RAB13 regulates macrophage polarization in sepsis.

To select the core target (RAB13) in sepsis patients' peripheral blood and investigate its molecular functions and possible mechanisms. The peripheral blood of sepsis patients (n = 21) and healthy individuals (n = 9) within 24 h after admission were collected for RNA-seq, and differential gene screening was performed by iDEP online analysis software (P < 0.01; log2FC ≥ 2) and enrichment analysis, the potential core target RAB13 was screened out. The association between RAB13 expression and sepsis severity was explored using multiple datasets in the GEO database, and survival analysis was conducted. Subsequently, peripheral blood mononuclear cells (PBMCs) from sepsis and control groups were isolated, and 10 × single-cell sequencing was used to identify the main RAB13-expressing cell types. Finally, LPS was used to stimulate THP1 cells to construct a sepsis model to explore the function and possible mechanism of RAB13. We found that RAB13 was a potential core target, and RAB13 expression level was positively associated with sepsis severity and negatively correlated with survival based on multiple public datasets. A single-cell sequencing indicated that RAB13 is predominantly localized in monocytes. Cell experiments validated that RAB13 is highly expressed in sepsis, and the knockdown of RAB13 promotes the polarization of macrophages towards the M2 phenotype. This mechanism may be associated with the ECM-receptor interaction signaling pathway. The upregulation of RAB13 in sepsis patients promotes the polarization of M2-like macrophages and correlates positively with the severity of sepsis.

SPINK1 is a Potential Diagnostic and Prognostic Biomarker for Sepsis.

Purpose: There are no satisfactory diagnostic biomarkers for sepsis. Accordingly, this study screened biomarkers valuable for sepsis diagnosis and prognosis using data-independent acquisition (DIA) combined with clinical data analysis. Patients and Methods: Serine protease inhibitor Kazal-type 1 (SPINK1) is a differentially expressed protein that was screened using DIA and bioinformatics in sepsis patients (n = 22) and healthy controls (n = 10). The plasma SPINK1 levels were detected using an enzyme-linked immunosorbent assay (ELISA) in an expanded population (sepsis patients, n = 52; healthy controls, n = 10). The diagnostic value of SPINK1 in sepsis was evaluated using receiver operating characteristic (ROC) curve analysis based on clinical data. The prognostic value of SPINK1 for sepsis was evaluated using correlation and survival analyses. Results: DIA quality control identified 78 differential proteins (72 upregulated and six downregulated), among which SPINK1 was highly expressed in sepsis. The ELISA results suggested that SPINK1 expression was significantly elevated in the sepsis group (P < 0.05). ROC analysis of SPINK1 yielded an area under the curve (AUC) of 0.9096. Combining SPINK1 with procalcitonin (PCT) for ROC analysis yielded an AUC of 1. SPINK1 expression was positively correlated with the Sequential Organ Failure Assessment (SOFA) score (r = 3497, P = 0.0053) and APACHE II score (r = 3223, P = 0.0106). High plasma SPINK1 protein expression was negatively correlated with the 28-day survival rate of patients with sepsis (P = 0.0149). Conclusion: The plasma of sepsis patients contained increased SPINK1 protein expression. Combining SPINK1 with PCT might have a high diagnostic value for sepsis. SPINK1 was associated with the SOFA score, APACHE II score, and the 28-day survival rate in patients with sepsis.

Dietary fiber intake is associated with chronic kidney disease (CKD) progression and cardiovascular risk, but not protein nutritional status, in adults with CKD.

BACKGROUND AND OBJECTIVES: Evidence suggests that dietary fiber benefits patients with chronic kidney disease (CKD); however, this conclusion requires further validation. In this study, we examined the effects of dietary fiber on kidney function, inflammation, indoxyl sulfate, nutritional status, and cardiovascular risk in patients with advanced CKD. METHODS AND STUDY DESIGN: We performed linear regressions to assess the association between dietary fiber intake and CKD parameters. The aforementioned parameters were compared over an 18-month follow- up period. Kaplan-Meier analysis was used to investigate the association between fiber intake and Cardiac vascular disease (CVD). RESULTS: In total, 157 patients were included in this study. Dietary fiber and inflammatory indices were associated (interleukin [IL]-6: ß=-0.024, p=0.035). The differential estimated glomerular filtration rate (ΔeGFR) as well as levels of C-reactive protein, IL-6, indoxyl sulfate, and serum cholesterol in the higher fiber intake (>=25 g/day) group were lower than those in the lower fiber intake (<25 g/day) group (p<0.05). Differences in IL-6 and indoxyl sulfate levels were more significant in patients in the higher protein intake group (p<0.05). Dietary fiber intake may be a protective factor associated with CVD (hazard ratio=0.537 and 0.305- 0.947). The protein nutritional status was not different between the two groups (p>0.05). CONCLUSIONS: Our results suggest that increasing fiber intake can retard the decrease in the eGFR; can reduce the levels of proinflammatory factors, indoxyl sulfate, and serum cholesterol; and is negatively associated with cardiovascular risk, but does not disrupt the nutritional status of patients with CKD.

Astragalus polysaccharides decrease muscle wasting through Akt/mTOR, ubiquitin proteasome and autophagy signalling in 5/6 nephrectomised rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Existing evidences suggest that Radix Astragali and its polysaccharides composition (APS) can improve muscle mass, but the mechanisms need more research. AIM OF THE STUDY: In this study, we aimed to examine the effects of APS on muscle wasting at molecular level in 5/6 nephrectomised rats. MATERIALS AND METHODS: We performed 5/6 nephrectomy or sham operation in 160 6-week-old Sprague-Dawley rats, and feed animals with or without 2% APS for 155 days. After treatment, we compared the change of weight, muscle fibre, protein metabolism, pro-inflammatory factors (TNF-α, IL-15, CRP) and oxidative factors (MDA, SOD) among each group. In addition, we detected the Akt/mTOR, ubiquitin proteasome, autophagy signalling and AA transporters in vivo and in vitro. RESULTS: Data in vivo show 2% APS could alleviate weight loss and improve protein metabolism in nephrectomised rats. The levels of serum pro-inflammatory factors and oxidative factors were restored by APS treatment. In molecular levels, APS restored Akt/mTOR, MAFbx, MuRF1, Atg7, LC3B-II/LC3B-I and SLC38A2 which changed in nephrectomised rats. Data in vitro show the optimal dose of APS is 0.2mg/mL, and SLC38A2 siRNA attenuated the effects of 0.2mg/mL APS on atrophy and autophagy. CONCLUSIONS: Our results suggested APS could improve muscle wasting through Akt/mTOR, ubiquitin proteasome and autophagy signalling, and SLC38A2 may be one of potential targets.

Emodin attenuates TNF-α-induced apoptosis and autophagy in mouse C2C12 myoblasts though the phosphorylation of Akt.

Emodin, a major component of Rheum palmatum, has been reported to significantly protect neural tissue against apoptosis and autophagy. However, the effects and underlying mechanisms of action of emodin in muscle atrophy are still poorly defined. In this study, we investigated the protective effects and the underlying mechanisms by which emodin acts on tumor necrosis factor alpha (TNF-α)-induced apoptosis and autophagy in mouse C2C12 myoblasts. Emodin, at various concentrations, decreased TNF-α-induced apoptosis in C2C12 myoblasts, which were analyzed by Hoechst 33342 staining and annexin V/PI analysis. Emodin also inhibited the collapse of the mitochondrial membrane potential and the generation of reactive oxygen species in TNF-α-stimulated C2C12 myoblasts. Consistent with these results, the expression of Bcl-2 was increased, whereas the expression of Bax, cleaved-caspase 3 and cleaved-PARP was decreased after emodin treatment. These data demonstrate that emodin attenuated apoptosis in TNF-α-stimulated C2C12 myoblasts through mitochondrial signaling pathways. In addition, emodin inhibited autophagy in TNF-α-stimulated C2C12 myoblasts by suppressing the expression of LC3-II, Beclin-1 and Atg7. Emodin also resulted in the upregulation of the phosphorylated forms of Akt. Taken together, these results suggest that emodin inhibited apoptosis and autophagy in TNF-α-induced C2C12 myoblasts, possibly through the activation of phosphorylated Akt. Our findings suggest that emodin could be a potential therapeutic agent in the treatment of muscle atrophy.

Effects of Astragalus Polysaccharides on Dysfunction of Mitochondrial Dynamics Induced by Oxidative Stress.

This paper studied the chronic fatigue induced by excessive exercise and the restoration effects of Astragalus polysaccharides (APS) on mitochondria. In vivo, we found that excessive exercise could cause oxidative stress statue which led to morphological and functional changes of mitochondria. The changes, including imbalance between mitochondria fusion-fission processes, activation of mitophagy, and decrease of PGC-1α expression, could be restored by APS. We further confirmed in vitro, and what is more, we found that APS may ameliorate mitochondrial dysfunction through Sirt1 pathway. Based on the results, we may figure out part of the molecular mechanism of mitochondrial amelioration by APS.

[Shenshuai Yingyang capsule ameliorates muscle atrophy in rats with chronic renal failure: role of Wnt7a-Akt/mTOR signal pathway].

OBJECTIVE: To observe the effect of Shenshuai Yingyang Capsule (SSYYJN) in ameliorating muscle atrophy in rats with chronic renal failure (CRF) and explore the role of Wnt7a-Akt/mTOR signal pathway in mediating this effect. METHODS: Male rats were randomly assigned to 5/6 nephrectomy group and sham-operated group, and the former group was further randomly divided into CRF model group, KA group, and SSYYJN group. The size of anterior tibia muscle was examined microscopically with HE staining. Protein synthesis in the soleus muscle was investigated by (14)C-phenylalanine experiment, and the expression of Wnt7a, frizzled-7, phospho-Akt, phospho-mTOR and GAPDH were detected with Western blotting. RESULTS: The body weight, the wet and dry weight, cross-sectional area, and muscle protein synthesis of the anterior tibia muscles, and expressions of the proteins in the Wnt7a/Akt signaling pathway all increased significantly in SSYYJN and KA groups as compared with those in the model group. CONCLUSION: SSYYJN can effectively improve muscle atrophy in the rat model of CRF possibly by reversing the reduction in the expressions of Wnt7a/Akt signaling pathway proteins in the skeletal muscles.

Astragalus Polysaccharide Inhibits Autophagy and Apoptosis from Peroxide-Induced Injury in C2C12 Myoblasts.

The aim is to study the effects and underlying mechanisms of astragalus polysaccharide (APS) on the peroxide-induced injury in C2C12 myoblasts in vitro. Cell viability in the presence or absence of APS was detected by the methyl thiazolyl tetrazolium colorimetric assay. The autophagosomes were observed by electron microscopy to examine the influence of APS on autophagy caused by H2O2 in C2C12 cells, and the percentage of apoptosis cells was measured by flow cytometry. To further confirm the effect of H2O2 on C2C12 cells, the protein expression of LC3 and RARP, which are the markers of autophagy and apoptosis, respectively, was analyzed by Western blot, as well as the expression levels of p-p70S6K, p70S6K, Bcl-2, Bax, cyto-C, and Caspase-3, to reveal the underlying mechanisms. We observed multiple effects of APS on C2C12 functionality. APS treatment of C2C12 cells at 1 mg/mL reduced cell viability to less than 70 %, and analysis by electron microscopy revealed that APS also reduced the number of H2O2-induced autophagosome formation. Similarly, APS abated the H2O2-mediated increase in cell apoptosis, which was accompanied by the inhibition of LC3 II and RARP that are normally upregulated by H2O2. The expression of p-p70S6K and p70S6K, however, remained unchanged in C2C12 cells in the Control, H2O2 and H2O2 + APS groups. In addition, APS promoted the expression of protein Bcl-2 in H2O2-treated C2C12 cells, but did not change Bax, thus reducing the Bax/Bcl-2 ratio that in turn prevented the release of cytochrome c and the activation of caspase-3. APS inhibits the autophagy and apoptosis induced by peroxide injury in C2C12 myoblasts through two independent signaling pathways: the mTOR-independent pathway for the inhibition of autophagy, and the caspase-3-dependent pathway for the suppression of apoptosis.