A Novel Antimicrobial Peptide, Dermaseptin-SS1, with Anti-Proliferative Activity, Isolated from the Skin Secretion of Phyllomedusa tarsius.

The emergence of multidrug-resistant bacteria has severely increased the burden on the global health system, and such pathogenic infections are considered a great threat to human well-being. Antimicrobial peptides, due to their potent antimicrobial activity and low possibility of inducing resistance, are increasingly attracting great interest. Herein, a novel dermaseptin peptide, named Dermaseptin-SS1 (SS1), was identified from a skin-secretion-derived cDNA library of the South/Central American tarsier leaf frog, Phyllomedusa tarsius, using a 'shotgun' cloning strategy. The chemically synthesized peptide SS1 was found to be broadly effective against Gram-negative bacteria with low haemolytic activity in vitro. A designed synthetic analogue of SS1, named peptide 14V5K, showed lower salt sensitivity and more rapid bacteria killing compared to SS1. Both peptides employed a membrane-targeting mechanism to kill Escherichia coli. The antiproliferative activity of SS1 and its analogues against lung cancer cell lines was found to be significant.

Exenatide improves hypogonadism and attenuates inflammation in diabetic mice by modulating gut microbiota.

With the rising incidence of diabetes and its onset at a younger age, the impact on the male reproductive system has gradually gained attention. Exenatide is a glucagon-like peptide-1 receptor agonist effective in the treatment of diabetes. However, its role in diabetes-induced reproductive complications has rarely been reported. The study aimed to investigate the mechanism by which exenatide improved diabetic hypogonadism by regulating gut microbiota (GM) mediated inflammation. C57BL/6J mice were equally divided into normal control (NC), diabetic model control (DM) and exenatide-treated (Exe) groups. Testicular, pancreatic, colonic, and fecal samples were collected to assess microbiota, morphologic damage, and inflammation. Exenatide significantly reduced the fasting blood glucose (FBG) level in diabetic mice, increased the testosterone level, ameliorated the pathological morphological damage of islet, colon, and testes, and reduced the expression of pro-inflammatory factors, tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-6 in colon and testis. Furthermore, exenatide significantly reduced the abundance of some pathogenic bacteria, such as Streptococcaceae and Erysipelotrichaceae, and increased that of beneficial bacteria Akkermansia. Probiotics, such as Lactobacillus were negatively correlated with TNF-α, nuclear factor-kappa-B (NF-κB), IL-6, and FBG. Conditional pathogenic bacteria such as Escherichia/Shigella Streptococcus were positively correlated with TNF-α, NF-κB, IL-6, and FBG. The fecal bacteria transplantation experiment revealed that the abundance of pathogenic bacteria, Peptostreptococcaceae, significantly decreased from Exe group mice to pseudo-sterile diabetic mice, and the pathological damage to testes was also alleviated. These data suggested the protective effects of exenatide on male reproductive damage induced by diabetes by regulating GM.

A Novel Strategy for the Design of Aurein 1.2 Analogs with Enhanced Bioactivities by Conjunction of Cell-Penetrating Regions.

The rational design modification of membrane-active peptide structures by introducing additional membrane-penetrating regions has become a good strategy for the improvement of action and potency. Aurein 1.2 (GLFDIIKKIAESF-NH2) is a multifunctional antimicrobial peptide isolated from the green and golden bell frog, Litoria aurea, and the southern bell frog Litoria raniformis skin secretions. Its bio-functionality has been widely investigated. However, its lack of a potent action failed to provide aurein 1.2 with a competitive edge for further development as a therapeutic agent for clinical use. Herein, aurein 1.2 was chosen as a template for rational modification to achieve a more potent bio-functionality. KLA-2 (GLFDIIKKLAKLAESF-NH2), which a double KLA region inserted into the sequence, presented a 2-16-fold enhancement of antimicrobial activity, a 2-8-fold greater anti-biofilm activity (including biofilm prevention and eradication), and a 7-fold more potent anti-proliferation activity and hence was regarded as the most broad-spectrum active peptide. Additionally, with respect to antimicrobial activity, the IIKK-modified analog, IK-3 (GLFDIIKKIIKKIIKKI-NH2), also demonstrated a potent enhancement of activity against various pathogens, exhibiting a 2-8-fold enhanced activity compared to the parent peptide. Moreover, the selectivities of KLA-1 and KLA-2 were enhanced significantly. In conclusion, peptide modification, through the introduction of additional membrane penetrating regions, can increase both the potency and activity spectra of natural template peptides, making them suitable candidates for new drug development.

Ginkgolide B alleviates oxidative stress and ferroptosis by inhibiting GPX4 ubiquitination to improve diabetic nephropathy.

Diabetic nephropathy (DN) is the leading cause of end­stage renal disease. Although Ginkgo biloba extract has a protective effect on DN, the protective effect and mechanism of its active ingredient Ginkgolide B (GB) on DN remain unclear. The aim of the present study was to investigate whether GB improves DN via alleviating oxidative stress and ferroptosis by inhibiting GPX4 ubiquitination in PA-G-induced mouse podocytes and DN mice. The study in vitro showed that GB effectively reduced serum total cholesterol, triglyceride concentrations and lipid accumulation in PA-G-induced MPC5 cells. In addition, GB promoted the expression of ferroptosis markers GPX4 and FTH1, while inhibited the expression of TfR1, fibrosis markers α-SMA and Collagen α1, as well as intracellular iron content and ROS levels. Interference of GPX4 expression with siRNA counteracted the effect of GB. And GB inhibited GPX4 ubiquitination in a dose-dependent manner. In vivo the experimental results showed that GB effectively reduced hyperglycemia, serum total cholesterol and triglyceride concentrations, reduced urinary albumin excretion and the number of renal lipid droplets, and improved changes in renal structure in DN mice. GB inhibited the expression of ferroptosis marker TfR1 and fibrosis markers α-SMA and Collagen α1, while promoted the expression of ferroptosis markers GPX4 and FTH1. In conclusion, the results suggested that GB may improve DN via protecting the kidney from ferroptosis and oxidative stress damage by inhibiting the ubiquitination of GPX4. These findings suggested that GB, a natural medicine, may be an effective therapeutic option for DN.

Sodium Butyrate Attenuated Diabetes-Induced Intestinal Inflammation by Modulating Gut Microbiota.

Background: Diabetes mellitus (DM) continues to be one of the world's most costly and complex metabolic disorders. Accumulating evidence has shown that intestinal dysbiosis and associated inflammation can facilitate the onset and progression of DM. In this work, our goal was to investigate how sodium butyrate (SB) controls the gut microbiota to reduce the intestinal inflammation brought on by diabetes. Methods: Male KK-Ay mice were randomized into two groups: the DM model group (intragastric administration of 0.9% normal saline) and the SB treatment group (intragastric administration of 1,000 mg/kg/d SB). The C57BL/6J mice were used as the control group (intragastric administration of 0.9% normal saline). These mice were administered via gavage for 8 weeks. Results: The results revealed that SB-treated mice significantly reduced fasting blood glucose (FBG), body weight, 24 h food and water intake, and improved islet histopathology in DM model mice. SB reduced TNF-α, IL-1ß, and iNOS, whereas it enhanced the expression of the anti-inflammatory Arg-1 marker on intestinal macrophages and the secretion of anti-inflammatory IL-10. Specifically, SB was linked to a marked drop in the expression of the Th17 marker RORγt and a substantial increase in the expression of the Treg marker Foxp3. SB treatment was associated with significant reductions in the levels of Th17-derived cytokines such as IL-17 and IL-6, whereas anti-inflammatory Treg-derived cytokines such as TGF-ß were increased. Additionally, the analysis results from 16S rDNA sequencing suggested that SB significantly reversed the variations in intestinal flora distribution and decreased the relative abundance of Weissella confusa and Anaerotruncus colihominis DSM 17241 at the species level as well as Leuconostocaceae, Streptococcaceae, and Christensenellaceae at the family, genus, and species levels. These distinct florae may serve as a diagnostic biomarker for DM-induced intestinal inflammation. In addition, the heat map of phylum and OTU level revealed a close relationship between DM-induced intestinal inflammation and intestinal microbiota. Conclusions: The present study suggested that SB may reduce DM-induced intestinal inflammation by regulating the gut microbiota.

The Herb Pair Radix Rehmanniae and Cornus Officinalis Attenuated Testicular Damage in Mice With Diabetes Mellitus Through Butyric Acid/Glucagon-Like Peptide-1/Glucagon-Like Peptide-1 Receptor Pathway Mediated by Gut Microbiota.

Growing body of research indicates that Traditional Chinese Medicine (TCM) interact with gut microbiota (GM) after oral administration. Radix Rehmanniae and Cornus Officinalis (RR-CO), a well-known TCM pair, is often used to treat diabetes mellitus (DM) and its complications. The current study aimed to explore the protective effects of RR-CO on DM induced testicular damage by modulating GM. The RR-CO treatments significantly reduced hyperglycemia, ameliorated testicular ultrastructural damage and inflammation in DM model to varying degrees. Additionally, 16S-ribosomal DNA (rDNA) sequencing results showed that RR-CO treatment increased the amount of butyric acid-producing GM, such as Clostridiaceae_1 family, and decreased the abundance of Catabacter, Marvinbryantia, and Helicobacter genera. RR-CO fecal bacteria transplantation (RC-FMT) increased the abundance of Clostridiaceae_1 in the Model FMT (M-FMT) group and ameliorated testicular damage. Furthermore, treatment with RR-CO increased the fecal butyric acid level, serum Glucagon-like peptide-1 (GLP-1) level, and testicular GLP-1 receptor (GLP-1R) expression compared to those in DM mice. Finally, intraperitoneal administration of sodium butyrate (SB) significantly improved the pathological damage to the testis and reduced inflammation in the DM group. These data demonstrated a protective effect of RR-CO on DM-induced testicular damage by modulation of GM, which may be mediated by the butyric acid/GLP/GLP-1R pathway.

Cornuside Alleviates Diabetes Mellitus-Induced Testicular Damage by Modulating the Gut Microbiota.

BACKGROUND: Male reproductive damage, as a common complication of diabetes mellitus (DM), is getting more attention lately. We aimed to explore the protective effects and mechanism of cornuside (Cor) modulating gut microbiota to alleviate diabetes mellitus- (DM-) induced testicular damage. METHODS: KK-Ay mice with reproductive damage were randomly divided into the model and Cor treatment groups, and the C57BL/6J mice were used as the normal group. These mice were orally administered Cor for 8 weeks. RESULTS: Cor administration ameliorated the diabetes-related symptoms of polydipsia and polyphagia and lowered the fasting blood glucose (FBG) level. The results of pathological injury showed that Cor improved testicular lesions (the rupture of seminiferous tubules, degeneration of germ cells, and structural shrinkage and separation from each other) in DM model mice. Cor significantly increased the testis/body weight ratio, testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) levels in KK-Ay mice. Cor also protected from reproductive damage by inhibiting apoptosis in the testes of KK-Ay mice. Moreover, Cor significantly increased the sperm count and sperm motility. Additionally, 16S rDNA sequencing analysis showed that Cor could notably reverse the changes in the distribution of gut microbiota and decrease the abundance of Weissella confusa (Weissella), Clostridium sp. ND2 (Clostridium sensu stricto 1), uncultured bacterium (Roseburia), Anaerotruncus colihominis DSM 17241 (Anaerotruncus), [Clostridium] leptum (Anaerotruncus), unidentified (Ruminococcus 1), and uncultured bacterium (Bilophila), which may be a potential biomarker for diagnosing the testicular injury caused by DM. Meanwhile, the heat map of phylum level suggested that the testicular injury caused by DM is closely related to gut microbiota. CONCLUSIONS: Cor could alleviate DM-induced testicular damage, probably by modulating the gut microbiota.

Catalpol ameliorates endothelial dysfunction and inflammation in diabetic nephropathy via suppression of RAGE/RhoA/ROCK signaling pathway.

Catalpol is an iridoid glycoside compound isolated from the root of Rehmannia glutinosa, which has been reported to be a promising candidate for the treatment of diabetic diseases. The present study aimed at investigating the effects and potential mechanism of catalpol on endothelial dysfunction and inflammation in diabetic nephropathy (DN). We constructed DN mice and advanced glycation end products (AGEs)-induced mouse glomerular endothelial cells (mGECs) injury model. The results demonstrated that catalpol effectively improved renal pathology and decreased levels of urine protein, serum creatinine, and blood urea nitrogen in DN mice. Catalpol significantly reduced endothelial dysfunction and inflammatory infiltration of macrophages in DN mice and AGEs-induced mGECs. To further study the protective mechanism of catalpol, we transfected DN mice with recombinant adeno-associated virus expressing receptor of AGEs (RAGE) and intervened AGEs-induced mGECs with inhibitors. Catalpol reversed endothelial dysfunction and inflammation aggravated by RAGE overexpression in DN mice. Meanwhile, catalpol significantly inhibited the RAGE/Ras homolog gene family member A (RhoA)/Rho-associated kinase (ROCK) pathway in DN mice with RAGE overexpression. Moreover, the combination of catalpol with inhibitors of RAGE, RhoA and ROCK exerted stronger anti-endothelial dysfunction and anti-macrophage infiltration effects on AGEs-induced mGECs compared with catalpol alone. In short, this study indicated that catalpol could ameliorate endothelial dysfunction and inflammation via suppression of RAGE/RhoA/ROCK pathway, hereby delaying the progression of DN.

Combination of the Herbs Radix Rehmanniae and Cornus Officinalis Mitigated Testicular Damage From Diabetes Mellitus by Enhancing Glycolysis via the AGEs/RAGE/HIF-1α Axis.

Radix Rehmanniae and Cornus Officinalis (RR-CO) have been widely used as "nourishing Yin and tonifying kidney" herb pairs for the treatment of diabetes mellitus (DM) and its complications in traditional Chinese medicine (TCM). Based on the theory of "kidney governing reproduction" in TCM, the aim of this study was to investigate the therapeutic effects of RR-CO on DM-induced reproduction damage through regulating testicular glycolysis. Moreover, the regulation of AGEs/RAGE/HIF-1α axis on the testicular glycolysis process has also been studied. Spontaneous DM model KK-Ay mice were used to investigate the protective effect of RR, CO, RR-CO on DM-induced reproductive disturbances. RR, CO, RR-CO improved DM-induced renal and testicular morphology damages. Moreover, the impaired spermatogenesis, germ cell apoptosis and motility in testis induced upon DM were also attenuated by RR, CO or RR-CO, accompanied by an increased level of glycolysis metabolomics such as l-lactate, d-Fructose 1,6-bisphosphate, etc. Meanwhile, glucose membrane transporters (GLUT1, GLUT3), monocarboxylate transporter 4 (MCT4) expression, lactate dehydrogenase (LDH) activity, HIF-1α were upregulated by RR, CO and RR-CO treatment compared with the model group, whereas AGE level and RAGE expression were decreased with the drug administration. The RR-CO group was associated with superior protective effects in comparison to RR, CO use only. Aminoguanidine (Ami) and FPS-ZM1, the AGEs and RAGE inhibitors, were used as a tool drug to study the mechanism, showing different degrees of protection against DM-induced reproductive damage. This work preliminarily sheds light on the herb pair RR-CO exhibited favorable effects against DM-induced reproductive disturbances through enhancing testicular glycolysis, which might be mediated by AGEs/RAGE/HIF-1α axis.

Catalpol ameliorates diabetes-induced testicular injury and modulates gut microbiota.

AIMS: To explore the mechanisms of diabetes mellitus (DM)-induced testicular injury caused by modulation of testicular glycolysis and gut microbiota (GM), and evaluation of the efficacy of catalpol in reversing testicular morbidity. MAIN METHODS: A model of DM-induced testicular injury was established using a high-fat diet in KK-Ay mice. Microbial communities in the feces of mice in normal, model and catalpol (Cat) groups were analyzed by 16S gene sequencing. Correlations between the GM and lactate metabolism levels, lactate dehydrogenase activity, and indicators of testicular injury were analyzed. KEY FINDINGS: Cat significantly reduced general indicators of diabetes in mice with DM-induced reproductive injury, mitigated damage to the testicular tissue, and increased sperm count and motility. Additionally, the levels of products of glycolysis metabolism (e.g. lactate) increased following Cat treatment compared with the Model group. Disorders in the GM were also reversed in the Cat group. SIGNIFICANCE: Cat ameliorated DM-induced testicular injury in KK-Ay mice by increasing the energy available to germ cells through glycolysis, principally through modulation of the GM and a reduction in the quantities of associated pathogenic bacteria.

Loganin alleviates macrophage infiltration and activation by inhibiting the MCP-1/CCR2 axis in diabetic nephropathy.

BACKGROUND/AIMS: The theory of inflammation is one of the important theories in the pathogenesis of diabetic nephropathy (DN). We herein aimed to explore whether loganin affected macrophage infiltration and activation upon diabetic nephropathy (DN) by a spontaneous DN mice and a co-culture system of glomerular mesangial cells (GMCs) and macrophage cells (RAW264.7) which was induced by advanced glycation end products (AGEs). METHODS AND KEY FINDINGS: Loganin showed remarkable capacity on protecting renal from damage by mitigating diabetic symptoms, improving the histomorphology of the kidney, decreasing the expression of extracellular matrix such as FN, COL-IV and TGF-ß, reversing the production of IL-12 and IL-10 and decreasing the number of infiltrating macrophages in the kidney. Moreover, loganin showed markedly effects by suppressing iNOS and CD16/32 expressions (M1 markers), increasing Arg-1 and CD206 expressions (M2 markers), which were the phenotypic transformation of macrophage. These effects may be attributed to the inhibition of the receptor for AGEs (RAGE) /monocyte chemotactic protein-1 (MCP-1)/CC chemokine receptor 2 (CCR2) signaling pathway, with significantly down-regulated expressions of RAGE, MCP-1 and CCR2 by loganin. Loganin further decreased MCP-1 secretion when RAGE was silenced, which means other target was involved in regulating the MCP-1 expression. While loganin combinated with the inhibitor of CCR2 exerted stronger anti-inhibition effects of iNOS expression, suggesting that CCR2 was the target of loganin in regulating the activation of macrophages. SIGNIFICANCE: Loganin could ameliorate DN kidney damage by inhibiting macrophage infiltration and activation via the MCP-1/CCR2 signaling pathway in DN.

Radix Rehmanniae and Corni Fructus against Diabetic Nephropathy via AGE-RAGE Signaling Pathway.

BACKGROUND AND AIMS: Radix Rehmanniae and Corni Fructus (RC) have been widely applied to treat diabetic nephropathy (DN) for centuries. But the mechanism of how RC plays the therapeutic role against DN is unclear as yet. METHODS: The information about RC was obtained from a public database. The active compounds of RC were screened by oral bioavailability (OB) and drug-likeness (DL). Gene ontology (GO) analysis was performed to realize the key targets of RC, and an active compound-potential target network was created. The therapeutic effects of RC active compounds and their key signal pathways were preliminarily probed via network pharmacology analysis and animal experiments. RESULTS: In this study, 29 active compounds from RC and 64 key targets related to DN were collected using the network pharmacology method. The pathway enrichment analysis showed that RC regulated advanced glycosylation end product (AGE-) RAGE and IL-17 signaling pathways to treat DN. The animal experiments revealed that RC significantly improved metabolic parameters, inflammation renal structure, and function to protect the kidney against DN. CONCLUSIONS: The results revealed the relationship between multicomponents and multitargets of RC. The administratiom of RC might remit the DM-induced renal damage through the AGE-RAGE signaling pathway to improve metabolic parameters and protect renal structure and function.

Study on the inhibitive effect of Catalpol on diabetic nephropathy.

AIMS: Catalpol (Cat) can ameliorate oxide stress and inflammation caused by diabetic nephropathy (DN), but the molecular mechanisms are unclear. This study was designed to investigate the anti-diabetic effects of Cat and its potential mechanism. MAIN METHODS: We constructed high-fat diet/streptozotocin (HFD/STZ)-induced DN mice and high glucose (HG)-induced podocyte model. The hypoglycemic effect of Cat was analyzed by general features of DN mice. Kidney function was detected via ELISA assay and Western blotting. Renal histopathology analysis was conducted via hematoxylin and eosin (H&E), Masson and periodic acid-silver metheramine (PASM) staining. Cellular viability was measured by TUNEL assay. In order to further study the potential mechanisms of Cat, various proteins in AMPK/SIRT1/NF-κB pathway were detected in DN mice and podocytes with siRNA-AMPK intervention using Western blotting, respectively. KEY FINDINGS: We found hyperglycemia, renal structural and function abnormalities, and increased renal inflammation in DN mice. However, Cat effectively attenuated kidney damage caused by inflammation and increased AMPK, p-AMPK and SIRT1 levels. After AMPK-siRNA transfected into HG-induced podocyte model, AMPK, p-AMPK and SIRT1 levels were obviously decreased, while Cat reversed these chandes. The levels of p-NF-κB, ASC, Cleaved IL-1ß, NLRP3, Cleaved caspase1 and GSDMD-N significantly decreased by Cat treatment both in DN mice and podocyte model, which indicated that Cat could activate AMPK/SIRT1/NF-κB pathway. SIGNIFICANCE: Cat could effectively inhibit oxide stress and inflammation accompanied with pyroptosis and its mechanism might be related to AMPK/SIRT1/NF-κB pathway, indicating that Cat possessed potential value in the treatment of DN.