Aquaporin 9 Represents a Novel Target of Chronic Liver Injury That May Antagonize Its Progression by Reducing Lipotoxicity

CCR2 antagonist attenuates calcium oxalate-induced kidney oxidative stress and inflammation by regulating macrophage activation

C-C chemokine receptor type 2 (CCR2) is a monocyte chemokine associated with oxidative stress and inflammation. Kidney stones (KS) are composed of calcium oxalate (CaOx), which trigger renal oxidative stress and inflammatory. This study aims to evaluate the effects of CCR2 on KS in vivo and in vitro. Eight-week-old male C57BL/6J mice were intraperitoneally injected with glyoxylate (GOX) daily to establish a KS model, and along with CCR2 antagonist (INCB3344) treatment on days 2, 4, and 6. The results showed that CCR2 antagonist reduced renal injury markers (blood urea nitrogen and serum creatinine), alleviated renal tubular injury and CaOx crystal deposition. CCR2 antagonist also decreased CCR2 expression induced by GOX treatment and increased Nrf2 expression. GOX treatment promoted malondialdehyde (MDA) production, decreased glutathione (GSH) content, and inhibited catalase (CAT) and superoxide dismutase (SOD) activity, however, CCR2 antagonist attenuated the above effects of GOX. CCR2 antagonist had inhibitory effects on GOX-induced inflammatory cytokine expression (IL1B, IL6 and MCP1), and inhibited apoptosis by increasing Bcl-2 expression and decreasing Bax and cleaved-caspase 3 expression. In vitro experiments were performed by co-culture model of CaOx-induced damaged HK-2 cells and macrophage-like THP-1 cells. CCR2 antagonist inhibited CaOx-induced THP-1 cell M1 polarization by decreasing the TNF-α, IL6 and iNOS levels, and further alleviated CaOx-induced oxidative stress damage, inflammatory response and apoptosis of HK-2 cells. The study suggests that CCR2 antagonist may be resistant to CaOx crystals-induced oxidative stress and inflammation by inhibiting macrophage M1 polarization.

Multilevel Regulation of Membrane Proteins in Response to Metal and Metalloid Stress: A Lesson from Yeast

In the face of flourishing industrialization and global trade, heavy metal and metalloid contamination of the environment is a growing concern throughout the world. The widespread presence of highly toxic compounds of arsenic, antimony, and cadmium in nature poses a particular threat to human health. Prolonged exposure to these toxins has been associated with severe human diseases, including cancer, diabetes, and neurodegenerative disorders. These toxins are known to induce analogous cellular stresses, such as DNA damage, disturbance of redox homeostasis, and proteotoxicity. To overcome these threats and improve or devise treatment methods, it is crucial to understand the mechanisms of cellular detoxification in metal and metalloid stress. Membrane proteins are key cellular components involved in the uptake, vacuolar/lysosomal sequestration, and efflux of these compounds; thus, deciphering the multilevel regulation of these proteins is of the utmost importance. In this review, we summarize data on the mechanisms of arsenic, antimony, and cadmium detoxification in the context of membrane proteome. We used yeast Saccharomyces cerevisiae as a eukaryotic model to elucidate the complex mechanisms of the production, regulation, and degradation of selected membrane transporters under metal(loid)-induced stress conditions. Additionally, we present data on orthologues membrane proteins involved in metal(loid)-associated diseases in humans.

The anti-liver fibrosis effect of Tibetan medicine (Qiwei Tiexie capsule) is related to the inhibition of NLRP3 inflammasome activation in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Qiwei Tiexie capsule (QWTX) is an improved form of a classical prescription of Tibetan medicine-Qiwei Tiexie pill. It has been employed in the treatment of a variety of chronic liver disorders, including liver fibrosis. Uncertainty still exists regarding the mechanism of QWTX action in liver fibrosis.

AIM OF THE STUDY

Confirm the anti-liver fibrosis effect of QWTX and reveal its mechanism from the perspective of NOD-like receptor protein 3 (NLRP3) inflammasome activation.

MATERIALS AND METHODS

In vivo experiment: A rat model of carbon tetrachloride -induced liver fibrosis was constructed. All rats were randomly divided into six groups: a control group, a model group, a group receiving the positive drug (Biejia Ruangan tablet), and three groups receiving QWTX at high, medium, and low doses. The contents of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin (TBil) were detected in serum. Hematoxylin and eosin staining and Masson's staining were used to assess the histomorphological alteration of the liver. The levels of glutathione peroxidase, hydroxyproline, tumor necrosis factor alpha (TNF-α), and interleukin 1 beta (IL-1β) in the liver were determined using the corresponding detection kits. Real-time polymerase chain reaction, immunofluorescence, and western blotting were used to determine the expression levels of NLRP3, adaptor protein (ASC), caspase-1, and alpha-smooth muscle actin (α-SMA). In vitro experiment: Four groups of rat hepatic stellate cell line (HSC-T6) cells were created: the control group, the low-dose QWTX group (0.05 mg/mL), the medium-dose QWTX group (0.1 mg/mL), and the high-dose QWTX group (0.2 mg/mL). Cell viability was assessed using a cell counting kit, and the amounts of collagen type I (Col I) and IL-1β in the cell lysate were measured using an enzyme-linked immunosorbent assay kit. The mRNA and protein expression of NLRP3, ASC, caspase-1, and α-SMA were also estimated.

RESULTS

QWTX had an inhibitory effect on liver fibrosis and a negative effect on HSC activation, while it improved liver histopathological injury and abnormal liver function and increased hydroxyproline content and glutathione peroxidase activity in vivo. QWTX decreased the expression of α-SMA, NLRP3, caspase-1, ASC, and IL-1β both in vitro and in vivo.

CONCLUSIONS

Tibetan medicine QWTX had a significant anti-liver fibrosis effect that was related to the inhibition of NLRP3 inflammasome activation in vivo and in vitro.

Immunolocalisation of aquaporins 3, 7, 9 and 10 in the epididymis of three wild ruminant species (Iberian ibex, mouflon and chamois) and sperm cryoresistance

CONTEXT

In the epididymis, epithelial cells manage changes in the luminal environment for proper sperm maturation. Moreover, aquaglyceroporins, a subgroup of aquaporins (AQP), modulate the transport of water, glycerol and other small molecules in epithelial cells.

AIMS

We aim to characterise the lining epithelium, quantify its cell composition and immunolocalise the aquaglyceroporins AQP3, AQP7, AQP9 and AQP10 alongside the epididymal ductus of three wild ruminant species, and to determine if species-specific differences could be associated with cauda sperm cryoresistance variations.

METHODS

Epididymides from Iberian ibex (n =5), mouflon (n =5) and chamois (n =6) were obtained. Cauda spermatozoa were collected and sperm parameters were analysed before and after freezing. Histology and immunohistochemistry of AQP3, 7, 9, 10 and T-CD3 were performed in the caput, corpus and cauda epididymal regions.

KEY RESULTS

This work first describes the lining epithelium in Iberian ibex, mouflon and chamois epididymis along the three anatomical regions, consisting of principal, basal, apical, clear and halo cells. However, the percentage of each cell type differed in ibex compared to mouflon and chamois. The positive T-CD3 immunolabeling of all the halo cells confirmed their T-lymphocyte nature. Aquaglyceroporin expression patterns were similar among species, except for differences in AQP7 and AQP10 immunolocalisation in ibex. Species-specific differences in epididymal sperm cryoresistance were confirmed.

CONCLUSIONS

The epididymal epithelium of the three wild ruminants differ in their relative number of cell types and AQP immunolocalisation, which ultimately appears to affect cauda epidydimal spermatozoa cryoresistance.

IMPLICATIONS

Our study provides information on the relevance of the quantitative composition and AQP pattern expression in epididymal lining epithelium on sperm cryoresistance.

Integrated multiomics analysis reveals changes in liver physiological function in Aqp9 gene knockout mice

Aquaporin 9 (AQP9) is the main channel by which blood glycerol enters the liver, where it plays key roles in osmotic pressure regulation and energy metabolism. Previous studies have shown that AQP9 is involved in the pathogenesis of many liver diseases. In this study, we aimed to clarify the role of AQP9 in maintaining the physiological environment of the liver using Aqp9^-/- mice. We constructed Aqp9 knockout mice and used comprehensive multiomics analysis to elucidate the potential molecular effects of AQP9 expression on liver tissue. Knockout of Aqp9 reduced mouse body weight by affecting glycerol metabolism and led to hepatocyte death and inflammatory cell infiltration, which was confirmed by transcriptomics, proteomics and metabolomics. Moreover, knockout of Aqp9 triggered immune and inflammatory responses, leading to scattered and mild liver cell pyroptosis and compensatory liver cell proliferation.

Lactobacillus plantarum J26 Alleviating Alcohol-Induced Liver Inflammation by Maintaining the Intestinal Barrier and Regulating MAPK Signaling Pathways

Alcoholic liver disease (ALD), as a global health problem, is mainly caused by liver inflammation. Meanwhile, probiotics have been considered as a potential and promising strategy to prevent and alleviate ALD. This study aimed to investigate the ameliorative effect of pre-intaking with Lactobacillus plantarum J26 (L. plantarum J26) on alcohol-induced liver inflammation, with emphasis on the underlying mechanism for alleviating ALD. The results indicated that L. plantarum J26 could reduce the abundance of Gram-negative pathogenic bacteria by regulating the gut microbiota in mice with alcoholic liver injury, thereby reducing the lipopolysaccharide (LPS) content in the intestine. In addition, L. plantarum J26 could also maintain the intestinal barrier, prevent LPS from crossing the intestinal barrier to correct disorders of the gut-liver axis and then inhibit the activation of Toll-like receptor 4 (TLR4)-mediated MAPK signaling pathway, reducing liver inflammation and restoring liver functions. In conclusion, pre-intake of L. plantarum J26 could alleviate alcohol-induced liver inflammation, which may be closely related to the role of intestinal microbiota in regulating and maintaining the intestinal barrier and then regulating the MAPK signaling pathway.

Untargeted metabolomics reveals the role of AQP9 in nonalcoholic fatty liver disease in a mice model

Previous studies have shown that AQP9 plays an important role in energy metabolism in nonalcoholic fatty liver disease (NAFLD). Recently, metabolomic analyses were used to determine the slight changes in metabolic profiles and helped to understand the disease progression, therapeutic intervention of NAFLD. A mouse model of NAFLD was established with a high-fat diet (HFD), and Aqp9 knockout mice were constructed. Untargeted metabolomics techniques were used to evaluate the potential mechanism of the effect of AQP9 in NAFLD. The results indicated that AQP9 plays a regulatory role in the occurrence of NAFLD. Moreover, a total of 220 candidate biomarkers were screened and identified. Cluster analysis and enrichment analysis of differential metabolites indicated that fatty acid biosynthesis was mainly disturbed when compared against the control group, which was mitigated by knockout of Aqp9. These results show that untargeted metabolomics help to understand the effects of AQP9 in NAFLD.

The Multifaceted Role of Aquaporin-9 in Health and Its Potential as a Clinical Biomarker

Aquaporins (AQPs) are transmembrane channels essential for water, energy, and redox homeostasis, with proven involvement in a variety of pathophysiological conditions such as edema, glaucoma, nephrogenic diabetes insipidus, oxidative stress, sepsis, cancer, and metabolic dysfunctions. The 13 AQPs present in humans are widely distributed in all body districts, drawing cell lineage-specific expression patterns closely related to cell native functions. Compelling evidence indicates that AQPs are proteins with great potential as biomarkers and targets for therapeutic intervention. Aquaporin-9 (AQP9) is the most expressed in the liver, with implications in general metabolic and redox balance due to its aquaglyceroporin and peroxiporin activities, facilitating glycerol and hydrogen peroxide (H₂O₂) diffusion across membranes. AQP9 is also expressed in other tissues, and their altered expression is described in several human diseases, such as liver injury, inflammation, cancer, infertility, and immune disorders. The present review compiles the current knowledge of AQP9 implication in diseases and highlights its potential as a new biomarker for diagnosis and prognosis in clinical medicine.

VRT-043198 Ameliorates Surgery-Induced Neurocognitive Disorders by Restoring the NGF and BNDF Expression in Aged Mice

BACKGROUND

Perioperative neurocognitive disorders (PND) are common surgical complications in the elderly. Pyroptosis-associated inflammation has been suggested to participate in a series of neurocognitive diseases, including Alzheimer's disease. Given that VRT-043198 can reportedly inhibit caspase-1-induced pyroptosis, this study sought to determine whether VRT-043198 reduced PND in a mouse model following abdominal exploratory laparotomy.

METHODS

20-month-old male C57/BL mice were used to establish an abdominal exploratory laparotomy (AEL) model of PND. VRT-043198 (1, 10 and 100 mg/kg) was administered intraperitoneally immediately after surgery. Thirty days post-surgery, the mice were evaluated in the Morris water maze test. Their number of neurons, neurotrophin nerve growth factor (NGF) levels and brain-derived neurotrophic factor (BDNF) were measured. In the hippocampus, A1-type astrocytes and M1-type microglia were assessed using an immunofluorescence assay and Western blot, respectively. Caspase-1 activity, IL-1β, IL-18, and PPAR-γ were also measured 24h after surgery.

RESULTS

VRT-043198 administration increased the time to cross the platform and increased the ratio of distance and time in the targeted quadrant after surgery. Furthermore, it was found that VRT-043198 restored neuronal amount, increased NGF and BDNF and decreased the number of A1-type astrocytes and M1-type microglia. VRT-043198 also attenuated caspase-1 activity, downregulated IL-1β and IL-18, but increased PPAR-γ 24h post-surgery.

CONCLUSION

VRT-043198 improved PND in aged mice after abdominal exploratory laparotomy by restoring the NGF and BNDF expression. These results indicate that VRT-043198 may be a potential therapy for PND.