ATP6V0d2 mediates leucine-induced mTORC1 activation and polarization of macrophages

Exploring the mechanisms of cow placental peptides in delaying liver aging based on mitochondrial energy metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Placenta is a kind of traditional Chinese medicine, known as "Ziheche". The role of cow placental peptides (CPP) in delaying liver aging has been reported, and in-depth exploration of the specific regulatory mechanisms is of great significance for the recycling and utilization of CPP and the development of natural anti-aging drugs.

AIM OF THE STUDY

To investigate the protective effects and mechanisms of CPP on liver aging induced by D-galactose (D-gal) in mice from the perspective of mitochondrial energy metabolism.

METHODS

An aging model was induced in mice using D-gal. The body weight and liver index of mice were measured, followed by staining and electron microscopy to observe liver morphology and aging markers. Reactive oxygen species (ROS) levels and antioxidant-related indicators were assessed, and mitochondrial function was evaluated. Finally, changes and mechanisms in liver transcriptomics and targeted mitochondrial energy metabolomics were analyzed and integrated to elucidate the regulatory pathways through which CPP delays liver aging.

RESULTS

CPP improved liver structural damage, oxidative stress, and mitochondrial dysfunction induced by D-galactose in aging mice. It increased the final body weight and liver index, alleviated hepatocyte swelling and degeneration, enhanced liver antioxidant capacity, and restored normal mitochondrial morphology and function. The combined analysis of targeted mitochondrial energy metabolomics and liver transcriptomics revealed that CPP directly or indirectly regulated mitochondrial energy metabolism and delayed aging by influencing the cAMP signaling pathway, PI3K-Akt signaling pathway, oxidative phosphorylation, and other pathways, thereby modulating related genes and metabolites.

Leucine alleviates cytokine storm syndrome by regulating macrophage polarization via the mTORC1/LXRα signaling pathway

Cytokine storms are associated with severe pathological damage and death in some diseases. Excessive activation of M1 macrophages and the subsequent secretion of pro-inflammatory cytokines are a major cause of cytokine storms. Therefore, promoting the polarization of M2 macrophages to restore immune balance is a promising therapeutic strategy for treating cytokine storm syndrome (CSS). This study was aimed at investigating the potential protective effects of leucine on lipopolysaccharide (LPS)-induced CSS in mice and exploring the underlying mechanisms. CSS was induced by LPS administration in mice, which were concurrently administered leucine orally. In vitro, bone marrow derived macrophages (BMDMs) were polarized to M1 and M2 phenotypes with LPS and interleukin-4 (IL-4), respectively, and treated with leucine. Leucine decreased mortality in mice treated with lethal doses of LPS. Specifically, leucine decreased M1 polarization and promoted M2 polarization, thus diminishing pro-inflammatory cytokine levels and ameliorating CSS in mice. Further studies revealed that leucine-induced macrophage polarization through the mechanistic target of rapamycin complex 1 (mTORC1)/liver X receptor α (LXRα) pathway, which synergistically enhanced the expression of the IL-4-induced M2 marker Arg1 and subsequent M2 polarization. In summary, this study revealed that leucine ameliorates CSS in LPS mice by promoting M2 polarization through the mTORC1/LXRα/Arg1 signaling pathway. Our findings indicate that a fundamental link between metabolism and immunity contributes to the resolution of inflammation and the repair of damaged tissues.

RNA sequencing and proteomic profiling reveal alterations by MPTP in chronic stomach mucosal injury in tree shrew Chinese (Tupaia belangeri chinensis)

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a neurotoxin that can cause gastrointestinal ulcers by affecting dopamine levels. Therefore, MPTP has been considered a toxic substance that causes gastric ulcer disease in experimental animals. In this study, tree shrews were used as the animal model of gastric mucosa injury, and MPTP was intraperitoneally injected at a lower MPTP dosage 2 mg/kg/day for 13 weeks, while tree shrews were not injected as the control group. Under the light microscope, local congestion or diffuse bleeding points of gastric mucosa and multiple redness and swelling bleeding symptoms on the inner wall were observed in the treatment group, as well as immune cell infiltration was found in HE staining, but no such phenomenon was observed in the control group. In order to explore the molecular basis of changes in MPTP induced gastric mucosa injury, the transcriptome and proteome data of gastric mucosa were analyzed. We observed significant differences in mRNA and protein expression levels under the influence of MPTP. The changes in mRNA and proteins are related to increased immune infiltration, cellular processes and angiogenesis. More differentially expressed genes play a role in immune function, especially the candidate genes RPL4 and ANXA1 with significant signal and core role. There are also differentially expressed genes that play a role in mucosal injury and shedding, especially candidate genes GAST and DDC with certain signaling and corresponding functions. Understanding the factors and molecular basis that affect the expression of related genes is crucial for coping with Emotionality gastric mucosa injury disease and developing new treatment methods to establish the ability to resist disease.

Growth or death? Control of cell destiny by mTOR and autophagy pathways

One of the central regulators of cell growth, proliferation, and metabolism is the mammalian target of rapamycin, mTOR, which exists in two structurally and functionally different complexes: mTORC1 and mTORC2; unlike m TORC2, mTORC1 is activated in response to the sufficiency of nutrients and is inhibited by rapamycin. mTOR complexes have critical roles not only in protein synthesis, gene transcription regulation, proliferation, tumor metabolism, but also in the regulation of the programmed cell death mechanisms such as autophagy and apoptosis. Autophagy is a conserved catabolic mechanism in which damaged molecules are recycled in response to nutrient starvation. Emerging evidence indicates that the mTOR signaling pathway is frequently activated in tumors. In addition, dysregulation of autophagy was associated with the development of a variety of human diseases, such as cancer and aging. Since mTOR can inhibit the induction of the autophagic process from the early stages of autophagosome formation to the late stage of lysosome degradation, the use of mTOR inhibitors to regulate autophagy could be considered a potential therapeutic option. The present review sheds light on the mTOR and autophagy signaling pathways and the mechanisms of regulation of mTOR-autophagy.

Regulation of the V-ATPase subunit ATP6V0D2 and its role in demyelination after peripheral nerve injury

After peripheral nerve injury, demyelinating Schwann cells discharge myelin debris and macrophages execute myelin degradation, leading to demyelination of degenerating axons, which is essential for efficient nerve regeneration. In this study, we show that vacuolar-type proton ATPase subunit d2 (Atp6v0d2) is among the most highly upregulated genes in degenerating mouse sciatic nerves after nerve injury using microarray analysis. ATP6V0D2 is mostly expressed in macrophages of injured nerves. Atp6v0d2 knockout mice display delayed peripheral nerve demyelination and significantly attenuated myelin lipid digestion after nerve injury. However, macrophage recruitment and Schwann cell dedifferentiation are unaffected by loss of Atp6v0d2 expression. Taken together, these data demonstrate that ATP6V0D2 in macrophages is specifically required for demyelination during Wallerian degeneration.

Acid external and internal environment exchange the Oreochromis niloticus tissue immune gene expression compared to the mouse macrophage polarization model

The water environment plays an important role in animal physiology. In this study, we sought to evaluate the effect of the acid environment on the Oreochromis niloticus (Nile tilapia) internal microenvironment immune response compare to the mouse macrophage model (J77A.1). The acid environment treated mouse macrophage J774A.1 model have shown that acidic treatment is able to polarize macrophages into M2-like macrophages via an increase in Ym1, Tgm2, Arg1, Fizz1, and IL-10 expression. Metabolic analysis of mouse macrophages (J774A.1) at pH 2 vs. pH 7 and pH 4 vs. pH 7 have been shown to promote the expression of intracellular acetylcholine, choline, prochlorperazine, L-leucine, and bisphenol A,2-amino-3-methylimidazo[4,5-f] quinolone metabolites in the M2-like macrophage. Immune gene expression of the O. niloticus spleen and liver treated at pH 2, 4, and 7 was shown to reduce TNF-α, IL-1 β, IL-8, and IL-12 expression compared to pH 7 treatment. Immune gene was induced in O. niloticus following culture at pH 5, 6, and 7 fresh water environment. Taken together, we found that the acid internal environment polarizes tissues into an M2 macrophage developmental microenvironment. However, if the external environment is acid, tissues are exposed to an M1 macrophage developmental microenvironment.

ATP6V0d2 Suppresses Alveoli Macrophage Alternative Polarization and Allergic Asthma via Degradation of PU.1

PURPOSE

Macrophages are important regulators of environmental allergen-induced airway inflammation and asthma. ATP6V0d2 is a subunit of vacuolar ATPase highly expressed in macrophages. However, the functions of ATP6V0d2 in the regulation of pathogenesis of allergic asthma remain unclear. The aim of this study is to determine the function and related molecular mechanisms of macrophage protein ATP6V0d2 in allergic asthma.

METHODS

We compared the disease severity between female C57BL/6 wild-type and ATP6V0d2^-/- mice in an ovalbumin (OVA)-induced asthma model. We also investigated the association of expression of ATP6V0d2, PU.1 and CCL17 with disease severity among asthmatic patients.

RESULTS

The expression of ATP6V0d2 in sputum cells of asthmatic patients and in the lungs of OVA-challenged mice was enhanced compared to healthy subjects and their counterparts, respectively. However, ATP6V0d2-deficient mice exaggerated inflammatory cell infiltration as well as enhanced alternative activated macrophage (AAM) polarization and mucus production in an OVA-induced asthma model. Furthermore, we found that Atp6v0d2 promoted lysosomal degradation of Pu.1, which induced AAM polarization and Ccl17 production. Among asthma patients, ATP6V0d2 expression was inversely associated with disease severity, whereas PU.1 and CCL17 expression was positively associated with disease severity.

CONCLUSIONS

Our results identify macrophage Atp6v0d2, as an induced feedback inhibitor of asthma disease severity by promoting Pu.1 lysosomal degradation, which may in turn leads to reduced AAM polarization and Ccl17 production.