Melatonin Mitigates Atrazine-Induced Renal Tubular Epithelial Cell Senescence by Promoting Parkin-Mediated Mitophagy

Single-Cell RNA Sequencing Analysis Reveals the Role of Macrophage-Mediated CD44-AKT-CCL2 Pathways in Renal Tubule Injury during Calcium Oxalate Crystal Formation

Oxalate-induced crystalline kidney injury is a common form of crystal nephropathy. The accumulation of calcium oxalate (CaOx) crystal could lead to renal epithelium injury and inflammation. The underlying cellular events in kidney after CaOx crystal formation are largely unknown. This study was aimed to gain a better understanding of mouse kidney function in the development of renal CaOx formation. The study utilized a mouse CaOx model to analyze the cellular response at 5 time points using single-cell RNA sequencing and investigate the interaction of different cells during renal CaOx crystal formation. Additionally, the study investigated the communication between these cells and macrophages, as well as the role of chemokines in recruiting infiltrating macrophages. RNA velocity analysis uncovered an alternative differentiation pathway for injured and S1 proximal tubule cells, which mainly communicate with macrophages through the SPP1-CD44 pair, along with the expression of proinflammatory factors and stone matrix genes during renal CaOx crystal formation. Furthermore, resident Fn1 macrophages were found to express chemokines, such as CCL2, which recruited infiltrating macrophages. The CCL2 secretion was mediated by the CD44-AKT pathway. Blocking CCL2 decreased the expression of injury markers in the kidney, including CLU, LCN2, and KIM-1, and inhibited CaOx crystal deposition. The study identified potential cell types and target genes involved in renal tubule injury in oxalate-related crystal nephropathy. The findings shed light on the cellular processes that contribute to the formation and damage caused by CaOx crystals within the kidney, which could lead to the development of potential cell types and target genes for treating this condition.

Melatonin-mediated cGAS-STING signal in senescent macrophages promote TNBC chemotherapy resistance and drive the SASP

The build-up of senescent cells in tissues is a key indicator of aging, associated with negative prognosis and therapy resistance. Despite immune dysfunction related to aging, also known as immunosenescence, is recognized as a factor in this process, the exact mechanisms are still unclear. In this study, we reported that melatonin deficiency accelerated macrophage senescence in triple-negative breast cancer, whereas melatonin could defend macrophages against senescence through the Nfatc1-Trim26-cgas-Sting pathway. Mechanistically, melatonin enhanced the nuclear translocation of Nfatc1 and elevated Trim26 transcription levels. Trim26, functioning as an E3 ligase, ubiquitinates cgas, thereby inhibiting the activation of the cgas-Sing pathway and consequently preventing cell senescence. Conversely, melatonin deficiency induced cgas-Sting pathway activation to promote macrophage aging. Our results show that melatonin inhibited macrophage senescence and improved chemotherapy responsiveness, with further enhancement when combined with the cgas inhibitor (G150). Overall, our findings indicated that melatonin protects macrophages from immunosenescence, suggesting its therapeutic potential for enhancing chemotherapy response.

Mammalian Ste20-like kinase 1 regulates AMPK to mitigate the progression of non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic steatohepatitis (NASH) progression is strongly associated with deteriorating hepatic function, primarily driven by free cholesterol (FC) accumulation-induced lipotoxicity. Emerging evidence highlights the regulatory role of mammalian Ste20-like kinase 1 (MST1) in modulating intrahepatic lipid homeostasis, suggesting its therapeutic potential for non-alcoholic fatty liver disease (NAFLD) management. This investigation seeks to elucidate the pathophysiological mechanisms through which MST1 modulates NASH progression.

METHODS

The experimental design employed two murine genetic models-wild-type (WT) controls and MST1-knockout (MST1-KO) specimens-subjected to a nutritionally modified Western diet (WD) enriched with saturated fats, simple carbohydrates, and dietary cholesterol to induce non-alcoholic steatohepatitis (NASH) pathogenesis. Lentiviral transduction techniques facilitated targeted MST1 overexpression in WT animals maintained on this dietary regimen. Parallel in vitro investigations utilized HepG2 hepatocyte cultures exposed to free fatty acid (FFA) cocktails comprising palmitic and oleic acids, coupled with CRISPR-mediated MST1 suppression and complementary gain-of-function manipulations to delineate molecular mechanisms.

RESULTS

NASH triggers hepatic sterol biosynthesis activation, resulting in pathological FC overload concurrent with MST1 transcriptional suppression. Genetic ablation of MST1 amplifies intrahepatic FC retention and potentiates histopathological inflammation, while MST1 reconstitution mitigates steatotic FC deposition and attenuates inflammatory cascades. Mechanistic profiling revealed MST1-mediated AMPKα phosphorylation at Thr172, which suppresses cholesterogenic enzyme expression via sterol regulatory element-binding transcription factor 2 (SREBP2) axis modulation. This phosphorylation cascade demonstrates dose-dependent inhibition of HMGCR activity, resolving FC-induced hepatotoxicity. Crucially, MST1 orchestrates AMPK/SREBP2 crosstalk to maintain sterol homeostasis, with knockout models exhibiting 67% elevated SREBP2 nuclear translocation compared to controls.

CONCLUSIONS

The regulatory axis involving MST1-mediated AMPK phosphorylation emerges as a promising therapeutic modality for modulating hepatic sterol metabolism. It demonstrates significant potential in arresting the progression of inflammatory cascades and extracellular matrix remodeling characteristic of NASH pathogenesis. Mechanistic studies confirm that this phosphorylation cascade effectively suppresses de novo lipogenesis while enhancing cholesterol efflux capacity, thereby establishing a dual-target strategy against both metabolic dysfunction and fibrotic transformation in preclinical models.

Metasilicate-based alkaline mineral water improves the growth performance of weaned piglets by maintaining gut-liver axis homeostasis through microbiota-mediated secondary bile acid pathway

Weaning stress causes substantial economic loss in the swine industry. Moreover, weaning-induced intestinal barrier damage and dysfunction of the gut-liver axis are associated with reduced growth performance in piglets. Metasilicate-based alkaline mineral water (AMW) has shown potential therapeutic effects on gastrointestinal disorders; however, the mechanisms involved and their overall effects on the gut-liver axis have not been explored. Here, sodium metasilicate (SMS) was used to prepare metasilicate-based AMW (basal water + 500 mg/L SMS). A total of 240 newly weaned piglets were allocated to the Control and SMS groups (6 replicate pens per group and 20 piglets per pen) for a 15-day trial period. Histopathological evaluations were conducted using hematoxylin and eosin staining. To analyze the composition of the gut microbiota, 16S rRNA PacBio SMRT Gene Full-Length Sequencing was performed. Western blotting and immunofluorescence were employed to assess protein expression levels. Our results indicated that metasilicate-based AMW effectively alleviated weaning-induced colonic or liver morphological injury and inflammatory response, as well as liver cholesterol metabolism disorders. Further analysis showed that metasilicate-based AMW promoted deoxycholic acid (DCA) biosynthesis by increasing the abundance of Lactobacillus_delbrueckii in the colon (P < 0.001). This consequently improved weaning-induced colon and liver injury and dysfunction through the DCA-secondary bile acid (SBA) receptors (SBAR)-nuclear factor-kappaB (NF-κB)/NOD-like receptor family pyrin domain-containing 3 (NLRP3) pathways. Growth performance parameters, including final body weight (P = 0.034) and average daily gain (P < 0.001), in the SMS group were significantly higher than those in the Control group. Therefore, metasilicate-based AMW maintains gut-liver axis homeostasis by regulating the microbiota-mediated SBA-SBAR pathway in piglets under weaning stress. Our research provides a new strategy for mitigating stress-induced gut-liver axis dysfunction in weaned piglets.

Rab8a Is a Key Target That Melatonin Prevents Lipid Disorder from Atrazine

Atrazine (ATZ), a widely used herbicide, disrupts mitochondrial function and lipid metabolism in the liver. Melatonin (MLT), a naturally synthesized hormone, combats mitochondrial dysfunction and alleviates lipid toxicity. However, the mechanisms behind ATZ-induced lipid metabolism toxicity and the protective effects of MLT remain unexplored. Mice were randomly assigned to four groups: control (Con), 5 mg/kg MLT, 170 mg/kg ATZ, and a cotreatment group receiving 170 mg/kg ATZ with 5 mg/kg MLT (ATZ+MLT). Additionally, we analyzed the effects of MLT and Rab8a on mRNA and proteins related to mitochondrial function and lipid metabolism disrupted by ATZ in AML12 cells. In conclusion, ATZ induced mitochondrial stress and disrupted fatty acid metabolism in mouse hepatocytes and AML12 cells. Exogenous MLT restores Rab8a levels, regulating fatty acid utilization in mitochondria and mitochondrial function. Notably, targeting Rab8a does not significantly affect mitochondrial function but prevents ATZ-induced lipid metabolism disorders in hepatocytes.