BMC Molecular and Cell Biology最新文献

Melanoma is the most lethal type of skin cancer that originates from the malignant transformation of melanocytes. Although novel treatments have improved patient survival in melanoma, the overall prognosis remains poor. To improve current therapies and patients outcome, it is necessary to identify the influential elements in the development and progression of melanoma.Due to UV exposure and melanin synthesis, the melanocytic lineage seems to have a higher rate of ROS (reactive oxygen species) formation. Melanoma has been linked to an increased oxidative state, and all facets of melanoma pathophysiology rely on redox biology. Several redox-modulating pathways have arisen to resist oxidative stress. One of which, the Nrf2 (nuclear factor erythroid 2-related factor 2), has been recognized as a master regulator of cellular response to oxidative or electrophilic challenges. The activation of Nrf2 signaling causes a wide range of antioxidant and detoxification enzyme genes to be expressed. As a result, this transcription factor has lately received a lot of interest as a possible cancer treatment target.On the other hand, Nrf2 has been found to have a variety of activities in addition to its antioxidant abilities, constant Nrf2 activation in malignant cells may accelerate metastasis and chemoresistance. Hence, based on the cell type and context, Nrf2 has different roles in either preventing or promoting cancer. In this study, we aimed to systematically review all the studies discussing the function of Nrf2 in melanoma and the factors determining its alteration.

Background: Bronchopulmonary dysplasia is a serious and lifelong pulmonary disease in premature neonates that influences around one-quarter of premature newborns. The wingless-related integration site /β-catenin signaling pathway, which is abnormally activated in the lungs with pulmonary fibrosis, affects cell differentiation and lung development.

Methods: Newborn rats were subjected to hyperoxia exposure. Histopathological changes to the lungs were evaluated through immunohistochemistry, and the activation of disheveled and Wnt /β-catenin signaling pathway components was assessed by Western blotting and real-time PCR. The abilities of proliferation, apoptosis and migration were detected by Cell Counting Kit-8, flow cytometry and scratch wound assay, respectively.

Results: Contrasting with normoxic lungs, hyperoxia-exposed lungs demonstrated larger alveoli, fewer alveoli and thicker alveolar septa. Superoxide dismutase activity was significantly decreased (7th day: P < 0.05; 14th day: P < 0.01) and malondialdehyde significantly increased (7th day: P < 0.05; 14th day: P < 0.01) after hyperoxia exposure. Protein and mRNA expression levels of β-catenin, Dvl-1, CTNNBL1 and cyclin D1 were significantly upregulated by hyperoxia exposure on 7th day (P < 0.01) and 14th day (P < 0.01). In hyperoxic conditions, Dvl-l downregulation and Dvl-l downregulation + MSAB treatment significantly increased the proliferation rates, decreased the apoptosis rates and improved the ability of cell migration. In hyperoxic conditions, Dvl-l downregulation could decrease the mRNA expression levels of GSK3β, β-catenin, CTNNBL1 and cyclin D1 and decrease the protein relative expression levels of GSK3β, p-GSK3β, β-catenin, CTNNBL1 and cyclin D1.

Conclusions: We confirmed the positive role of Dvl-1 and the Wnt/β-catenin signaling pathway in promoting BPD in hyperoxia conditions and provided a promising therapeutic target.

Background: Alterations in vascular smooth muscle cells (VSMCs) contribute to the pathogenesis of intracranial aneurysms (IAs). However, molecular mechanisms underlying these changes remain unknown. The present study aimed to characterize the molecular mechanisms underlying VSMC-mediated IAs.

Methods: Expression of the circular RNA circ-ATL1 and microRNA miR-455 was detected in IAs by RT-qPCR. Interactions between circ-ATL1, miR-455 and SIRT5 were examined by luciferase reporter analysis and RT-qPCR. The regulatory roles of circ-ATL1, miR-455 and SIRT5 in VSMC migration, proliferation and phenotypic modulation were also examined by CCK8, Transwell® migration and western blot assays.

Results: Biochemical and bioinformatic techniques were used to demonstrate that circ-ATL1 and miR-455 participated in disparate biological processes relevant to aneurysm formation. Clinically, increased expression of circ-ATL1 and downregulated miR-455 expression were observed in IA patients compared with healthy subjects. Silencing of circ-ATL1 led to suppression of VSMC migration, proliferation and phenotypic modulation. Both SIRT5 and miR-455 were found to be downstream targets of circ-ATL1. SIRT5 upregulation or miR-455 inhibition reversed the inhibitory effects induced by circ-ATL1 silencing on VSMC proliferation, migration and phenotypic modulation. We found that VSMC phenotypic modulation by circ-ATL1 upregulation and miR-455 downregulation had a critical role in the development and formation of AIs. Specifically, circ-ATL1 downregulation reversed IA formation.

Conclusion: Our data provide the theoretical basis for future studies on potential clinical treatment and prevention of IAs.

Autophagy and pyroptosis of macrophages play important protective or detrimental roles in sepsis. However, the underlying mechanisms remain unclear. High mobility group box protein 1 (HMGB1) is associated with both pyroptosis and autophagy. lipopolysaccharide (LPS) is an important pathogenic factor involved in sepsis. Lentivirus-mediated HMGB1 shRNA was used to inhibit the expression of HMGB1. Macrophages were treated with acetylation inhibitor (AA) to suppress the translocation of HMGB1 from the nucleus to the cytosol. Autophagy and pyroptosis-related protein expressions were detected by Western blot. The levels of caspase-1 activity were detected and the rate of pyroptotic cells was detected by flow cytometry. LPS induced autophagy and pyroptosis of macrophages at different stages, and HMGB1 downregulation decreased LPS-induced autophagy and pyroptosis. Treatment with acetylation inhibitor (anacardic acid) significantly suppressed LPS-induced autophagy, an effect that was not reversed by exogenous HMGB1, suggesting that cytoplasmic HMGB1 mediates LPS-induced autophagy of macrophages. Anacardic acid or an anti-HMGB1 antibody inhibited LPS-induced pyroptosis of macrophages. HMGB1 alone induced pyroptosis of macrophages and this effect was inhibited by anti-HMGB1 antibody, suggesting that extracellular HMGB1 induces macrophage pyroptosis and mediates LPS-induced pyroptosis. In summary, HMGB1 plays different roles in mediating LPS-induced autophagy and triggering pyroptosis according to subcellular localization.

Background: Tendon injury is associated with oxidative stress, leading to reactive oxygen species (ROS) production and inflammation. N-acetyl-L-cysteine (NAC) is a potent antioxidant. However, how NAC affects the biological functions of tendon stem/progenitor cells (TSPCs) and tendon repair has not been clarified.  METHOD: The impacts of NAC on the viability, ROS production, and differentiation of TSPCs were determined with the cell counting kit-8, fluorescence staining, Western blotting, and immunofluorescence. The effect of NAC on gene transcription in TSPCs was analyzed by transcriptomes and bioinformatics and validated by Western blotting. The potential therapeutic effect of NAC on tendon repair was tested in a rat model of Achilles tendon injury.

Results: Compared with the untreated control, treatment with 500 µM NAC greatly promoted the proliferation of TSPCs and significantly mitigated hydrogen peroxide-induced ROS production and cytotoxicity in vitro. NAC treatment significantly increased the relative protein expression of collagen type 1 alpha 1 (COL1A1), tenascin C (TNC), scleraxis (SCX), and tenomodulin (TNMD) in TPSCs. Bioinformatics analyses revealed that NAC modulated transcriptomes, particularly in the integrin-related phosphoinositide 3-kinase (PI3K)/AKT signaling, and Western blotting revealed that NAC enhanced integrin α5β1 expression and PI3K/AKT activation in TSPCs. Finally, NAC treatment mitigated the tendon injury, but enhanced the protein expression of SCX, TNC, TNMD, and COLIA1 in the injured tissue regions of the rats.

Conclusion: NAC treatment promoted the survival and differentiation of TSPCs to facilitate tendon repair after tendon injury in rats. Thus, NAC may be valuable for the treatment of tendon injury.

Background: Considering the high correlation between the functional decline in Alzheimer's disease (AD) and the propagation of aggregated tau protein, many research efforts are focused on determining the underlying molecular mechanisms of tau spreading. Heparan sulfate proteoglycans (HSPGs) were reported to mediate cellular uptake of tau aggregates. Specifically, the heparan sulfates (HS) sulfation plays a critical role in the interaction of HSPGs with aggregated tau. HS can be N-/2-O/6-O- or 3-O-sulfated, some of which have been reported to take part in the interaction with tau aggregates. However, the role of the 3-O sulfation remains enigmatic.

Results: Here, we studied the contribution of HS 3-O sulfation in the binding and cellular uptake of tau aggregates. We observed reduced tau aggregates uptake in absence of 3-O sulfation or when outcompeting available cellular 3-O sulfated HS (3S-HS) with antithrombin III. The lack of HS3ST1-generated HS products in the HS3ST1^-/- cells was further corroborated with an LC-MS/MS using ¹³C-labeled HS calibrants. Here, we showed that these functional changes can be explained by a higher affinity of aggregated tau to 3S-HS. When targeting tau aggregates with 3-O sulfation-containing HS, we observed an increase in inhibition of tau aggregates uptake.

Conclusions: These data indicate that HS 3-O sulfation plays a role in the binding of tau aggregates and, thus, contributes to their cellular uptake, highlighting a potential target value to modulate tau pathogenesis.

Background: Inflammation is the most common cause of kidney damage, and inflammatory responses in a number of diseases are mediated by microRNA-338-3p (miR-338-3p). However, there are only a few reports which described the regulation of miR-338-3p in human proximal tubular cells. The goal of this study was to see how miR-338-3p affected lipopolysaccharide (LPS)-caused inflammatory response in HK-2 cells.

Methods: LPS was used to construct an inflammatory model in HK-2 cells. miR-338-3p mimic was used to increase the levels of miR-338-3p in HK-2 cells. MTT, JC-1 staining, and apoptosis assays were used to detect cell viability, mitochondrial membrane potential (MMP), and apoptosis, respectively. The production of inflammatory factors and the levels of p38, p65, phospho-p65, phospho-p38, Bax, Bcl-2, cleaved caspase-9, and cleaved caspase-3 were investigated using real-time polymerase chain reaction, western blotting, or enzyme-linked immunosorbent assay.

Results: The levels of miR-338-3p were significantly lower in serum from patients with sepsis-induced kidney injury compared to the serum from healthy volunteers (P < 0.05). LPS reduced the level of miR-338-3p in HK-2 cells (P < 0.05). HK-2 cell viability, mitochondrial membrane potential, and Bcl-2 mRNA and protein levels were decreased by LPS (all P < 0.05). Apoptosis, the mRNA and protein levels of inflammatory cytokines (IL-1β, IL-6, IL-8, and TNF-α) and Bax, and the levels of cleaved caspase-9 and caspase-3 were increased by LPS (all P < 0.05). Raising the level of miR-338-3p mitigated these effects of LPS (all P < 0.05).

Conclusion: LPS-induced inflammation in HK-2 cells is reduced by miR-338-3p.

Background: Oral squamous cell carcinoma (OSCC) is one of the most common head and neck cancers. Long non-coding RNA HOXA-AS2 (lncRNA HOXA-AS2) have been extensively studied in various cancers. However, the expression and function of HOXA-AS2 in OSCC still remain unknown. The aim of this study is to investigate the roles of HOXA-AS2 in OSCC.

Methods: OSCC tissues and adjacent normal tissues were obtained from OSCC patients. RT-qPCR and Western blot assays were used to detect the expression of target genes in OSCC tissues or cells. Cells proliferation, migration and invasion were detected by CCK-8 and transwell assays, respectively. The target gene of HOXA-AS2 was confirmed by dual-luciferase reporter gene assay.

Results: We found that HOXA-AS2 expression was remarkably upregulated in OSCC tissues and cell lines. The downregulation of HOXA-AS2 inhibited cells proliferation, migration and invasion. Our bioinformatics analysis found that HOXA-AS2 can target miR-520c-3p, which was confirmed by dual-luciferase reporter gene assay. The expression of HOXA-AS2 was found to be negatively associated with miR-520c-3p in OSCC tissues. Moreover, sorting nexin 5 (SNX5), a downstream target of miR-520c-3p, was inhibited by miR-520c-3p overexpression. SNX5 was also increased in OSCC tissues and cell lines. Additionally, we found that the higher expression of SNX5 was strongly associated with the tumor grade of OSCC patients in Oncomine database. Most importantly, the knockdown of HOXA-AS2 induced cells apoptosis by promoting autophagy by regulating SNX5.

Conclusion: HOXA-AS2 served an oncogene and promoted OSCC progression via the miR-520c-3p/SNX5 axis. Thus, HOXA-AS2 may be a new biomarker for diagnosis and treatment of OSCC.

Background: Cold inducible RNA-binding protein (CIRP) is a key protein in the hypothermic therapy. Highly expressed CIRP exerts a neuroprotective effect on neurons. The aim of this study is to provide the evidence of the protective effects of CIRP on the glial cells and explore the downstream pathway of CIRP.

Results: The results of this study demonstrated that the cell viability of the glial cells with CIRP overexpression was increased significantly compared to the control. With CIRP overexpression, the epidermal growth factor (EGF) mRNA expression was found increasing significantly and the mRNA expressions of derived neurotrophic factor (BDNF), bcl-2, vascular endothelial growth factor (VEGF) and nerve growth factor (NGF) were not upregulated compared to the control. EGF and CIRP co-expression was demonstrated on the glial cells. With CIRP expression, EGF expression on the glial cells was increased statistically compared to the control.

Conclusion: CIRP overexpression increases the cell viability of the glial cells, exerting a neuroprotective effect. EGF expression is activated on the glial cells with CIRP overexpression, implying a pathway of CIRP neuroprotection via EGF activation.

Background: Melanoma is a common type of skin cancer, and its incidence is increasing gradually. Exploring melanoma pathogenesis helps to find new treatments.

Objective: We aimed to explore the potential molecular mechanisms by which CREB1 regulates melanoma.

Methods: TransmiR and ALGGEN were used to predict targets of CREB1 in the promoter of miR-495-3p or miR-495-3p and KPNA2, and a dual-luciferase reporter assay was performed to detect binding of CREB1 to these promoters. In addition, binding of CREB1 to the miR-495-3p promoter was confirmed by a ChIP assay. qRT‒PCR was carried out to detect mRNA levels of miR-495-3p, CREB1 and KPNA2. An EdU assay was conducted to detect cell viability. Transwell assays and flow cytometry were performed to assess cell migration and invasion and apoptosis, respectively. Moreover, factors associated with overall survival were analysed by using the Cox proportional hazards model.

Results: Our results show miR-495-3p to be significantly decreased in melanoma. Additionally, miR-495-3p overexpression inhibited melanoma cell viability. CREB1 targeted miR-495-3p, and CREB1 overexpression enhanced melanoma cell viability by inhibiting miR-495-3p transcription. Moreover, miR-495-3p targeted KPNA2, and CREB1 regulated KPNA2 by inhibiting miR-495-3p transcription to enhance melanoma cell viability.

Conclusion: CREB1 regulates KPNA2 by inhibiting miR-495-3p transcription to control melanoma progression. Our results indicate the molecular mechanism by which the CREB1/miR-495-3p/KPNA2 axis regulates melanoma progression.