Bnip3 interacts with vimentin, an intermediate filament protein, and regulates autophagy of hepatic stellate cells

Retinoic Acid-Related Orphan Receptor Alpha May Regulate the State of Hair Follicle Stem Cells by Upregulating the Expression of BNIP3

The hair, an exclusive keratinized dermal appendage in mammals, stands as a quintessential outcome of adaptive evolution, conferring resilience against adverse environmental conditions. The ontogenesis of the coat displays a pronounced rhythmic pattern, with hair follicle stem cells (HFSCs) emerging as pivotal facilitators of hair follicle reconstitution. The retinoic acid-related orphan receptor alpha, a nuclear receptor with extensive involvement in the regulation of cellular physiological states, exerts its functions predominantly through the modulation of downstream target gene transcription. The Bnip3 gene exhibits a robust correlation with cellular apoptosis and autophagy, which are indispensable physiological mechanisms underlying the maintenance of HFSC homeostasis. Consequently, the expression level of Bnip3 may be intimately linked to the status of HFSCs. In this investigative endeavor, we employed rat HFSCs as a model system to validate the regulatory impact of RORA on Bnip3 gene expression. Our findings unequivocally demonstrate that Bnip3 serves as a direct downstream target of RORA. Specifically, RORA binds to the motif within the Bnip3 promoter region, thereby upregulating Bnip3 expression levels. In light of our research findings, we propose that RORA holds potential as a target for modulating the status of HFSCs.

Qilong Capsule Alleviated MPTP-Induced Neuronal Defects by Inhibiting Apoptosis, Regulating Autophagy in Zebrafish Embryo Model

Qilong capsule (QLC) originates from the famous "Buyang Huanwu decoction" prescription. It is representative of drugs used in China during recovery from stroke, but its neuroprotective mechanism of action remains obscure. HPLC was used to evaluate the similarity of 10 batches of QLC samples. Then we used a zebrafish model to study the neuroprotective effect of QLC. At 24 hpf, embryos were treated with QLC and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), and zebrafish were observed the neuronal length and the number of apoptotic cells in the brain at 72 hpf. At 120 hpf, we conduct zebrafish behavioural tests. We then also used qPCR to detect the expression of genes related to autophagy and apoptosis. The results showed that QLC significantly reduced the damage of dopaminergic neurons, the number of apoptotic cells in the brain, and alleviated motor disturbances induced by MPTP. We found that the mechanism of QLC activity involved decreased neuron cell death by inhibiting mitochondrial apoptosis and autophagy, promoting autophagy, degradation of alpha-synuclein, and neuron cell growth, and rescuing the function of neurons damaged by MPTP. The results indicated that QLC protected against MPTP-induced neuron injury and provided pharmacological evidence for clinical use of QLC.

New insights into the interplay between autophagy and oxidative and endoplasmic reticulum stress in neuronal cell death and survival

Autophagy is a dynamic process that maintains the normal homeostasis of cells by digesting and degrading aging proteins and damaged organelles. The effect of autophagy on neural tissue is still a matter of debate. Some authors suggest that autophagy has a protective effect on nerve cells, whereas others suggest that autophagy also induces the death of nerve cells and aggravates nerve injury. In mammals, oxidative stress, autophagy and endoplasmic reticulum stress (ERS) constitute important defense mechanisms to help cells adapt to and survive the stress conditions caused by physiological and pathological stimuli. Under many pathophysiological conditions, oxidative stress, autophagy and ERS are integrated and amplified in cells to promote the progress of diseases. Over the past few decades, oxidative stress, autophagy and ERS and their interactions have been a hot topic in biomedical research. In this review, we summarize recent advances in understanding the interactions between oxidative stress, autophagy and ERS in neuronal cell death and survival.

The regulatory role and mechanism of autophagy in energy metabolism-related hepatic fibrosis

Hepatic fibrosis is a key pathological process of chronic liver diseases, caused by alcohol, toxic and aberrant energy metabolism. It progresses to cirrhosis or even hepatic carcinoma without effective treatment. Studies have shown that autophagy has important regulatory effects on hepatic stellate cells (HSCs) energy metabolism, and then affect the activation state of HSCs. Autophagy maintains hepatic energy homeostasis, and the dysregulation of autophagy can lead to the activation of HSCs and the occurrence and development of hepatic fibrosis. It is necessary to explore the mechanism of autophagy in energy metabolism-related hepatic fibrosis. Herein, the current study summarizes the regulating mechanisms of autophagy through different targets and signal pathways in energy metabolism-related hepatic fibrosis, and discusses the regulatory effect of autophagy by natural plant-derived, endogenous and synthetic compounds for the treatment of hepatic fibrosis. A better comprehension of autophagy in hepatic stellate cells energy metabolism-related hepatic fibrosis may provide effective intervention of hepatic fibrosis, explore the potential clinical strategies and promote the drug treatment of hepatic fibrosis.

Profiles of messenger RNAs and MicroRNAs in hypoxia-induced hepatic stellate cells

Background

MicroRNA (miRNA) plays an important role in hepatic stellate cell (HSCs) activation and liver fibrosis. The purpose of this study is to explore the effect of hypoxia on the differential expression of mRNAs and miRNAs in rat HSCs.

Methods

HSC-T6 cells were treated with cobalt chloride (CoCl₂), and the activity of HSC-T6 cells was measured by the CCK-8 assay. The mRNA expression levels of hypoxia inducible factor-1α (HIF-1α), collagen type I, transforming growth factor-β1 (TGF-β1), and Smad7 were measured by RT-qPCR. The protein expression levels of HIF-1α, Bax, Bcl-2, and caspase-3 were assayed by western blot. We used basal medium and 400 µmol/L CoCl₂ medium to treat HSC-T6 cells for 48 h. Cells were harvested after 48 h to extract RNA. Transcriptome sequencing was performed to investigate differentially expressed miRNAs and mRNAs (fold change >2; P<0.05). Bioinformatics analysis was performed to predict the functions of differentially expressed miRNAs and mRNAs. Further, we used RT-qPCR to detect the expression of mRNAs and miRNAs to confirm the accuracy of sequencing.

Results

With the increase of CoCl₂ concentration, the activity of HSC-T6 cells decreased (P<0.05). The mRNA expression levels of HIF-1α, collagen I, TGF-β1, and Smad7, and the protein expressions levels of HIF-1α, Bax, caspase-3, and the Bcl-2/Bax ratio were increased compared with the control group (P<0.05), while the expression of Bcl-2 decreased. A total of 54 miRNAs (20 upregulated and 34 downregulated) and 1,423 mRNAs (685 upregulated and 738 downregulated) were differentially expressed in the 400 µmol/L CoCl₂ medium group compared to the control basal medium group. Further bioinformatics analysis demonstrated that the differentially expressed mRNAs and miRNAs were mainly enriched in the synthesis of extracellular matrix. In addition, we used RT-qPCR to detect the expression of mRNAs and miRNAs to confirm the accuracy of sequencing.

Conclusions

Our results presented the profiles of mRNAs and miRNAs in hypoxia-induced HSC-T6 cells in rats, the signaling pathways, and co-expression networks. These findings may suggest novel insights for the early diagnosis and treatment of HSC activation and liver fibrosis.

Hypoxia, Hypoxia-Inducible Factors and Liver Fibrosis

Liver fibrosis is a potentially reversible pathophysiological event, leading to excess deposition of extracellular matrix (ECM) components and taking place as the net result of liver fibrogenesis, a dynamic and highly integrated process occurring during chronic liver injury of any etiology. Liver fibrogenesis and fibrosis, together with chronic inflammatory response, are primarily involved in the progression of chronic liver diseases (CLD). As is well known, a major role in fibrogenesis and fibrosis is played by activated myofibroblasts (MFs), as well as by macrophages and other hepatic cell populations involved in CLD progression. In the present review, we will focus the attention on the emerging pathogenic role of hypoxia, hypoxia-inducible factors (HIFs) and related mediators in the fibrogenic progression of CLD.