Melatonin decreases GSDME mediated mesothelial cell pyroptosis and prevents peritoneal fibrosis and ultrafiltration failure.

Peritoneal fibrosis together with increased capillaries is the primary cause of peritoneal dialysis failure. Mesothelial cell loss is an initiating event for peritoneal fibrosis. We find that the elevated glucose concentrations in peritoneal dialysate drive mesothelial cell pyroptosis in a manner dependent on caspase-3 and Gasdermin E, driving downstream inflammatory responses, including the activation of macrophages. Moreover, pyroptosis is associated with elevated vascular endothelial growth factor A and C, two key factors in vascular angiogenesis and lymphatic vessel formation. GSDME deficiency mice are protected from high glucose induced peritoneal fibrosis and ultrafiltration failure. Application of melatonin abrogates mesothelial cell pyroptosis through a MT1R-mediated action, and successfully reduces peritoneal fibrosis and angiogenesis in an animal model while preserving dialysis efficacy. Mechanistically, melatonin treatment maintains mitochondrial integrity in mesothelial cells, meanwhile activating mTOR signaling through an increase in the glycolysis product dihydroxyacetone phosphate. These effects together with quenching free radicals by melatonin help mesothelial cells maintain a relatively stable internal environment in the face of high-glucose stress. Thus, Melatonin treatment holds some promise in preserving mesothelium integrity and in decreasing angiogenesis to protect peritoneum function in patients undergoing peritoneal dialysis.

Recent advances in exosome-based immunotherapy applied to cancer.

Cancer stands as a prominent contributor to global mortality rates, necessitating immediate attention toward the exploration of its treatment options. Extracellular vesicles have been investigated as a potential cancer therapy in recent years. Among them, exosomes, as cell-derived nanovesicles with functions such as immunogenicity and molecular transfer, offer new possibilities for immunotherapy of cancer. However, multiple studies have shown that exosomes of different cellular origins have different therapeutic effects. The immunomodulatory effects of exosomes include but are not limited to inhibiting or promoting the onset of immune responses, regulating the function of molecular signaling pathways, and serving as carriers of antitumor drugs. Therefore, this mini-review attempts to summarize and evaluate the development of strategies for using exosomes to package exogenous cargos to promote immunotherapy in cancer.

A novel long noncoding RNA AC125257.1 facilitates colorectal cancer progression by targeting miR-133a-3p/CASC5 axis.

Colorectal cancer (CRC) is a common malignant gastrointestinal tumor. Long noncoding RNAs (lncRNAs) are revealed to be critically involved in CRC progression, providing new direction for exploring the pathogenesis of CRC. This study aimed to explore the biological functions and regulatory mechanisms of lncRNA AC125257.1 in CRC. Western blotting and reverse-transcription quantitative polymerase chain reaction were used for the measurement of gene expression. Cell counting kit-8 assay and flow cytometry analysis were used to explore the effects of AC125257.1 on CRC cell viability and apoptosis. RNA pull-down and immunoprecipitation assays were performed for validating the binding between AC125257.1 and its potential downstream microRNA. Results showed that lncRNA AC125257.1 expression was upregulated in CRC cells and tumor tissues. AC125257.1 enhanced cell viability and suppressed apoptosis of CRC cells. Moreover, the knockdown of AC125257.1 suppressed CRC progression in vitro and inhibited tumor growth in vivo. miR-133a-3p was revealed to bind with AC125257.1 in CRC cells. CASC5 was proved to be targeted by miR-133a-3p. Moreover, rescue assays indicated that the knockdown of AC125257.1 suppressed the pathogenic overexpression of CASC5. To conclude, AC125257.1 aggravates CRC development via miR-873-5p/CASC5 axis. Our findings might suggest a novel perspective that AC125257.1 may become the target for CRC treatment.

20-Hydroxyecdysone inhibits inflammation via SIRT6-mediated NF-κB signaling in endothelial cells.

20-Hydroxyecdysone (20E) is known to have numerous pharmacological activities and can be used to treat diabetes and cardiovascular diseases. However, the protective effects of 20E against endothelial dysfunction and its targets remain unclear. In the present study, we revealed that 20E treatment could modulate the release of the endothelium-derived vasomotor factors NO, PGI2 and ET-1 and suppress the expression of ACE in TNF-α-induced 3D-cultured HUVECs. In addition, 20E suppressed the expression of CD40 and promoted the expression of SIRT6 in TNF-α-induced 3D-cultured HUVECs. The cellular thermal shift assay (CETSA), drug affinity responsive target stability (DARTS) and molecular docking results demonstrated that 20E binding increased SIRT6 stability, indicating that 20E directly bound to SIRT6 in HUVECs. Further investigation of the underlying mechanism showed that 20E could upregulate SIRT6 levels and that SIRT6 knockdown abolished the regulatory effect of 20E on CD40 in TNF-α-induced HUVECs, while SIRT6 overexpression further improved the effect of 20E. Moreover, we found that 20E could reduce the acetylation of NF-κB p65 (K310) through SIRT6, but the catalytic inactive mutant SIRT6 (H133Y) did not promote the deacetylation of NF-κB p65, suggesting that the inhibitory effect of 20E on NF-κB p65 was dependent on SIRT6 deacetylase activity. Additionally, our results indicated that 20E inhibited NF-κB via SIRT6, and the expression of CD40 was increased in HUVECs treated with SIRT6 siRNA and NF-κB inhibitor. In conclusion, the present study demonstrates that 20E exerts its effect through SIRT6-mediated deacetylation of NF-κB p65 (K310) to inhibit CD40 expression in ECs, and 20E may have therapeutic potential for the treatment of cardiovascular diseases.

Cytokine-Like Protein 1 (CYTL1) as a Key Target of M-Stage Immune Infiltration in Stomach Adenocarcinoma.

Background: Stomach adenocarcinoma (STAD) has an extremely high fatality rate worldwide, and survival after metastasis is extremely poor. Cytokine-like protein 1 (CYTL1) has prognostic significance in various tumors. We aimed to explore the impact and underlying molecular mechanisms of CYTL1 in STAD through bioinformatics analysis. Methods: We used R software to analyze CYTL1 expression in STAD samples (n = 375) and normal samples (n = 32) in The Cancer Genome Atlas database. Kaplan-Meier analysis was used to verify the relationship between CYTL1 expression and overall survival (OS) and disease-specific survival (DSS) based on the clinical characteristics and subgroups of patients with STAD. Furthermore, univariate and multivariate Cox regression analyses were used to verify the outcome variables of OS and DSS in patients with STAD. Receiver operating characteristic curves were used to test the predictive power of CYTL1. The biological functions and signaling pathways of CYTL1 were determined using gene set enrichment analysis (GSEA), and the immune infiltration patterns of CYTL1 and correlation of immune-related markers were analyzed using single-sample GSEA (ssGSEA) and an estimate algorithm. Results: In our research, low CYTL1 expression (tumor vs. normal) was noted in patients with STAD. High CYTL1 expression was detrimental to OS and DSS and had good diagnostic performance (AUC = 0.731). In the subtype analysis of STAD, T3 and T4 stages, N0 and N1 stages, M0 stage, gender (female), and age (≤65 years) showed different performances between OS and DSS. Univariate and multivariate Cox analyses identified CYTL1 as an independent factor, and logistic regression analysis indicated that CYTL1 was associated with M stage (OR = 3.406) and sex (OR = 1.535). GSEA of the differential genes of CYTL1 showed the possible involvement of immunity. ssGSEA and estimation algorithms were used to further evaluate whether immune cells were closely related to CYTL1 expression, and many markers of immune cells also had statistical significance with the expression of CYTL1. Conclusion: CYTL1 may, thus, act as an independent prognostic factor for STAD and regulate STAD progression by affecting the immune microenvironment.

Isoliquiritigenin from licorice flavonoids attenuates NLRP3-mediated pyroptosis by SIRT6 in vascular endothelial cells.

ETHNOPHARMACOLOGIC RELEVANCE: Licorice is a traditional Chinese medicine that has been used for cardiovascular diseases. Recent studies found that supplementation with licorice extracts attenuated the development of atherosclerosis (AS) in hypercholesterolemic patients. Many studies have shown that licorice flavonoids, the main active components of licorice, have a variety of pharmacological effects, including anti-inflammation, regulation of lipid metabolism, and antioxidation. However, the key active components against AS in licorice flavonoids are still unclear. AIM OF THE STUDY: The aim of this paper is to investigate the active components of licorice flavonoids that exert anti-atherosclerotic effects and the underlying mechanisms. MATERIALS AND METHODS: Network pharmacology was used to screen the active components of licorice flavonoids that have anti-atherosclerotic effects. Combining bioinformatics analysis and in vitro studies, the effects and underlying mechanisms of the active component isoliquiritigenin (ISL) on cell pyroptosis were further investigated in tumor necrosis factor (TNF)-α-treated human umbilical vein endothelial cells (HUVECs). RESULTS: We constructed a compound-target network and screened 3 active components, namely, ISL, glabridin, and naringenin in licorice flavonoids. The half maximal effective concentration values of these 3 components suggested that ISL was the key active component against TNF-α-induced endothelial cell injury. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that ISL could potentially treat AS via the nucleotide-binding and oligomerization domain (NOD)-like receptor signaling pathway. An in vitro study verified that ISL suppressed TNF-α-induced NLRP3 activation and pyroptosis in HUVECs. The molecular docking and cellular thermal shift assay showed good compatibility between ISL and class III histone deacetylase sirtuin 6 (SIRT6). Moreover, we found that ISL upregulated the expression of SIRT6 in TNF-α-treated HUVECs. Further study found that SIRT6 knockdown reduced the inhibitory effect of ISL on pyroptosis, whereas the NLRP3 inhibitor reversed this process in TNF-α-treated HUVECs. CONCLUSIONS: Our results demonstrate that ISL is a key active component of licorice flavonoids. ISL attenuates NLRP3-mediated vascular endothelial cell pyroptosis via SIRT6, and SIRT6 may be a potential target of ISL for the treatment of AS.

LINC00339 accelerates invasion and migration of colorectal cancer via mediating miRNA-30a-5p.

To analyze the biological function of LINC00339 in the progression of colorectal cancer (CRC). We aim to provide directions in the early-stage treatment of CRC. LINC00339 level in 60 paired CRC tissues and paracancerous tissues was examined by quantitative real-time polymerase chain reaction (qRT-PCR). The correlation between the LINC00339 level and clinical parameters was analyzed. Moreover, the LINC00339 level in CRC cell lines was determined as well. LINC00339 expression was changed in HCT-8 and HCT-116 cell lines by transfection of LINC00339 overexpression plasmid or anti-LINC00339. The regulatory effects of LINC00339 on the migratory and invasive abilities of CRC cells were evaluated through a series of functional experiments. Dual-luciferase reporter gene assay and rescue experiments were conducted to verify the interaction of LINC00339 and miRNA-30a-5p in mediating the progression of CRC. LINC00339 was upregulated in CRC tissues relative to paracancerous tissues. CRC patients with higher levels of LINC00339 had higher rates of lymph node metastasis and distant metastasis, and worse prognosis than those with lower levels. Knockdown of LINC00339 attenuated migratory and invasive abilities of HCT-116 cells. Overexpression of LINC00339 in HCT-8 obtained the opposite trends. In addition, we verified a negative correlation between LINC00339 and miRNA-30a-5p in CRC tissues. LINC00339 served as a ceRNA to absorb miRNA-30a-5p. Rescue experiments confirmed that miRNA-30a-5p knockdown revered the regulatory effects of LINC00339 on the migratory and invasive abilities of CRC cells. LINC00339 was closely correlated to metastasis and poor prognosis of CRC. It accelerates CRC cells to migrate and invade via mediating miRNA-30a-5p.

Lipidomics of cyclophosphamide 4-hydroxylation in patients receiving post-transplant cyclophosphamide.

Biomarker-guided dosing may improve the efficacy and toxicity of cyclophosphamide (CY); however, clinical studies evaluating their association with the area under the plasma concentration-time curve (AUC) of CY and its metabolites are time- and resource-intensive. Therefore, we sought to identify lipidomic biomarkers associated with the time-varying differences in CY formation clearance to 4-hydroxycyclophosphamide (4HCY), the principal precursor to CY's cytotoxic metabolite. Hematopoietic cell transplant (HCT) patients receiving post-transplant CY (PT-CY) were enrolled, cohort 1 (n = 25) and cohort 2 (n = 26) donating longitudinal blood samples before they started HCT (pre-HCT), before infusion of the donor allograft (pre-graft), before the first dose of PT-CY (pre-CY) and 24 h after the first dose of PT-CY (24-h post-CY) which is also immediately before the second dose of CY. A total of 409 and 387 lipids were quantitated in the two cohorts, respectively. Associations between lipids, individually and at a class level, and the ratio of 4HCY/CY AUC (i.e., 4HCY formation clearance) were evaluated using linear regression with a false discovery rate <0.05. There were no individual lipids that passed control for false discovery at any time point. These results demonstrate the feasibility of lipidomics, but future studies in larger samples with multiple omic tools are warranted to optimize CY dosing in HCT.

Sirt6 inhibits vascular endothelial cell pyroptosis by regulation of the Lin28b/let-7 pathway in atherosclerosis.

Our previous study showed that Sirtuin 6 (Sirt6) plays an important role in the regulation of vascular endothelial cell inflammation. Recently, studies have reported that the RNA binding protein Lin28b directly regulates the let-7 microRNA (miRNA), which participates in the process of atherosclerosis (AS) by regulating inflammation. Pyroptosis is a form of programmed cell death that is accompanied by inflammation and is critical for AS. Thus, this study aimed to investigate the role of Sirt6 and Lin28b in vascular endothelial cell pyroptosis and the related mechanism. The present study showed that Lin28b expression was upregulated in the aortic intima and aorta of apolipoprotein E knockout (ApoE-/-) mice fed with a high-fat diet (HFD) for 8 or 12 weeks. Then, in vitro study found Lin28b was involved in tumor necrosis factor-α (TNF-α)-induced vascular endothelial cell pyroptosis, as indicated by the increased number of PI-positive cells and gasdermin D (GSDMD) cleavage, as well as the increased release of lactate dehydrogenase (LDH) and interleukin (IL)-1ß. Further studies demonstrated that TNF-α significantly decreased the expression of let-7, while Lin28b knockdown significantly increased the expression of let-7a, let-7d and let-7g. In addition, Sirt6 overexpression decreased Lin28b expression. Moreover, Sirt6 overexpression suppressed pyroptosis by decreasing the number of PI-positive cells and GSDMD cleavage, as well as by decreasing the release of LDH and IL-1ß in TNF-α-induced vascular endothelial cells. Further mechanistic studies revealed that Sirt6 directly interacted with and deacetylated Lin28b. Taken together, these findings indicate that Sirt6 inhibits vascular endothelial cell pyroptosis by negatively regulating the Lin28b/let-7 pathway in AS.

Rhaponticum carthamoides improved energy metabolism and oxidative stress through the SIRT6/Nrf2 pathway to ameliorate myocardial injury.

BACKGROUND: Rhaponticum carthamoides (Willd.) Iljin (Rha) is a member of the family Compositae that is widely used in folk medicine as a dietary supplement to treat cardiovascular diseases (CVDs), such as senile cardiac insufficiency, and to restore myocardial function after surgery. Sirtuin 6 (SIRT6), an NAD+-dependent class III histone deacetylase, plays a considerable role in the administration of CVDs. However, the specific effects and mechanism of Rha on myocardial injury remain unknown. PURPOSE: This study aimed to explore the therapeutic potential of Rha against myocardial injury as well as its underlying mechanisms in vivo and in vitro. METHODS: A myocardial ischaemia model was established in male SD rats by subcutaneously injecting ISO. The rats were gavaged with Rha (40, 80, 160 mg/kg) or Rho (6 ml/kg) for 14 successive days and then injected subcutaneously with ISO or saline solution on the 13th and 14th days. The positive effects of Rha against myocardial injury in rats were evaluated by ECG assessment, BP measurements, H&E staining, and myocardial enzyme detection. Biochemical indicators of energy metabolism and oxidative stress, such as NAD+/NADH, ATP, and MDA, were analysed by assay kits to assess the effects of Rha. The protein and mRNA expression levels of SIRT6 and Nrf2 in the myocardium were determined by western blotting and real-time PCR. RESULTS: Our results showed that Rha ameliorated myocardial ischaemia and inhibited energy metabolism disorders (NAD+/NADH ratio, ATP, and LD) and oxidative stress (SOD, ROS, etc.) in rat myocardial tissue and H9c2 cells. In addition, Rha upregulated SIRT6 and Nrf2 expression in myocardial injury. Mechanistic studies then found that SIRT6 knockdown reduced the expression of Nrf2 as well as the effects of Rha on the levels of ATP, LD, and ROS, whereas activation of Nrf2 improved the effects of Rha in cells. In summary, Rha might exert its cardioprotective effects via the SIRT6-mediated Nrf2 signaling pathway. CONCLUSION: The results suggest that Rha regulates energy metabolism and oxidative stress through the SIRT6/Nrf2 signaling pathway to play a protective role in myocardial injury.

Erratum: Vitexin Inhibits Gastric Cancer Growth and Metastasis through HMGB1-mediated Inactivation of the PI3K/AKT/mTOR/HIF-1α Signaling Pathway.

This corrects the article on p. 439 in vol. 21, PMID: 35079445.

HDAC11 promotes both NLRP3/caspase-1/GSDMD and caspase-3/GSDME pathways causing pyroptosis via ERG in vascular endothelial cells.

Histone deacetylase 11 (HDAC11), a sole member of the class IV HDAC subfamily, participates in various cardiovascular diseases. Recent evidence showed that pyroptosis was a form of inflammatory programmed cell death and is critical for atherosclerosis (AS). However, little is known about the effect of HDAC11 on endothelial cell pyroptosis in AS. Thus, this study aims to investigate the role of HDAC11 in vascular endothelial cell pyroptosis and its molecular mechanism. Firstly, we found that HDAC11 expression was up-regulated and pyroptosis occurred in the aorta of ApoE-/- mice fed with a high-fat diet (HFD) for 8 or 12 weeks. Then, in vitro study found the treatment of human umbilical vein endothelial cells (HUVECs) with tumor necrosis factor-α (TNF-α) resulted in pyroptosis, as evidenced by activation of caspase-1 and caspase-3 activation, cleavage of downstream gasdermin D (GSDMD) and gasdermin E (GSDME/DFNA5), the release of pro-inflammatory cytokines interleukin (IL)-1ß, IL-6 and IL-18, as well as elevation of LDH activity and increase of propidium iodide (PI)-positive cells. Besides, TNF-α increased HDAC11 expression and induced pyroptosis via TNFR1 in HUVECs. HDAC11 knockdown mitigated pyroptosis by suppressing both NLRP3/caspase-1/GSDMD and caspase-3/GSDME pathways in TNF-α-induced HUVECs. Moreover, GSDME knockdown by siRNA significantly decreased pyroptosis and inflammatory response, while treatment with disulfiram or necrosulfonamide (NSA) further augmented the inhibitory effects of GSDME siRNA on pyroptosis and inflammatory response. Further studies found HDAC11 formed a complex with ERG and decreased the acetylation levels of ERG. More importantly, ERG knockdown augmented vascular endothelial cell pyroptosis in TNF-α-induced HUVECs. Taken together, our study suggests that HDAC11 might promote both NLRP3/caspase-1/GSDMD and caspase-3/GSDME pathways leading to pyroptosis via regulation of ERG acetylation in HUVECs. Modulation of HDAC11 may serve as a potential target for therapeutic strategies of AS.

Effect of Shixiao San on inflammatory factors and pain in rats with endometriosis.

ETHNOPHARMACOLOGICAL RELEVANCE: In the practice of traditional Chinese medicine, endometriosis is believed to be caused by blood stasis and is characterised by dysmenorrhea, which is difficult to control. Shixiao San (SXS) has a long history of use in the treatment of gynaecological diseases. The prescriptions composed of SXS include Typhae Pollen and Faeces Trogopterori, both of which have anti-inflammatory activity. In addition, Typhae Pollen can be used to treat many kinds of blood stasis diseases. AIM OF THE STUDY: The purpose of the present study was to investigate the effect of SXS on pain relief in rats with endometriosis and to preliminarily explore its mechanism of action in alleviating pain. MATERIAL AND METHODS: Ten rats received sham operation as the Sham group, and 30 endometriosis model rats were randomly divided into three groups: the Model, Shixiao San-Low (SXS-L), and Shixiao San-High (SXS-H) groups. The rats were administered the appropriate treatment via intragastric gavage for 4 weeks. The thermal radiation pain and mechanical pain thresholds of the rats were measured every 7 days after treatment. Finally, the distribution density of nerve fibres in endometrial tissue, the inflammatory infiltration of the dorsal root ganglion (DRG), the expression of TRPV1 in the DRG, and the expression of IL-1ß, TNF-α, and IL-6 in ectopic tissue were measured. RESULTS: After SXS treatment, the growth of ectopic tissue in rats with endometriosis was significantly suppressed, their thermal radiation pain and mechanical pain thresholds increased, the density of nerve fibres and the expression of inflammatory factors in ectopic tissues reduced, and inflammatory cells infiltration in the DRG of the animals alleviated. Meanwhile, the expression of TRPV1 in the DRG was downregulated in rats with endometriosis. CONCLUSIONS: SXS could possibly inhibit the development of endometriosis and relieve pain in patients with endometriosis by reducing inflammatory responses in ectopic tissue and the DRG.

SIRT6 inhibits endothelial-to-mesenchymal transition through attenuating the vascular endothelial inflammatory response.

Endothelial-to-mesenchymal transition (EndMT) is a process of transdifferentiation in which endothelial cells gradually adopt the phenotypic characteristics of mesenchymal cells. Emerging studies demonstrate the importance of EndMT in endothelial dysfunction during inflammation. Sirtuin 6 (SIRT6), a member of the mammalian NAD+-dependent deacetylase sirtuin family, plays a critical role in cardiovascular diseases by regulating the inflammatory response. However, little is known about the effect of SIRT6 on EndMT during vascular inflammation. Therefore, we aimed to investigate the effect of SIRT6 on EndMT in endothelium-specific SIRT6 knockout (ecSIRT6-/-) mice and human umbilical vein endothelial cells (HUVECs) stimulated with inflammatory cytokines. First, we found that TNF-α and IL-1ß co-treatment induced EndMT and down-regulated SIRT6 expression in HUVECs. Adenovirus-mediated SIRT6 overexpression suppressed inflammation-induced EndMT in HUVECs. In contrast, SIRT6 knockdown further promoted EndMT. Our findings also revealed that SIRT6 attenuated the inflammatory response of HUVECs. Additionally, vascular inflammation was induced by carotid artery ligation in ecSIRT6-/- mice. Results showed that the intima of ligated carotid arteries in ecSIRT6-/- mice was significantly thickened compared to that in ecSIRT6+/+ ligated mice. Moreover, endothelium-specific SIRT6 knockout promoted EndMT and increased the expression of proinflammatory cytokines in the carotid arteries of mice. These results suggest that SIRT6 inhibits EndMT through attenuating the vascular endothelial inflammatory response. These findings may have significance for reducing the occurrence of EndMT and ameliorating certain aspects of vascular inflammation.

SIRT6 inhibits inflammatory response through regulation of NRF2 in vascular endothelial cells.

Emerging evidence suggests that inflammation plays a pivotal role in Atherosclerosis. Sirtuin 6 (SIRT6), a member of NAD+-dependent protein lysine deacylases of the sirtuin family, plays an important role in the regulation of metabolism, aging and stress resistance. However, the role of SIRT6 in vascular inflammation and its molecular mechanism is unknown. The present study showed that TNF-α significantly reduced the expression of SIRT6 protein and mRNA in a concentration- and time-dependent manner and increased the expression of monocyte chemotactic protein 1 (MCP-1), interleukin (IL) -6 and IL-1ß in human umbilical vein endothelial cells (HUVECs). Overexpression of SIRT6 but not its catalytically inactive mutant inhibited TNF-α-induced expression of MCP-1, IL-6 and IL-1ß. Knockdown of SIRT6 significantly enhanced TNF-α-induced expression of MCP-1, IL-6 and IL-1ß. Moreover, knockdown of SIRT6 reduced TNF-α-induced nuclear factor erythroid 2 related factor 2 (NRF2) nucleus protein expression, whereas knockdown of NRF2 significantly enhanced TNF-α-induced expression of MCP-1, IL-6 and IL-1ß. In addition, overexpression of SIRT6 increased NRF2 and its target genes expression, and knockdown of SIRT6 decreased NRF2 and its target genes expression. Meanwhile, knockdown of SIRT6 inhibited NRF2 nucleus protein expression. Further, knockdown of SIRT6 decreased phosphorylation of NRF2, overexpression of SIRT6 increased phosphorylation of NRF2. SIRT6 interacted with NRF2. In vivo, the levels of TNF-α and IL-1ß were increased in the serum of hyperlipidemia mice. Hyperlipidemia-induced production of MCP-1, IL-6 and IL-1ß was significantly augmented in the endothelium specific SIRT6 knockout mice. In contrast, the expression of NRF2 and its target genes was reduced. Taken together, these results indicate that SIRT6 protects against vascular inflammation via its deacetylase activity and the NRF2-dependent signaling pathway.

Hydroxytyrosol Acetate Inhibits Vascular Endothelial Cell Pyroptosis via the HDAC11 Signaling Pathway in Atherosclerosis.

Hydroxytyrosol acetate (HT-AC), a natural polyphenolic compound in olive oil, exerts an anti-inflammatory effect in cardiovascular diseases (CVDs). Pyroptosis is a newly discovered form of programmed inflammatory cell death and is suggested to be involved in the atherosclerosis (AS) process. However, the effect of HT-AC on vascular endothelial cell pyroptosis remains unknown. Thus, we aimed to investigate the effect of HT-AC on vascular endothelial cell pyroptosis in AS and related signaling pathways. In vivo studies showed that HT-AC alleviated the formation of atherosclerotic lesions and inhibited pyroptosis in the aortic intima of ApoE-/- mice fed a high-fat diet (HFD) for 12 weeks. In vitro, we found that HT-AC treatment of human umbilical vein endothelial cells (HUVECs) alleviated tumor necrosis factor-alpha (TNF-α)-induced pyroptosis by decreasing the number of PI positive cells, decreasing the enhanced protein expressions of activated caspase-1 and gasdermin D (GSDMD), as well as by decreasing the release of pro-inflammatory interleukin (IL)-1ß and IL-6. Besides, HT-AC down-regulated HDAC11 expression in the aortic intima of HFD-fed ApoE-/- mice and TNF-α-stimulated HUVECs. To determine the underlying mechanism of action, molecular docking and drug affinity responsive target stability (DARTS) were utilized to identify whether HDAC11 protein is a target of HT-AC. The molecular docking result showed good compatibility between HT-AC and HDAC11. DARTS study's result showed that HDAC11 protein may be a target of HT-AC. Further study demonstrated that knockdown of HDAC11 augmented the inhibition of HT-AC on pyroptosis in TNF-α-stimulated HUVECs. These findings indicate that HT-AC might prevent vascular endothelial pyroptosis through down-regulation of HDAC11 related signaling pathway in AS.

Protective effect of SIRT6 on cholesterol crystal-induced endothelial dysfunction via regulating ACE2 expression.

Sirtuins are a family of highly conserved nicotinamide adenine dinucleotide (NAD+)-dependent enzymes. Among the sirtuins, SIRT1 and SIRT6 participate in the regulation of endothelial functions and play significant roles in the physiological and pathological processes of cardiovascular diseases (CVD). Recently, our study found that minute cholesterol crystals (CC) can be endocytosed by endothelial cells and further impair endothelial functions. Since previous studies have reported that angiotensin-converting enzyme (ACE2) involves Angiotensin (Ang) II-induced inflammation in endothelial cells, this study was designed to investigate the role of SIRT1 and SIRT6 in CC-induced variation of ACE2 expression and the related mechanism between SIRT6 and ACE2. We found that ACE2 is involved in CC-induced endothelial dysfunction, which inhibits decreases in nitric oxide (NO) level and endothelial nitric oxide synthase (eNOS) activity and increases in inflammatory factors and adhesion molecules. Besides, SIRT1 and SIRT6 regulated the protein expression of ACE2 in CC-stimulated human umbilical vein endothelial cells (HUVECs). Moreover, bioinformatics analysis from the Enrichr database indicated that activating transcription factor 2 (ATF2), is highly correlated with genes that significantly upregulated after infection with the SIRT6 adenovirus vector. In CC-induced HUVECs, ACE2 expression was up-regulated in cells transfected with ATF2 siRNA. However, further mechanism studies revealed that overexpression of SIRT6 decreases the accumulation of p-ATF2 in the nucleus, but did not affect p-ATF2 expression in the cytoplasm. Taken together, these data indicated that SIRT6 regulates ACE2 might via inhibiting the accumulation of nucleus p-ATF2 in CC-induced endothelial dysfunction.

Vitexin Inhibits Gastric Cancer Growth and Metastasis through HMGB1-mediated Inactivation of the PI3K/AKT/mTOR/HIF-1α Signaling Pathway.

PURPOSE: Gastric cancer (GC) has high morbidity and mortality and is a serious threat to public health. The flavonoid compound vitexin is known to exhibit anti-tumor activity. In this study, we explored the therapeutic potential of vitexin in GC and its underlying mechanism. MATERIALS AND METHODS: The viability, migration, and invasion of GC cells were determined using MTT, scratch wound healing, and transwell assays, respectively. Target molecule expression was determined by western blotting. Tumor growth and liver metastasis were evaluated in vivo using nude mice. Protein expression in the tumor tissues was examined by immunohistochemistry. RESULTS: Vitexin inhibited GC cell viability, migration, invasion, and epithelial-mesenchymal transition (EMT) in a dose-dependent manner. Vitexin treatment led to the inactivation of phosphatidylinositol-3-kinase (PI3K)/AKT/hypoxia-inducible factor-1α (HIF-1α) pathway by repressing HMGB1 expression. Vitexin-mediated inhibition in proliferation, migration, invasion and EMT of GC cells were counteracted by hyper-activation of PI3K/AKT/HIF-1α pathway or HMGB1 overexpression. Finally, vitexin inhibited the xenograft tumor growth and liver metastasis in vivo by suppressing HMGB1 expression. CONCLUSIONS: Vitexin inhibited the malignant progression of GC in vitro and in vivo by suppressing HMGB1-mediated activation of PI3K/Akt/HIF-1α signaling pathway. Thus, vitexin may serve as a promising therapeutic agent for the treatment of GC.

MiR-26a targets EphA2 to resist intracellular Listeria monocytogenes in macrophages.

At infection sites, macrophages are sentinels that resist and destroy various pathogens, through direct phagocytosis. In macrophages, microRNAs play a variety of crucial roles, the most striking of which is the regulation of the ability of the host cell to resist infection. However, the underlying mechanisms associated with the anti-infection effects mediated by microRNAs remain largely unknown. Here, we demonstrated that miR-26a is downregulated during infection by Listeria monocytogenes (Lm). In miR-26a overexpressing mice, the Lm bacterial burden of liver and spleen decreased significantly within 72 h of infection, compared with that in control mice. Subsequently, RNA sequencing (RNA-seq) data suggested that miR-26a may attenuate the survival of Lm by targeting the Ephrin receptor tyrosine kinase A2 (EphA2). The knockdown of EphA2 in RAW264.7 macrophage cells resulted in decreased intracellular Lm burden. Taken together, these findings validate EphA2 as a target of miR-26a and provide a mechanism through which Lm may survive within macrophages by altering host miRNA expression.

Dextran Sulfate Protects Pancreatic ß-Cells, Reduces Autoimmunity, and Ameliorates Type 1 Diabetes.

A failure in self-tolerance leads to autoimmune destruction of pancreatic ß-cells and type 1 diabetes (T1D). Low-molecular-weight dextran sulfate (DS) is a sulfated semisynthetic polysaccharide with demonstrated cytoprotective and immunomodulatory properties in vitro. However, whether DS can protect pancreatic ß-cells, reduce autoimmunity, and ameliorate T1D is unknown. In this study, we report that DS, but not dextran, protects human ß-cells against cytokine-mediated cytotoxicity in vitro. DS also protects mitochondrial function and glucose-stimulated insulin secretion and reduces chemokine expression in human islets in a proinflammatory environment. Interestingly, daily treatment with DS significantly reduces diabetes incidence in prediabetic NOD mice and, most importantly, reverses diabetes in early-onset diabetic NOD mice. DS decreases ß-cell death, enhances islet heparan sulfate (HS)/HS proteoglycan expression, and preserves ß-cell mass and plasma insulin in these mice. DS administration also increases the expression of the inhibitory costimulatory molecule programmed death-1 (PD-1) in T cells, reduces interferon-γ+CD4+ and CD8+ T cells, and enhances the number of FoxP3+ cells. Collectively, these studies demonstrate that the action of one single molecule, DS, on ß-cell protection, extracellular matrix preservation, and immunomodulation can reverse diabetes in NOD mice, highlighting its therapeutic potential for the treatment of T1D.