Category Archives: RESEARCH ARTICLE

A novel lncRNA LOC105613571 binding with BDNF in pituitary promotes gonadotropin secretion by AKT/ERK‐mTOR pathway in sheep associated with prolificacy

Posted on 11 July 2023 by

Candidate lncRNA LOC105613571 targeted BDNF via trans-regulated relationships was characterized by pituitary transcriptome from Hu sheep with high and low fecundity. GnRH stimulation increased BDNF and lncRNA LOC105613571 expression in pituitary cells. BDNF-binding lncRNA LOC105613571 promotes pituitary gonadotropin secretion by activating AKT/ERK-mTOR pathway in pituitary cells.

Abstract

The pituitary is a vital endocrine organ for synthesis and secretion of gonadotropic hormones (FSH and LH), and the gonadotropin showed fluctuations in animals with different fecundity. Long non-coding RNAs (lncRNAs) have been identified as regulatory factors for the reproductive process. However, the profiles of lncRNAs and their roles involved in sheep fecundity remains unclear. In this study, we performed RNA-sequencing for the sheep pituitary gland associated with different fecundity, and identified a novel candidate lncRNA LOC105613571 targeting BDNF related to gonadotropin secretion. Our results showed that expression of lncRNA LOC105613571 and BDNF could be significantly upregulated by GnRH stimulation in sheep pituitary cells in vitro. Notably, either lncRNA LOC105613571 or BDNF silencing inhibited cell proliferation while promoted cell apoptosis. Moreover, lncRNA LOC105613571 knockdown could also downregulate gonadotropin secretion via inactivation AKT, ERK and mTOR pathway. In addition, co-treatment with GnRH stimulation and lncRNA LOC105613571 or BDNF knockdown showed the opposite effect on sheep pituitary cells in vitro. In summary, BDNF-binding lncRNA LOC105613571 in sheep regulates pituitary cell proliferation and gonadotropin secretion via the AKT/ERK-mTOR pathway, providing new ideas for the molecular mechanisms of pituitary functions.

The influence of redox modulation on hypoxic endothelial cell metabolic and proteomic profiles through a small thiol‐based compound tuning glutathione and thioredoxin systems

Posted on 6 July 2023 by

The intracellular redox state of endothelial cells facing low oxygen and oxidative stress was regulated via the pro-glutathione molecule I-152, a co-drug of N-acetylcysteine and cysteamine. The principal redox couples, GSH/GSSG, and NAD(P)+/NAD(P)H were affected by hypoxia and in turn, modulated with I-152. Glutathione and thioredoxin-related pathways were enhanced after treatment and ROS production was alleviated. Strategies to fine-tune the redox balance could ameliorate the cell response to hypoxic environments.

Abstract

Reduction in oxygen levels is a key feature in the physiology of the bone marrow (BM) niche where hematopoiesis occurs. The BM niche is a highly vascularized tissue and endothelial cells (ECs) support and regulate blood cell formation from hematopoietic stem cells (HSCs). While in vivo studies are limited, ECs when cultured in vitro at low O₂ (<5%), fail to support functional HSC maintenance due to oxidative environment. Therefore, changes in EC redox status induced by antioxidant molecules may lead to alterations in the cellular response to hypoxia likely favoring HSC self-renewal. To evaluate the impact of redox regulation, HUVEC, exposed for 1, 6, and 24 h to 3% O₂ were treated with N-(N-acetyl-l-cysteinyl)-S-acetylcysteamine (I-152). Metabolomic analyses revealed that I-152 increased glutathione levels and influenced the metabolic profiles interconnected with the glutathione system and the redox couples NAD(P)+/NAD(P)H. mRNA analysis showed a lowered gene expression of HIF-1α and VEGF following I-152 treatment whereas TRX 1 and 2 were stimulated. Accordingly, the proteomic study revealed the redox-dependent upregulation of thioredoxin and peroxiredoxins that, together with the glutathione system, are the main regulators of intracellular ROS. Indeed, a time-dependent ROS production under hypoxia and a quenching effect of the molecule were evidenced. At the secretome level, the molecule downregulated IL-6, MCP-1, and PDGF-bb. These results suggest that redox modulation by I-152 reduces oxidative stress and ROS level in hypoxic ECs and may be a strategy to fine-tune the environment of an in vitro BM niche able to support functional HSC maintenance.

Nomilin and its analogue obacunone alleviate NASH and hepatic fibrosis in mice via enhancing antioxidant and anti‐inflammation capacity

Posted on 4 July 2023 by

Nomilin and obacunone exert beneficial effects on MCD-, BDL-, and CCl₄-induced NASH mice. Nomilin and obacunone alleviate NASH and liver fibrosis via enhancing antioxidant and anti-inflammation capacity.

Abstract

Nonalcoholic steatohepatitis (NASH) and hepatic fibrosis are leading causes of cirrhosis with rising morbidity and mortality worldwide. Currently, there is no appropriate treatment for NASH and hepatic fibrosis. Many studies have shown that oxidative stress is a main factor inducing NASH. Nomilin (NML) and obacunone (OBA) are limonoid compounds naturally occurring in citrus fruits with various biological properties. However, whether OBA and NML have beneficial effects on NASH remains unclear. Here, we demonstrated that OBA and NML inhibited hepatic tissue necrosis, inflammatory infiltration and liver fibrosis progression in methionine and choline-deficient (MCD) diet, carbon tetrachloride (CCl₄)-treated and bile duct ligation (BDL) NASH and hepatic fibrosis mouse models. Mechanistic studies showed that NML and OBA enhanced anti-oxidative effects, including reduction of malondialdehyde (MDA) level, increase of catalase (CAT) activity and the gene expression of glutathione S-transferases (GSTs) and Nrf2-keap1 signaling. Additional, NML and OBA inhibited the expression of inflammatory gene interleukin 6 (Il-6), and regulated the bile acid metabolism genes Cyp3a11, Cyp7a1, multidrug resistance-associated protein 3 (Mrp3). Overall, these findings indicate that NML and OBA may alleviate NASH and liver fibrosis in mice via enhancing antioxidant and anti-inflammation capacity. Our study proposed that NML and OBA may be potential strategies for NASH treatment.

Rigosertib is more potent than wortmannin and rapamycin against adult T‐cell leukemia‐lymphoma

Posted on 22 June 2023 by

HTLV-1 downregulation of the mRNA level may occur as a negative feedback response to increased PI3K-Akt-mTOR phosphorylation by HTLV-1. Rigosertib was more effective than wortmannin and rapamycin in inducing cell cycle arrest, as well as a significant late apoptosis in the Inf-3T3 and MT-2 cells.

Abstract

Human T lymphotropic virus type 1 (HTLV-1) infection can cause adult T-cell lymphoblastic leukemia (ATLL), an incurable, chemotherapy-resistant malignancy. In a quest for new therapeutic targets, our study sought to determine the levels of AKT, mTOR, and PI3K in ATLL MT-2 cells, HTLV-1 infected NIH/3T3 cells (Inf-3T3), and HTLV-1 infected patients (Carrier, HAM/TSP, and ATLL). Furthermore, the effects of rigosertib, wortmannin, and rapamycin on the PI3K/Akt/mTOR pathway to inhibit the proliferation of ATLL cells were examined. The results showed that mRNA expression of Akt/PI3K/mTOR was down-regulated in carrier, HAM/TSP, and ATLL patients, as well as MT-2, and Inf-3T3 cells, compared to the healthy individuals and untreated MT-2 and Inf-3T3 as controls. However, western blotting revealed an increase in the phosphorylated and activated forms of AKT and mTOR. Treating the cells with rapamycin, wortmannin, and rigosertib decreased the phosphorylated forms of Akt and mTOR and restored their mRNA expression levels. Using these inhibitors also significantly boosted the expression of the pro-apoptotic genes, Bax/Bcl-2 ratio as well as the expression of the tumor suppressor gene p53 in the MT-2 and Inf-3T3cells. Rigosertib was more potent than wortmannin and rapamycin in inducing sub-G1 and G2-M cell cycle arrest, as well as late apoptosis in the Inf-3T3 and MT-2 cells. It also synergized the cytotoxic effects of vincristine. These findings demonstrate that HTLV-1 downregulation of the mRNA level may occur as a negative feedback response to increased PI3K-Akt-mTOR phosphorylation by HTLV-1. Therefore, using rigosertib alone or in combination with common chemotherapy drugs may be beneficial in ATLL patients.

SUMO2/3 promotes the progression and oxaliplatin resistance of colorectal cancer through facilitating the SUMOylation at Ku80‐K307

Posted on 20 June 2023 by nDan Feng, nJinsong He, nMin Yuan, nQing Chen, nXi Zeng, nQilin Zhou, nJian Wu, nBin Hann

We describes the role for SUMO2/3 during oxaliplatin resistance in CRC and assessed the contribution of Ku80 SUMOylation in this process. Overexpression of SUMO2/3-promoted CRC cell proliferation, invasion, migration in vitro and in vivo. SUMOylation of K307 in Ku80 attenuated the DNA damage of CRC cells caused by oxaliplatin and was consistent with an antiapoptotic role for SUMO2/3.

Abstract

Colorectal cancer (CRC) is one of the most prevalent cancers worldwide and is typically treated with the FOLFOX regimen (folinic acid, 5-fluorouracil, and oxaliplatin). However, oxaliplatin resistance remains a serious clinical problem. In the present study, we found that SUMO2/3 was overexpressed in CRC tissues and exogenous overexpression of SUMO2/3 promoted CRC cell proliferation, extension, and invasion and positively regulated the cell cycle. In contrast, SUMO2/3 gene knockdowns inhibited migration and repressed cell viability in vitro and in vivo. In addition, we found that SUMO2/3 was recruited to the cell nucleus and suppressed oxaliplatin-induced apoptosis of CRC cells. Moreover, Ku80, a DNA-binding protein essential for the repair of DNA double-strand breaks, was confirmed to bind with SUMO2/3. Notably, Ku80 undergoes SUMOylation at K307 by SUMO2/3 and this correlated with apoptosis in CRC cells suffering oxaliplatin stress. Collectively, we found that SUMO2/3 plays a specific role in CRC tumorigenesis and acts through Ku80 SUMOylation which is linked with the development of CRC-oxaliplatin resistance.

Adipose tissue‐derived mesenchymal stem cells ameliorate cognitive impairment in Alzheimer’s disease rat model: Emerging role of SIRT1

Posted on 15 June 2023 by nMohamed Nabil, nDina H. Kassem, nAzza A. Ali, nHala O. El‐Mesallamyn

The present study aimed to investigate the therapeutic potential of adipose tissue-derived mesenchymal stem cells (Ad-MSCs) in Alzheimer's disease (AD) rat model, and to explore the possible implication of SIRT1. Our data demonstrated that transplantation of Ad-MSCs alleviated cognitive impairment in AD rats. Additionally, they exhibited anti-amyloidogenic, anti-apoptotic, anti-inflammatory, as well as neurogenic effects. Furthermore, Ad-MSCs were found to mediate their therapeutic effects, at least partially, via modulating both central and systemic SIRT1 levels. Hence, the current study portrays Ad-MSCs as an effective therapeutic approach for AD management and opens the door for future investigations to further elucidate the role of SIRT1 and its interrelated molecular mediators in AD.

Abstract

Alzheimer's disease (AD) is a complex form of neurodegenerative dementia. Growing body of evidence supports the cardinal role of sirtuin1 (SIRT1) in neurodegeneration and AD development. Recently, adipose tissue-derived mesenchymal stem cells (Ad-MSCs) have made their mark for a wide array of regenerative medicine applications, including neurodegenerative disorders. Therefore, the present study aimed to investigate the therapeutic potential of Ad-MSCs in AD rat model, and to explore the possible implication of SIRT1. Ad-MSCs were isolated from rat epididymal fat pads and properly characterized. Aluminum chloride was used to induce AD in rats, and afterward, a group of AD-induced rats received a single dose of Ad-MSCs (2 × 10⁶ cell, I.V per rat). One month after Ad-MSCs transplantation, behavioral tests were done, brain tissues were collected, then histopathological and biochemical assessments were performed. Amyloid beta and SIRT1 levels were determined by enzyme-linked immunosorbent assay. Whereas expression levels of neprilysin, BCL2 associated X protein, B-cell lymphoma-2, interleukin-1β, interleukin-6, and nerve growth factor in hippocampus and frontal cortex brain tissues were assessed using reverse transcriptase quantitative polymerase chain reaction. Our data demonstrated that transplantation of Ad-MSCs alleviated cognitive impairment in AD rats. Additionally, they exhibited anti-amyloidogenic, antiapoptotic, anti-inflammatory, as well as neurogenic effects. Furthermore, Ad-MSCs were found to possibly mediate their therapeutic effects, at least partially, via modulating both central and systemic SIRT1 levels. Hence, the current study portrays Ad-MSCs as an effective therapeutic approach for AD management and opens the door for future investigations to further elucidate the role of SIRT1 and its interrelated molecular mediators in AD.

Angiotensin II type 2 receptor as a novel activator of brown adipose tissue in obesity

Posted on 7 June 2023 by

Angiotensin II type 2 receptor as a noval activator of brown adipose tissue in obesity.

Abstract

The angiotensin II type 2 receptor (AT2R) exerts vasorelaxant, anti-inflammatory, and antioxidant properties. In obesity, its activation counterbalances the adverse cardiovascular effects of angiotensin II mediated by the AT1R. Preliminary results indicate that it also promotes brown adipocyte differentiation in vitro. Our hypothesis is that AT2R activation could increase BAT mass and activity in obesity. Five-week-old male C57BL/6J mice were fed a standard or a high-fat (HF) diet for 6 weeks. Half of the animals were treated with compound 21 (C21), a selective AT2R agonist, (1 mg/kg/day) in the drinking water. Electron transport chain (ETC), oxidative phosphorylation, and UCP1 proteins were measured in the interscapular BAT (iBAT) and thoracic perivascular adipose tissue (tPVAT) as well as inflammatory and oxidative parameters. Differentiation and oxygen consumption rate (OCR) in the presence of C21 was tested in brown preadipocytes. In vitro, C21-differentiated brown adipocytes showed an AT2R-dependent increase of differentiation markers (Ucp1, Cidea, Pparg) and increased basal and H⁺ leak-linked OCR. In vivo, HF-C21 mice showed increased iBAT mass compared to HF animals. Both their iBAT and tPVAT showed higher protein levels of the ETC protein complexes and UCP1, together with a reduction of inflammatory and oxidative markers. The activation of the AT2R increases BAT mass, mitochondrial activity, and reduces markers of tissue inflammation and oxidative stress in obesity. Therefore, insulin reduction and better vascular responses are achieved. Thus, the activation of the protective arm of the renin–angiotensin system arises as a promising tool in the treatment of obesity.