Pterostilbene protects against H2 O2 -induced oxidative stress by regulating GAS6/Axl signaling in HL-1 cells.

Pterostilbene (PTE, trans-3,5-dimethoxy-4'-hydroxystilbene), a natural plant polyphenol, possesses numerous pharmacological effects, including antioxidant, antidiabetic, antiatherosclerotic, and neuroprotective aspects. This study aims to investigate whether PTE plays a protective role against oxidative stress injury by GAS6/Axl signaling pathway in cardiomyocytes. Hydrogen peroxide (H2 O2 )-induced oxidative stress HL-1 cells were used as models. The mechanism by which PTE protected oxidative stress is investigated by combining cell viability, cell ROS levels, apoptosis assay, molecular docking, quantitative real-time PCR, and western blot analysis. GAS6 shRNA was performed to investigate the involvement of GAS6/Axl pathways in PTE's protective role. The results showed that PTE treatment improved the cell morphology and viability, and inhibited the apoptosis rate and ROS levels in H2 O2 -injured HL-1 cells. Particularly, PTE treatment upregulated the levels of GAS6, Axl, and markers related to oxidative stress, apoptosis, and mitochondrial function related. Molecular docking showed that PTE and GAS6 have good binding ability. Taken together, PTE plays a protective role against oxidative stress injury through inhibiting oxidative stress and apoptosis and improving mitochondrial function. Particularly, GAS6/Axl axis is the surprisingly prominent in the PTE-mediated pleiotropic effects.

CC chemokines family in fibrosis and aging: From mechanisms to therapy.

Fibrosis is a universal aging-related pathological process in the different organ, but is actually a self-repair excessive response. To date, it still remains a large unmet therapeutic need to restore injured tissue architecture without detrimental side effects, due to the limited clinical success in the treatment of fibrotic disease. Although specific organ fibrosis and the associated triggers have distinct pathophysiological and clinical manifestations, they often share involved cascades and common traits, including inflammatory stimuli, endothelial cell injury, and macrophage recruitment. These pathological processes can be widely controlled by a kind of cytokines, namely chemokines. Chemokines act as a potent chemoattractant to regulate cell trafficking, angiogenesis, and extracellular matrix (ECM). Based on the position and number of N-terminal cysteine residues, chemokines are divided into four groups: the CXC group, the CX3C group, the (X)C group, and the CC group. The CC chemokine classes (28 members) is the most numerous and diverse subfamily of the four chemokine groups. In this Review, we summarized the latest advances in the understanding of the importance of CC chemokine in the pathogenesis of fibrosis and aging and discussed potential clinical therapeutic strategies and perspectives aimed at resolving excessive scarring formation.

GAS6/Axl is associated with AMPK activation and attenuates H2O2-induced oxidative stress.

Oxidative stress plays a key part in cardiovascular event. Growth arrest-specific gene 6 (GAS6) is a vitamin K-dependent ligand which has been shown to exert important effects in heart. The effects of GAS6 were evaluated against hydrogen peroxide (H2O2) ­induced oxidative stress injury in HL-1 cardiomyocytes. A series of experimental methods were used to analyze the effects of GAS6 on cell viability, apoptosis, oxidative stress, mitochondrial function and AMPK/ACC signaling in H2O2­injured HL-1 cells. In this study, we found that H2O2 reduced cell viability, increased apoptotic rate and intracellular reactive oxygen species (ROS). Meanwhile, H2O2 decreased the protein levels of GAS6, and increased the protein level of p-AMPK/AMPK, p-ACC/ACC. Then, we observed that overexpression of GAS6 significantly reduced cell death, manifested as increased cell viability, improved oxidative stress, apoptosis and upregulated the levels of GAS6, p-Axl/Axl, Nrf2, NQO1, HO-1, Bcl-2/Bax, PGC-1α, NRF1, TFAM, p-AMPK/AMPK, and p-ACC/ACC-related protein expression in HL-1 cells and H2O2­injured cardiomyocytes. To further verify the results, we successfully constructed GAS6 lentiviral vectors, and found GAS6 shRNA partially reversed the above results. These data suggest that AMPK/ACC may be a downstream effector molecule in the antioxidant action of GAS6. In summary, our findings indicate that activation GAS6/Axl-AMPK signaling protects H2O2­induced oxidative stress which is accompanied by the amelioration of oxidative stress, apoptosis, and mitochondrial function.

Psoralidin protects against cerebral hypoxia/reoxygenation injury: Role of GAS6/Axl signaling.

Psoralidin (PSO) is a natural phenolic coumarin extracted from the seeds of Psoralea corylifolia L. Growing preclinical evidence indicates that PSO has anti-inflammatory, anti-vitiligo, anti-bacterial, and anti-viral effects. Growth arrest-specific gene 6 (GAS6) and its receptor, Axl, modulate cellular oxidative stress, apoptosis, survival, proliferation, migration, and mitogenesis. Notably, the neuroprotective role of the GAS6/Axl axis has been identified in previous studies. We hypothesize that PSO ameliorates cerebral hypoxia/reoxygenation (HR) injury via activating the GAS6/Axl signaling. We first confirmed that PSO was not toxic to the cells and upregulated GAS6 and Axl expression after HR injury. Moreover, PSO exerted a marked neuroprotective effect against HR injury, represented by restored cell viability and cell morphology, decreased lactate dehydrogenase (LDH) release, and reactive oxygen species (ROS) generation. Furthermore, PSO pretreatment also elevated the levels of nuclear factor-related factor 2 (Nrf-2), NAD(P)H dehydrogenase quinone-1 (NQO1), heme oxygenase-1 (HO-1), silent information regulator 1 (SIRT1), peroxisome proliferator-activated receptor coactivator 1α (PGC-1α), nuclear respiratory factor 1 (NRF1), uncoupling protein 2 (UCP2), and B-cell lymphoma 2 (BCl2) both in the condition of baseline and HR injury. However, GAS6 siRNA or Axl siRNA inhibited the neuroprotective effects of PSO. Our findings suggest that PSO pretreatment attenuated HR-induced oxidative stress, apoptosis, and mitochondrial dysfunction in neuroblastoma cells through the activation of GAS6/Axl signaling.

Omentin-1: a newly discovered warrior against metabolic related diseases.

INTRODUCTION: Chronic metabolism-related diseases are challenging clinical problems. Omentin-1 is mainly expressed in stromal vascular cells of adipose tissue and can also be expressed in airway goblet cells, mesothelial cells, and vascular cells. Omentin-1 has been found to exert important anti-inflammatory, antioxidative and anti-apoptotic roles and to regulate endothelial dysfunction. Moreover, omentin-1 also has protective effects against cancer, atherosclerosis, type 2 diabetes mellitus, and bone metabolic diseases. The current review will discuss the therapeutic potential of omentin-1. AREAS COVERED: This review summarizes the biological actions of omentin-1 and provides an overview of omentin-1 in metabolic-related diseases. The relevant literature was derived from a PubMed search spanning 1998-2021 using these search terms: omentin-1, atherosclerosis, diabetes mellitus, bone, cancer, inflammation, and oxidative stress. EXPERT OPINION: As a novel adipocytokine, omentin-1 is a promising therapeutic target in metabolic-related diseases. Preclinical animal studies have shown encouraging results. Moreover, circulating omentin-1 has excellent potential as a noninvasive biomarker. In the future, strategies for regulating omentin-1 need to be investigated further in clinical trials in a large cohort.

Neuroprotective Effects of Omentin-1 Against Cerebral Hypoxia/Reoxygenation Injury via Activating GAS6/Axl Signaling Pathway in Neuroblastoma Cells.

Ischemic stroke is characterized by insufficient blood supply to brain tissue and is associated with increased morbidity and mortality in adults worldwide. Growth arrest-specific protein 6 (GAS6) is a vitamin K-dependent protein and is widely expressed in the central nervous system. The biological functions of GAS6 are mediated by the interaction with TAM (Tyro3, Axl and Mertk) receptors, including cell survival and proliferation, immune regulation and apoptosis. Omentin-1, also known as intelectin-1 (ITLN-1), is a novel adipocytokine that is involved in a variety of biological events, such as insulin resistance, endothelial dysfunction, programmed cell death and metabolic disorders. Our previous study has found that omentin-1 act as a novel regulator of vascular and anti-apoptotic response in cerebral ischemia. However, the specific molecular mechanism of omentin-1's protective effect on cerebral ischemia-reperfusion injury (IRI) is still unclear. First, the toxicity of recombinant human omentin-1 (rh-omentin) was assessed and a safe concentration was chosen for the next experiments. Then, rh-omentin exerted neuroprotection against hypoxia/reoxygenation (H/R) injury in N2a cells, indicated by increased cell viability, decreased LDH, ROS generation, and cell apoptotic rate. Furthermore, the similar protective effect was observed in omentin-1 overexpression cells constructed by lentivirus transfection. Rh-omentin could also inhibit H/R-induced apoptotic molecules, oxidative stress molecules, and GAS6/Axl signaling molecules which as evidence by increased omentin-1, GAS6, Axl, p-Axl, NQO1, HO-1, Nrf2, Bcl2 and decreased Bax expressions. However, GAS6 siRNA could reverse rh-omentin-induced neuroprotection and the levels of these molecules mentioned above. In conclusion, these findings suggest that omentin-1 treatment exerts neuroprotection against H/R injury partly via activating GAS6/Axl signaling at least. Therefore, these finding may favor omentin-1 a potential neuroprotective drug candidate to alleviate ischemia-reperfusion injury in clinic.

MicroRNA-134 suppresses cell proliferation in gastric cancer cells via targeting of GOLPH3.

Emerging evidence has shown that microRNAs (miRNAs) play critical roles in tumor development and progression. miR-134 has been found to act as a tumor-suppressor in numerous types of cancers. However, little is known concerning the potential role of miR-134 in gastric carcinogenesis. In the present study, we found that miR-134 was highly downregulated in gastric cancer tissues and cell lines when compared with levels in their adjacent non-tumor tissues and the normal human gastric epithelial cell line GES-1. Additionally, overexpression of miR-134 was accompanied by reduced cell proliferation in vitro and decreased tumor size in vivo. Further investigation by luciferase reporter assay indicated that Golgi phosphoprotein 3 (GOLPH3), a potent oncogene, was a direct target of miR-134. The activity of a luciferase reporter carrying the miR-134 binding site in the 3'-untranslated region (3'-UTR) of GOLPH3 was repressed by overexpression of miR-134, while a mutation in the 3'-UTR of GOLPH3 abrogated this effect, indicating that GOLPH3 is a target gene of miR-134. Overexpression of GOLPH3 blocked the antiproliferative effect of pre-miR-134 in gastric carcinoma cells. Furthermore, overexpression of miR-134 was associated with decreased phosphorylation of AKT, mTOR and S6K. Taken together, these data suggest that miR-134 regulates gastric cancer cell proliferation, at least potentially, through downregulation of the GOLPH3 gene, implicating a candidate tumor-suppressor miRNA in the pathogenesis of gastric cancer.

A CK19(CreERT) knockin mouse line allows for conditional DNA recombination in epithelial cells in multiple endodermal organs.

Cre/LoxP-mediated DNA recombination allows for gene function and cell lineage analyses during embryonic development and tissue regeneration. Here, we describe the derivation of a K19(CreERT) mouse line in which the tamoxifen-activable CreER(T) was knocked into the endogenous cytokeratin 19 locus. In the absence of tamoxifen, leaky Cre activity could be detected only in less than 1% of stomach and intestinal epithelial cells, but not in pancreatic or hepatic epithelial tissues. Tamoxifen administration in postnatal animals induced widespread DNA recombination in epithelial cells of pancreatic ducts, hepatic ducts, stomach, and intestine in a dose-dependent manner. Significantly, we found that Cre activity could be induced in the putative gut stem/progenitor cells that sustained long-term gut epithelial expression of a Cre reporter. This mouse line should therefore provide a valuable reagent for manipulating gene activity and for cell lineage marking in multiorgans during normal tissue homeostasis and regeneration.