the potential to regulate a panoply of biological processes, including tissue repair, inflammation, oxidative stress, and cell death in OA. Herein, newly designed and synthesized imidazole-derived RvD1 analogues were introduced to compare their potential antioxidant properties with commercially available RvD1. Their antioxidant capacities were investigated by several in vitro chemical assays including oxygen radical absorbance capacity, 2,2-diphenyl-1-picrylhydrazyl radical scavenging, ferric ion reducing antioxidant power, hydroxyl radical scavenging, and HA fragmentation assay. All results proved that imidazole-derived RvD1 analogues showed excellent antioxidant performance compared to RvD1 due to their structural modifications. Interestingly, they scavenged the formed reactive oxygen species (ROS) and protected HA from degradation, as verified by agarose gel electrophoresis and gel permission chromatography. A computational study using Gaussian 09 with DFT calculations and a B3LYP/6-31 G (d, p) basis set was also employed to study the relationship between the antioxidant properties and chemical structures as well as calculation of the molecular structures, frontier orbital energy, molecular electrostatic potential, and bond length. The results showed that the antioxidant activity of our analogues was higher than that of RvD1. In conclusion, the findings suggest that imidazole-derived RvD1 analogues can be good candidates as antioxidant molecules for the treatment of oxidative stress-related diseases like OA. Therefore, they can prolong the longevity of HA in the knee and thus may improve the mobility of the articulation.

Nephroprotective Effect of Ferula assa-foetida Oleo Gum Resin on Type 2 Diabetic Rats

OBJECTIVE

Diabetic nephropathy is one of the main causes of kidney failure in the end stage of diabetes worldwide. On the other hand, asafoetida is a gum whose hypoglycemic effects have been proven. The present study was conducted with the aim of using asafoetida to prevent diabetic nephropathy.

METHODS

Diabetes was induced by a high-fat diet (60%) and streptozotocin injection (35 mg/kg) in rats. Diabetic rats were treated with an oral dose of 50 mg/kg of asafoetida for 8 weeks. At the end of the experiment, serum and urine parameters were examined. Antioxidant enzymes and lipid peroxidation levels in the kidney were also determined along with its histological examination. The expression levels of tumor necrosis factor-alpha and Transforming growth factor beta genes were also evaluated.

RESULTS

Glucose, cholesterol, triglyceride, and HbA1c concentrations were significantly reduced in the asafoetida 50. On the other hand, in the treatment group, serum creatinine, urea, and albumin levels decreased and increased in urine. Antioxidant enzymes in the kidney improved significantly, and the expression of tumour necrosis factor-alpha and transforming growth factor-beta genes decreased. Histopathological examination also showed that necrosis, epithelial damage, and leukocyte infiltration increased in the diabetic and decreased in the treatment group.

CONCLUSION

The result of biochemical analysis, enzymatic, and histological examinations showed that asafoetida may delay the progression of diabetic nephropathy due to the presence of anti-inflammatory and antioxidant activities.

Discovering a trans-omics biomarker signature that predisposes high risk diabetic patients to diabetic kidney disease

Diabetic kidney disease is the leading cause of end-stage kidney disease worldwide; however, the integration of high-dimensional trans-omics data to predict this diabetic complication is rare. We develop artificial intelligence (AI)-assisted models using machine learning algorithms to identify a biomarker signature that predisposes high risk patients with diabetes mellitus (DM) to diabetic kidney disease based on clinical information, untargeted metabolomics, targeted lipidomics and genome-wide single nucleotide polymorphism (SNP) datasets. This involves 618 individuals who are split into training and testing cohorts of 557 and 61 subjects, respectively. Three models are developed. In model 1, the top 20 features selected by AI give an accuracy rate of 0.83 and an area under curve (AUC) of 0.89 when differentiating DM and non-DM individuals. In model 2, among DM patients, a biomarker signature of 10 AI-selected features gives an accuracy rate of 0.70 and an AUC of 0.76 when identifying subjects at high risk of renal impairment. In model 3, among non-DM patients, a biomarker signature of 25 AI-selected features gives an accuracy rate of 0.82 and an AUC of 0.76 when pinpointing subjects at high risk of chronic kidney disease. In addition, the performance of the three models is rigorously verified using an independent validation cohort. Intriguingly, analysis of the protein-protein interaction network of the genes containing the identified SNPs (RPTOR, CLPTM1L, ALDH1L1, LY6D, PCDH9, B3GNTL1, CDS1, ADCYAP and FAM53A) reveals that, at the molecular level, there seems to be interconnected factors that have an effect on the progression of renal impairment among DM patients. In conclusion, our findings reveal the potential of employing machine learning algorithms to augment traditional methods and our findings suggest what molecular mechanisms may underlie the complex interaction between DM and chronic kidney disease. Moreover, the development of our AI-assisted models will improve precision when diagnosing renal impairment in predisposed patients, both DM and non-DM. Finally, a large prospective cohort study is needed to validate the clinical utility and mechanistic implications of these biomarker signatures.

Induction of Pyroptosis in Renal Tubular Epithelial Cells Using High Glucose

Background

The micro-inflammatory state is important for the occurrence of diabetic kidney disease (DKD). Here, we aimed to explore the expression of pyroptosis related indicators and ultrastructural characteristics in DKD, and investigate pyroptosis in renal tubular epithelial cells induced by high glucose.

Methods

Immunohistochemistry was used to detect expression of the inflammation-related protein NOD-like receptor protein 3 (NLRP3) and pyroptosis key protein gasdermin D (GSDMD) in kidney tissues of DKD patients. HK-2 cells were cultured in vitro and stimulated with different concentrations of glucose. The changes in HK-2 cell ultrastructure were observed using electronmicroscopy, and western blot was used to detect NLRP3, caspase-1 p20, GSDMD-N, interleukin (IL)-1β, and IL-18 expression.

Results

NLRP3 and GSDMD expression in kidney tissues of DKD patients was higher than that in control subjects. Further, GSDMD expression was positively correlated with that of NLRP3 (r = 0.847, P = 0.02). After stimulating HK-2 cells for 24 h with different glucose concentrations, compared with the control group, the 15 and 30 mmol/L glucose groups showed typical ultrastructural changes of pyroptosis. The protein expression of NLRP3, caspase-1 p20, GSDMD-N, IL-1β, and IL-18 expression in high glucose group increased significantly compared with the control group, and was glucose-concentration-dependent.

Conclusion

High glucose can activate inflammasome, cause inflammatory cytokines release, and induce pyroptosis in HK-2 cells. NLRP3-caspase-1 may be involved in GSDMD-mediated pyroptosis. This study shows a novel relationship between glucose concentration and pyroptosis, which can be studied further to design better therapies for patients with DKD.

Icariin protects podocytes from NLRP3 activation by Sesn2-induced mitophagy through the Keap1-Nrf2/HO-1 axis in diabetic nephropathy

BACKGROUND

Icariin (ICA) is a flavonoid extract obtained from Herba epimedii that has been proven to exert multiple pharmacological activities, including antifibrotic and anti-inflammatory activities.

PURPOSE

This study aimed to investigate the ameliorative mechanism of ICA in diabetes mellitus rats and MPC-5 cells.

METHODS

We administered ICA at 3 different dosages (20 mg/kg, 40 mg/kg, 80 mg/kg) to streptozotocin (STZ)-treated rats and (1 μM, 3 μM, 10 μM) to high glucose (HG)-treated MPC-5 cells. We also chose irbesartan (IRB) (13.5 mg/kg in rats, 1 μM in cells) as a positive control drug to evaluate the ICA pharmacological effect. After administration, the kidneys of rats and MPC-5 cells were harvested for experiments.

RESULTS

After 8 weeks of oral administration, we found that the physiological index was improved by ICA and IRB. The results of immunohistochemistry, Western blot, and laser confocal imaging showed that mitophagy might play a key role in ICA-induced improvement. In further research, we found that ICA could activate Nrf2, suppress NLRP3 and degrade Keap1 via Sesn2-dependant mitophagy. To verify our hypothesis, we blocked the mitophagy signalling pathway via Sesn2 siRNA. The results showed that ICA-induced NLRP3 suppression and mitophagy vanished.

CONCLUSION

In summary, we conclude that ICA can increase Sesn2-induced mitophagy to inhibit NLRP3 inflammasome activation by the Keap1-Nrf2/HO-1 axis in diabetic nephropathy rats. This might be the underlying mechanism of ICA's protective effect in diabetic nephropathy.

Autophagy as a molecular target of quercetin underlying its protective effects in human diseases

Autophagy, known as a "self-eating" process, is associated with degradation of aged or damaged components and organelles. Generally, autophagy is a survival mechanism that provides energy during nutritional deprivation. This mechanism plays a remarkable role during the physiological condition by maintaining homeostasis and energy balance and several pathological conditions, particularly neurological disorders. Due to the critical role of autophagy in cancer, much attention has been made in the regulation of autophagy using both naturally occurring and synthetic drugs. Quercetin is a plant-derived chemical belonging to the family of flavonoids. Quercetin has valuable biological and therapeutic effects such as anti-tumor, antioxidant, anti-inflammatory, anti-diabetic, hepatoprotective, and cardioprotective. At the present review, we first provide an introduction about quercetin and autophagy with its related molecular pathways. We also describe how quercetin modulates autophagy mechanism to exert its therapeutic effects.

The association between serum interleukin-1 beta and heparin sulphate in diabetic nephropathy patients

Inflammation is considered an important mechanism in the development of diabetes mellitus (DM) and persists for a long time before the occurrence of diabetic nephropathy (DN). Many studies have demonstrated that a decrease in the endothelial glycocalyx (EG) is negatively correlated with proteinuria. To elucidate whether EG damage induced by inflammasomes in DM patients leads to the occurrence of microalbuminuria (MA) and accelerates the progression of DN, this study screened 300 diagnosed DM patients. Finally, 70 type 2 diabetes patients were invited to participate in this study and were divided into two groups: the T2DM group (patients with normal MA and without diabetic retinopathy, n = 35) and the T2DN group (patients with increased MA and diabetic retinopathy, n = 35). Circulating heparin sulphate (HS, EG biomarkers) and interleukin-1 beta (IL-1β, inflammasome biomarkers) of the patients were measured by ELISA. Laboratory data were measured using routine laboratory methods. Patients in the T2DN group had increased serum HS, increased IL-1β, increased CRP, decreased haemoglobin, and increased neutrophils compared to patients in the T2DM group (all P < 0.05). Increased HS and decreased haemoglobin were independently associated with T2DN patients. ROC curves showed that the AUC of HS for the prediction of T2DN was 0.67 (P < 0.05). The combination of HS and haemoglobin yielded a significant increasement in the AUC (0.75, P < 0.001) with optimal sensitivity (71.2%) and specificity (79%). Furthermore, serum IL-1β was positively correlated with HS and was an independent associated factor of HS in the T2DN group. The relationship between HS and IL-1β was not significant in the T2DM group. Our findings surgessed the inflammasome may be associated with and promote damage to the EG during the disease course of DN that manifests as increased MA.

Renoprotective Roles of Curcumin

The use of herb-based therapies is increasing over the past decades. These agents have been reported to provide many beneficial effects in many experimental and clinical studies. Curcumin is one of these agents which has potent pharmacological effects enabling it for the prevent and treatment of many diseases and pathologies such as renal disorders, hyperglycemia, oxidative stress, hypertension, and dyslipidemia. However, the exact molecular mechanisms mediating these renoprotective effects of curcumin are not well established. So, in the current study, we surveyed for possible renoprotective roles of curcumin and concluded how curcumin protects against renal injuries.

Insights in diabetes: Molecular mechanisms-Protectin DX, an anti-inflammatory and a stimulator of inflammation resolution metabolite of docosahexaenoic acid, protects against the development of streptozotocin-induced type 1 and type 2 diabetes mellitus in male Swiss albino mice

Our previous studies revealed that certain endogenous low molecular weight lipids have potent anti-diabetic actions. Of all, arachidonic acid (AA) and its anti-inflammatory and inflammation resolving metabolite lipoxin A4 (LXA4) are the most potent anti-diabetic molecules. Similar anti-diabetic action is also shown by resolvins. In our efforts to identify other similar lipid based anti-diabetic molecules, we investigated potential anti-diabetic action of protectin DX that also has anti-inflammatory and inducer of inflammation resolution action(s) like LXA4. Protectin DX {10(S),17(S)-dihydroxy-4Z,7Z,11E,13Z,15E,19Z-docosahexaenoic acid, also called as 10(S),17(S)-DiHDoHE)} prevented the development of streptozotocin-induced type 1 and type 2 diabetes mellitus in Swiss male albino mice. Protectin DX showed potent anti-inflammatory, antioxidant and anti-apoptotic actions that could explain its anti-diabetic action. In view of these beneficial actions, efforts need to be developed to exploit PDX and other similar compounds as potential anti-diabetic molecule in humans.

LINC00323 mediates the role of M1 macrophage polarization in diabetic nephropathy through PI3K/AKT signaling pathway

OBJECTIVE

To explore the effect of LINC00323 on the polarization of M1 macrophages in diabetic nephropathy. To study the effect and biological mechanism of LINC00323 on the occurrence and development of diabetic nephropathy.

METHODS

We used clinical samples to analyze the correlation between macrophage polarization and the occurrence and development of diabetic nephropathy. In addition, we used bioinformatics to analyze the key molecules of macrophage polarization. We then verified the key pathways that promote the M1 polarization of macrophages at the level of cell biology. And we verify the effectiveness of treatment against this target in animal experiments.

RESULTS

We analyzed in clinical samples that the expression of inflammatory factors (TNF-α and IL-6) increased in patients with diabetic nephropathy. In addition, we found that the expression of M1 marker protein CD86 increased through PCR and western blot analysis. We found a key target (LINC00323) through bioinformatics. The expression of LINC00323 in patients' blood samples is also at a high level. We further explored the mechanism of LINC00323 involved in the polarization of M1 macrophages at the level of cellular molecular biology, and found that it is closely related to the PI3K/AKT signaling pathway. In animal models, we found that inhibiting the expression of LINC00323 can reduce the damage of diabetic nephropathy.

CONCLUSION

We found that LINC00323 mediates the polarization of M1 macrophages through the PI3K/AKT signaling pathway. LINC00323 plays an important role in the occurrence and development of diabetic nephropathy.

Protective Effect of Yi Shen Pai Du Formula against Diabetic Kidney Injury via Inhibition of Oxidative Stress, Inflammation, and Epithelial-to-Mesenchymal Transition in db/db Mice

OBJECTIVE

Diabetic kidney disease (DKD) is one of the most common chronic microvascular complications of diabetes; however, there remains a lack of effective therapeutic strategies. Yi Shen Pai Du Formula (YSPDF), a traditional Chinese medicine preparation, has been clinically used in treating chronic kidney disease (CKD) for more than 20 years. However, whether YSPDF has a therapeutic effect on DKD has not been studied.

METHODS

This study was conducted to investigate the effect of YSPDF administration on db/db mice, a model of type 2 diabetes that develops DKD, and reveal its underlying mechanism of action through a high glucose- (HG-) induced renal injury cell model.

RESULTS

We found that YSPDF significantly improved numerous biochemical parameters (fasting blood glucose, serum creatinine, blood urea nitrogen, 24 h urine total protein, total cholesterol, and total triglycerides) and ameliorated the abnormal histology and fibrosis of renal tissue. Moreover, the status of oxidative stress and levels of inflammatory cytokines (TNF-α, IL-6, IL-1β, and MCP-1) were markedly inhibited by YSPDF treatment. YSPDF treatment significantly mitigated renal fibrosis, with evidence suggesting that this was by inhibiting epithelial-to-mesenchymal transition (EMT) via suppression of the TGF-β1/Smad pathway. Interestingly, the expression of Nrf2, HO-1, and NQO1, proteins known to be associated with oxidative stress, were significantly increased upon administration of YSPDF. The levels of NLRP3 inflammasome proteins, including NLRP3, ASC, caspase-1, and cleaved caspase-1 were decreased in the YSPDF-treated group. Cell experiments showed that YSPDF inhibited EMT and the NLRP3 inflammasome in HG-exposed HK-2 cells, possibly via activation of Nrf2.

CONCLUSION

Our study indicates that YSPDF may ameliorate renal damage in db/db mice via inhibition of oxidative stress, inflammation, and EMT, with the mechanism potentially being related to the activation of the Nrf2 pathway.

Icariin ameliorates streptozocin-induced diabetic nephropathy through suppressing the TLR4/NF-κB signal pathway

Diabetic nephropathy (DN) is one of the complex and severe complications of diabetes mellitus (DM). Icariin (ICA) is a flavonoid extracted from the leaves and stems of Herba epimedii with a wide range of pharmacological effects, such as anti-osteoporosis, anti-fibrosis, anti-aging, anti-inflammation and antioxidation. The purpose of our study was to explore the renal protective effect of ICA on DN in mice and its possible mechanisms. ICR mice were exposed to STZ-induced DN. The kidney organ coefficient of mice was computed. 24 h UP in urine was measured. Serum FBG, Cr and BUN were detected. The content of MDA and the activities of SOD, CAT and GSH-Px in renal tissues were tested. HE staining, PAS staining, PASM staining and transmission electron microscopy were used to observe renal pathological changes. Furthermore, TLR4, p-NF-κB p65, TNF-α and IL-6 of renal tissues were assayed by immunohistochemistry and western blotting. Our results indicated that ICA observably optimized the renal organ coefficient, reduced the level of 24 h UP in urine, decreased the content of Cr, BUN in serum and MDA in renal tissues, promoted the activities of SOD, CAT and GSH-Px in renal tissues, and ameliorated pathological lesions of kidneys noticeably. Besides, ICA inhibited the expressions of TLR4, p-NF-κB p65, TNF-α and IL-6 remarkably in renal tissues. ICA, which might lighten the renal inflammatory response by suppressing the TLR4/NF-κB signal pathway, played a protective role in kidneys of STZ-induced DN mice.

Efonidipine Exerts Cerebroprotective Effect by Down-regulation of TGF-β/SMAD-2-Dependent Signaling Pathway in Diabetic Rats

Calcium overload and hyperglycemia are risks of stroke onset in diabetics. Our study was designed to elucidate the beneficial role of calcium channel blockers by targeting voltage-gated calcium channels in diabetes-associated cerebrovascular complications. Diabetes was induced using the neonatal streptozotocin rat model. After confirmation of diabetes, middle cerebral artery occlusion (MCAO) was carried out. The pre-treatment with 1 mg/kg/day efonidipine was administered for the period of 4 weeks. After 24 h of ischemic induction surgery, the neurological score was determined, and blood was collected for determination of biochemical parameters. Treatment with efonidipine showed a significant reduction in post-ischemic brain infract volume, brain hemisphere weight difference, neurological score, Na⁺-K⁺ ATPase activity, serum CK-MB, and LDH levels in normoglycemic and hyperglycemic MCAO-induced animals. While no significant changes in glucose and lipid levels were observed by treatment, efonidipine significantly decreased the levels of malondialdehyde, acetylcholine esterase, and nitrite levels and increased the levels of antioxidant markers in both normoglycemic and hyperglycemic MCAO animals. TGF-β and VEGF were found to be down-regulated after treatment with efonidipine in gene expression study. In conclusion, the study data supports the cerebroprotective role of efonidipine in diabetic animals possibly through TGF-β/SMAD-2 signaling pathway.

Biological and Therapeutic Effects of Troxerutin: Molecular Signaling Pathways Come into View

Flavonoids consist a wide range of naturally occurring compounds which are exclusively found in different fruits and vegetables. These medicinal herbs have a number of favourable biological and therapeutic activities such as antioxidant, neuroprotective, renoprotective, anti-inflammatory, anti-diabetic and anti-tumor. Troxerutin, also known as vitamin P4, is a naturally occurring flavonoid which is isolated from tea, coffee and cereal grains as well as vegetables. It has a variety of valuable pharmacological and therapeutic activities including antioxidant, anti-inflammatory, anti-diabetic and anti-tumor. These pharmacological impacts have been demonstrated in in vitro and in vivo studies. Also, clinical trials have revealed the efficacy of troxerutin for management of phlebocholosis and hemorrhoidal diseases. In the present review, we focus on the therapeutic effects and biological activities of troxerutin as well as its molecular signaling pathways.

Role of Circular RNA in Kidney-Related Diseases

The kidney is vital in maintaining fluid, electrolyte, and acid–base balance. Kidney-related diseases, which are an increasing public health issue, can happen to people of any age and at any time. Circular RNAs (circRNAs) are endogenous RNA that are produced by selective RNA splicing and are involved in progression of various diseases. Studies have shown that various kidney diseases, including renal cell carcinoma, acute kidney injury, and chronic kidney disease, are linked to circRNAs. This review outlines the characteristics and biological functions of circRNAs and discusses specific studies that provide insights into the function and potential of circRNAs for application in the diagnosis and treatment of kidney-related diseases.

A unique radioprotective effect of resolvin E1 reduces irradiation-induced damage to the inner ear by inhibiting the inflammatory response

Background

In addition to the direct effects of irradiation, the induced inflammatory response may play an important role in the damage to the inner ear caused by radiotherapy for the treatment of head and neck cancers. Resolvin E1 (RvE1) has anti-inflammatory activity, acting by reducing neutrophil infiltration and proinflammatory cytokine expression. Therefore, in this study we sought to confirm whether the inflammation induced by irradiation was involved in damage to the inner ear after radiotherapy and to investigate the protective effect and underlying mechanism of RvE1 using mouse models.

Methods

A dose of RvE1 was delivered by intraperitoneal injection to mice before irradiation. Changes in the auditory brainstem response (ABR), relative balance ability, inner ear morphology and the expression levels of inflammatory factors in the inner ear were analyzed on days 7 and 14 after irradiation and compared among different experimental groups.

Results

Changes of ABR and relative balance ability showed the inner functions of experimental mice presented severe damage after irradiation, but the damage was significantly alleviated after RvE1 pretreatment compared to irradiation alone. Morphological analysis of the inner ear showed severe damage to the cochlea and vestibule after irradiation. In contrast, damage to the cochlea and vestibule was significantly reduced in the RvE1-pretreated group compared to that in the irradiation alone group. Along with these functional and morphological changes, the mRNA expression level of anti-inflammatory factors interleukin-2 was significantly increased, while those of proinflammatory factors interleukin-6 and tumor necrosis factor-α were significantly decreased in the inner ear of mice after RvE1 pretreatment compared to irradiation alone.

Conclusions

We believe that inflammation induced by irradiation is involved in the damage to the inner ear caused by radiotherapy, and that RvE1 reduces the damage caused by irradiation to the inner ear by regulating the induced inflammatory response.

Resolvin D1 protects against sepsis-induced cardiac injury in mice

Increased inflammation is the key mechanism that mediates sepsis induced cardiac injury. Resolvin D1 (RvD1), a bioactive lipid mediator synthesized from docosahexaenoic acid, can attenuate the severity of many inflammation-related diseases through anti-inflammatory and pro-resolving properties. However, the protective role of RvD1 in sepsis induced cardiac injury remains unclear. Mice were randomly divided into three groups: the control group, LPS group and RvD1 + LPS group. LPS (10 mg/kg, i.p.) was used to establish a sepsis-induced cardiac injury model. RvD1 (5 ug/kg, i.p.) was injected 30 min before LPS injection. RvD1 treatment significantly attenuated the deteriorated cardiac function and cardiac injury induced by LPS, as evidenced by the improved left ventricular ejection fraction, serum levels of cardiac injury markers and severity of cardiomyocyte apoptosis. In addition, RvD1 treatment significantly attenuated the infiltration of pro-inflammatory M1 macrophages and expression of inflammatory cytokines in the heart. Mechanistically, the attenuated activation of NK-κB and MAPK signaling mediated the anti-inflammatory and antiapoptotic effects of RvD1. In addition, LPS-induced infiltration of neutrophils and M1 macrophages in the spleen was significantly attenuated by the RvD1 treatment. Results of the present study suggest that RvD1 protects the heart against LPS-induced injuries by attenuating the local and systemic inflammatory response, highlighting the therapeutic effects of RvD1 in sepsis-induced cardiac injury.

Cyclocarya paliurus ethanol leaf extracts protect against diabetic cardiomyopathy in db/db mice via regulating PI3K/Akt/NF-κB signaling

Background

Diabetic cardiomyopathy (DCM) is a serious complication of diabetes that can lead to significant mortality. Cyclocarya paliurus is a tree, the leaves of which are often utilized to prevent and treat diabetes mellitus. Whether C. paliurus leaves can prevent or treat DCM, however, it remains to be formally assessed. The present study was therefore designed to assess the ability of C. paliurus to protect against DCM in db/db mice.

Methods

Male wild-type (WT) and db/db mice were administered C. paliurus ethanol leaf extracts (ECL) or appropriate vehicle controls daily via gavage, and levels of blood glucose in treated animals were assessed on a weekly basis. After a 10-week treatment, the levels of cardiac troponin I (cTn-I), lactate dehydrogenase (LDH), creatine kinase MB (CK-MB), aspartate transaminase (AST), total triglycerides (TG), and total cholesterol (TC) in serum were measured. Activities of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) and the levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6 in heart tissues were detected. Hematoxylin-eosin (HE) and Masson staining were conducted. The protein expression that related with oxidative stress and inflammatory reaction was evaluated by Western blotting.

Results

Compared with WT mice, the TG, TC, and blood glucose levels in db/db mice increased significantly, which were reduced by ECL treatment. Compared with WT mice, the levels of LDH, CK-MB, AST, and cTn-I in serum and MDA in heart tissues of db/db mice increased significantly. Activities of SOD, GSH-Px, and CAT in heart tissues of db/db mice decreased significantly. The levels of inflammatory cytokines (TNF-α, IL-1β, and IL-6) in heart tissues of db/db mice increased remarkably. However, ECL treatment improved the above pathological changes significantly. ECL alleviated pathological injury and fibrosis in heart tissues of mice. Western blotting showed that ECL increased Bcl-2 level and decreased Bax, cle-caspase-3, and cle-caspase-9 expression. Furthermore, ECL inhibited NF-κB nuclear translocation and increased PI3K and p-Akt expressions.

Conclusion

Our results indicate that ECL treatment can markedly reduce pathological cardiac damage in db/db mice through antiapoptotic, antifibrotic, and anti-inflammatory mechanisms. Specifically, this extract was able to suppress NF-κB activation via the PI3K/Akt signaling pathway. Given its diverse activities and lack of significant side effects, ECL may thus have therapeutic value for the treatment of DCM.

Role and Mechanism of Maresin-1 in Acute Lung Injury Induced by Trauma-Hemorrhagic Shock

Background

It is reported that trauma hemorrhagic shock (THS) could resulted in organ injury and is related to a high mortality rate. Maresin-1 (MaR1), a derived medium through biosynthesis, is involved in inflammatory responses. However, the mechanism of MaR1 against acute lung injury needs to be further understood. This report aimed to explore whether MaR1 had a protective effect on lung injury.

Material/Methods

We constructed a THS-induced acute lung damage rat model and then treated the rats with MaR1. We determined Evan’s blue dye (EBD) lung permeability, lung permeability index, wet/dry (W/D) weight ratio, nitric oxide (NO) concentration and inducible nitric oxide synthase (iNOS) expression in lung tissue samples. The inflammation-related cytokines levels in the bronchoalveolar lavage fluid (BALF) and serum of rats were determined by enzyme-linked immunosorbent assay (ELISA). Finally, the TLR4/p38MAPK/NF-κB pathway was analyzed by quantitative real-time polymerase chain reaction and western blot assay.

Results

The increased EBD ratio, lung permeability index and W/D weight ratio, NO concentration and iNOS levels were suppressed by MaR1 treatment. THS-induced over-production of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in BALF and serum was suppressed by MaR1. Besides, the TLR4/p38MAPK/NF-κB pathway activation in THS-induced rats were inhibited by MaR1 treatment.

Conclusions

Our study showed that MaR1 could effectively alleviated THS-induced lung injury via inhibiting the excitation of the TLR4/p38MAPK/NF-κB pathway in THS-induced rats, suggesting that MaR1 might be a novel agent for lung damage treatment.

The Mechanism of Contrast-Induced Acute Kidney Injury and Its Association with Diabetes Mellitus

Contrast-induced acute kidney injury (CI-AKI) is the third most common hospital-acquired AKI after AKI induced by renal perfusion insufficiency and nephrotoxic drugs, taking great adverse effects on the prognosis and increasing hospital stay and medical cost. Diabetes nephropathy (DN) is a common chronic complication of DM (diabetes mellitus), and DN is an independent risk factor for chronic kidney disease (CKD) and CI-AKI. The incidence of CI-AKI significantly increases in patients with renal injury, especially in DM-related nephropathy. The etiology of CI-AKI is not fully clear, and research studies on how DM becomes a facilitated factor of CI-AKI are limited. This review describes the mechanism from three aspects. ① Pathophysiological changes of CI-AKI in kidney under high-glucose status (HGS). HGS can enhance the oxidative stress and increase ROS which next causes stronger vessel constriction and insufficient oxygen supply in kidney via vasoactive substances. HGS also aggravates some ion pump load and the latter increases oxygen consumption. CI-AKI and HGS are mutually causal, making the kidney function continue to decline. ② Immunological changes of DM promoting CI-AKI. Some innate immune cells and pattern recognition receptors (PRRs) in DM and/or DN may respond to some damage-associated molecular patterns (DAMPs) formed by CI-AKI. These effects overlap with some pathophysiological changes in hyperglycemia. ③ Signaling pathways related to both CI-AKI and DM. These pathways involved in CI-AKI are closely associated with apoptosis, inflammation, and ROS production, and some studies suggest that these pathways may be potential targets for alleviating CI-AKI. In conclusion, the pathogenesis of CI-AKI and the mechanism of DM as a predisposing factor for CI-AKI, especially signaling pathways, need further investigation to provide new clinical approaches to prevent and treat CI-AKI.

Tanshinone IIA inhibits osteosarcoma growth through modulation of AMPK-Nrf2 signaling pathway

Tanshinone IIA (Tan IIA) is a member of the major lipophilic components extracted from the root of Salvia miltiorrhiza Bunge. Osteosarcomas are primary malignant tumors of bone. The aim of our study is to explore the role of Tan IIA in osteosarcomas survival, migration, and proliferation. MG63 osteosarcoma cell line was cultured in vitro and treated with different concentrations of Tan IIA. Then, ELISA, immunofluorescence, qPCR, western blots, and pathway analysis were conducted to verify whether Tan II modulated osteosarcoma survival, migration, and proliferation through the AMPK/Nrf2 signaling pathway. Our results indicated that Tan IIA dose-dependently inhibited MG63 osteosarcoma cell survival, migration, and proliferation. Mechanistically, Tan IIA reduced cell viability and inhibited the transcriptions of migratory factors. In addition, the number of proliferative MG63 osteosarcoma cell was also reduced by Tan IIA. Molecular investigations demonstrated that Tan IIA treatment caused a drop in the transcriptions and activities of AMPK and Nrf2. Interestingly, knockdown of AMPK and Nrf2 markedly attenuated MG63 osteosarcoma cell survival, migration, and proliferation. Altogether, our results indicate that Tan IIA could be used as an effective anticancer drug to control osteosarcoma proliferation through affecting its survival, migration, and proliferation.

Protective effect of ferulic acid on STZ-induced diabetic nephropathy in rats

Ferulic acid protects against diabetic nephropathy in STZ-induced rats by attenuating oxidative stress, inflammation, fibrosis and podocyte injury.

Novel biphenyl diester derivative AB-38b inhibits NLRP3 inflammasome through Nrf2 activation in diabetic nephropathy

Inflammation reaction mediated by NLRP3 inflammasome and Nrf2-related oxidative stress are vital participants in the development of diabetic nephropathy (DN) and closely associated to kidney fibrosis. Nrf2, a known antioxidative transcription factor, has been reported to activate NLRP3 inflammasome through its downstream factors (HO-1, NQO1, etc.) recently. AB38b is a newly synthesized biphenyl diester derivative with a Nrf2 activation property. This research aims to evaluate the renal protective effects of AB-38b and to elucidate the anti-inflammation mechanisms involved. Type 2 diabetic mice induced by high fat diet with streptozocin (STZ) and high glucose-cultured mouse glomerular mesangial cells (GMCs) were used in current study. Results showed that administration of AB-38b improved the kidney function while attenuated renal fibrosis progression in diabetic mice together with reducing the extracellular matrix (ECM) accumulation of GMCs cultured in high glucose. Mechanistically, treatment with AB-38b significantly decreased the high level of NLRP3 inflammasome in diabetic condition by inhibiting the ROS/TXNIP/NLRP3 signaling pathway. And meanwhile, AB-38b treatment effectively improved Nrf2 signaling during diabetic condition. Furthermore, knocking down the gene expression of Nrf2 by siRNA in GMCs abolished the inhibition effect of AB-38b on NLRP3 inflammasome activation and ECM accumulation. Taken together, our data suggest that AB-38b was able to improve the renal function of diabetic mice, and the NLRP3 inflammasome inhibition effect of AB-38b was responsible for the renal protective effect. Further exploration indicate that Nrf2 plays pivotal role in AB-38b's attenuation of DN progression through inhibiting NLRP3 inflammasome activation.

Zafirlukast, a Cysteinyl Leukotriene Receptor 1 Antagonist, Reduces the Effect of Advanced Glycation End-Products in Rat Renal Mesangial Cells In Vitro

Background

Zafirlukast is an antagonist of cysteinyl leukotriene receptor 1 (CysLTR1). Advanced glycation end-products (AGEs) are formed by the glycation of lipids and proteins in hyperglycemia, including diabetes mellitus. Zafirlukast has not previously been studied in diabetic nephropathy. This study aimed to investigate the effects of zafirlukast on rat renal mesangial cells cultured with AGEs in vitro.

Material/Methods

Mesangial cells were cultured in AGEs (0, 20, 50, 100 μg/ml), and with AGEs (100 μg/ml) and zafirlukast (2.5 μm, 5 μm, and 100 μm). An enzyme-linked immunoassay (ELISA) was used to measure the levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and monocyte chemoattractant protein-1 (MCP-1). Reactive oxygen species (ROS) were assessed by intracellular fluorescence measurement of 2′-7′-dichlorodihydrofluorescein diacetate (DCFH-DA), and detection kits were used to measure malondialdehyde (MDA), lactate dehydrogenase (LDH), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD). Cell apoptosis was assessed by flow cytometry, and Western blot was used to measure protein levels.

Results

In mesangial cells cultured with AGEs, markers of inflammation, oxidative stress, and apoptosis and levels of CysLTR1 increased, and these effects were reduced by zafirlukast in a dose-dependent manner. The effects of zafirlukast as a CysLTR1 antagonist protected mesangial cells from the effects of AGE in vitro.

Conclusions

Zafirlukast, a CysLTR1 antagonist, reduced the levels of inflammatory cytokines, markers of oxidative stress, and cell apoptosis induced by AGE in mesangial cells in a dose-dependent way. Future in vivo studies are needed to investigate the potential role for zafirlukast in models of diabetic nephropathy.

NFκB and Kidney Injury

The global burden of chronic kidney disease will increase during the next century. As NFκB, first described more than 30 years ago, plays a major role in immune and non-immune-mediated diseases and in inflammatory and metabolic disorders, this review article summarizes current knowledge on the role of NFκB in in vivo kidney injury and describes the new and so far not completely understood crosstalk between canonical and non-canonical NFκB pathways in T-lymphocyte activation in renal disease.