Full anti-apoptotic function of Bcl-XL complexed with Beclin-1 verified by live-cell FRET assays

Chinese Medicine for the Treatment of Liver Cirrhosis: The Mechanism of Cellular Autophagy

Liver cirrhosis is a critical stage in the progression of various chronic liver diseases, often leading to severe complications such as ascites, hepatic encephalopathy, and a high mortality rate, and it thus poses a serious threat to patient life. The activation of hepatic stellate cells is a central driver of disease progression. Cellular autophagy, a lysosome-mediated degradation process, plays a key role in maintaining cellular function and dynamic homeostasis. Research has shown that autophagy is closely associated with proteins like LC3, Beclin-1, P62, and mTOR, and is regulated through signaling pathways such as PI3K/Akt/mTOR, Ras/Raf/MEK/ERK, and AMPK/mTOR. Additionally, the relationship between autophagy and apoptosis, as well as between autophagy and exosomes, has been further demonstrated. While modern medicine has made progress in treating cirrhosis, it still faces significant limitations. By contrast, numerous studies have demonstrated the efficacy of traditional Chinese medicine in preventing and treating liver cirrhosis by regulating autophagy, with fewer adverse effects. Chinese herbal monomers and formulations can modulate various autophagy-related signaling pathways, including PI3K/Akt/mTOR, Ras/Raf/MEK/ERK, and AMPK/mTOR, and influence key autophagy proteins such as LC3 and Beclin-1. This modulation inhibits hepatic stellate cell activation, reduces extracellular matrix deposition, and exerts anticirrhotic effects. Moreover, Chinese medicine appears to reduce adverse reactions in cirrhosis treatment and lower the risk of disease recurrence. This review explores the mechanisms of autophagy in the prevention and treatment of liver cirrhosis through Chinese medicine, offering new insights for the development of Chinese medicinal therapies for cirrhosis and their rational clinical application.

Modulatory effects of curcumin on Singapore grouper iridovirus infection-associated apoptosis and autophagy in vitro

Singapore grouper iridovirus (SGIV) with high pathogenicity can cause great economic losses to aquaculture industry. Thus, it is of urgency to find effective antiviral strategies to combat SGIV. Curcumin has been demonstrated effective antiviral activity on SGIV infection. However, the molecular mechanism behind this action needs to be further explanations. In view of the fact that apoptosis (type I programmed cell death) and autophagy (type II programmed cell death) were key regulators during SGIV infection, we aimed to investigate the relevance between antiviral activity of curcumin and SGIV-associated programmed and clarify the role of potential signaling pathways. Our results showed that curcumin suppressed SGIV-induced apoptosis. At the same time, the activities of caspase-3/8/9 and activating protein-1 (AP-1), P53, nuclear factor-κB (NF-ΚB) promoters were inhibited. Besides, the activation of extracellular regulated protein kinases (ERK), c-Jun N-terminal kinase (JNK) and p38 mitogen activate protein kinase (p38 MAPK) signal pathways were suppressed in curcumin-treated cells. On the other hand, curcumin down-regulated protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway to promote autophagy representing by increased LC3 II and Beclin1 expression. Curcumin also hindered the transition of cells from G1 to S phase, as well as down-regulating the expression of CyclinD1. Our findings revealed the resistance curcumin induced to the effects of DNA virus on cell apoptosis and autophagy and the insights gained from this study may be of assistance to understand the molecular mechanism of curcumin against DNA virus infection.

Aberrant Bcl-x splicing in cancer: from molecular mechanism to therapeutic modulation

Bcl-x pre-mRNA splicing serves as a typical example to study the impact of alternative splicing in the modulation of cell death. Dysregulation of Bcl-x apoptotic isoforms caused by precarious equilibrium splicing is implicated in genesis and development of multiple human diseases, especially cancers. Exploring the mechanism of Bcl-x splicing and regulation has provided insight into the development of drugs that could contribute to sensitivity of cancer cells to death. On this basis, we review the multiple splicing patterns and structural characteristics of Bcl-x. Additionally, we outline the cis-regulatory elements, trans-acting factors as well as epigenetic modifications involved in the splicing regulation of Bcl-x. Furthermore, this review highlights aberrant splicing of Bcl-x involved in apoptosis evade, autophagy, metastasis, and therapy resistance of various cancer cells. Last, emphasis is given to the clinical role of targeting Bcl-x splicing correction in human cancer based on the splice-switching oligonucleotides, small molecular modulators and BH3 mimetics. Thus, it is highlighting significance of aberrant splicing isoforms of Bcl-x as targets for cancer therapy.

Autophagy in Viral Development and Progression of Cancer

Autophagy is a complex degradative process by which eukaryotic cells capture cytoplasmic components for subsequent degradation through lysosomal hydrolases. Although this catabolic process can be triggered by a great variety of stimuli, action in cells varies according to cellular context. Autophagy has been previously linked to disease development modulation, including cancer. Autophagy helps suppress cancer cell advancement in tumor transformation early stages, while promoting proliferation and metastasis in advanced settings. Oncoviruses are a particular type of virus that directly contribute to cell transformation and tumor development. Extensive molecular studies have revealed complex ways in which autophagy can suppress or improve oncovirus fitness while still regulating viral replication and determining host cell fate. This review includes recent advances in autophagic cellular function and emphasizes its antagonistic role in cancer cells.

Autophagy in Viral Development and Progression of Cancer

Autophagy is a complex degradative process by which eukaryotic cells capture cytoplasmic components for subsequent degradation through lysosomal hydrolases. Although this catabolic process can be triggered by a great variety of stimuli, action in cells varies according to cellular context. Autophagy has been previously linked to disease development modulation, including cancer. Autophagy helps suppress cancer cell advancement in tumor transformation early stages, while promoting proliferation and metastasis in advanced settings. Oncoviruses are a particular type of virus that directly contribute to cell transformation and tumor development. Extensive molecular studies have revealed complex ways in which autophagy can suppress or improve oncovirus fitness while still regulating viral replication and determining host cell fate. This review includes recent advances in autophagic cellular function and emphasizes its antagonistic role in cancer cells.

Identification of Beclin-1 from orange-spotted grouper (Epinephelus coioides) involved in viral infection

Beclin-1 is an essential autophagic regulator that plays diverse roles in physiology and disease. However, reports about the function of fish Beclin-1 during pathogen infection are still very limited. In this study, a Beclin-1 homolog (EcBeclin-1) from orange-spotted grouper (Epinephelus coioides) was identified and its roles in viral infection were investigated. EcBeclin-1 encoded 447amino acids protein with a BH3 domain, a CCD domain and an ECD domain, which shared high identities (97%-82%) with reported Beclin-1 proteins from mammal to fish. Quantitative real-time PCR (qRT-PCR) analysis revealed that EcBeclin-1 was predominantly expressed in brain and muscle of healthy grouper. Using fluorescence microscopy, we found that EcBeclin-1 was co-localized with endoplasmic reticulum (ER) in grouper spleen cells (EAGS). After red-spotted grouper nervous necrosis virus (RGNNV) infection in vitro, EcBeclin-1 transcript was significantly up-regulated, implying that EcBeclin-1 might be involved in viral infection. Furthermore, the in vitro studies of EcBeclin-1 overexpression promoted RGNNV induced autophagy, as well as the expression of coat protein (CP) and RNA-dependent RNA polymerase (RdRp). The overexpression of EcBeclin-1 suppressed the expressions of interferon pathway-related factors, inflammatory-related factors and activities of NF-κB and ISRE. Additionally, EcBeclin-1 could interact with EcBcl-xL in vitro. These data suggest that EcBeclin-1 affect viral replication through modulating IFN and inflammatory responses, as well as virus-induced cell death, which will help us to further explore the immune response of fish during viral infection.