A mechanism that transduces lysosomal damage signals to stress granule formation for cell survival.

Lysosomal damage poses a significant threat to cell survival. Our previous work has reported that lysosomal damage induces stress granule (SG) formation. However, the importance of SG formation in determining cell fate and the precise mechanisms through which lysosomal damage triggers SG formation remains unclear. Here, we show that SG formation is initiated via a novel calcium-dependent pathway and plays a protective role in promoting cell survival in response to lysosomal damage. Mechanistically, we demonstrate that during lysosomal damage, ALIX, a calcium-activated protein, transduces lysosomal damage signals by sensing calcium leakage to induce SG formation by controlling the phosphorylation of eIF2α. ALIX modulates eIF2α phosphorylation by regulating the association between PKR and its activator PACT, with galectin-3 exerting a negative effect on this process. We also found this regulatory event of SG formation occur on damaged lysosomes. Collectively, these investigations reveal novel insights into the precise regulation of SG formation triggered by lysosomal damage, and shed light on the interaction between damaged lysosomes and SGs. Importantly, SG formation is significant for promoting cell survival in the physiological context of lysosomal damage inflicted by SARS-CoV-2 ORF3a, adenovirus infection, Malaria hemozoin, proteopathic tau as well as environmental hazard silica.

Efficacy of ileus tube combined with meglumine diatrizoate in treating postoperative inflammatory bowel obstruction after surgery.

BACKGROUND: Early postoperative inflammatory small bowel obstruction (EPISBO) is easy to be complicated after colorectal cancer surgery. Both intestinal obstruction catheter and meglumine can treat EPISBO. AIM: To investigate the efficacy of an intestinal obstruction tube combined with meglumine diazo in treating EPISBO of colorectal cancer. METHODS: Data from 60 patients with colorectal cancer and intestinal obstruction admitted to the Proctology Department of our hospital from April 2018 to May 2022 were collected and analyzed and divided into three cohorts according to different treatment regimens. Cohort A (n = 20) received a transnasal intestinal obstruction catheter with panumglumine, and cohort B (n = 20) received a transnasal intestinal obstruction catheter with liquid paraffin. Cohort C (n = 20) received oral treatment with meglumine. The clinical efficacy, first exhaust/defecation time, length of hospital stay, gastrointestinal decompression time, relief time of abdominal pain, and relief time of abdominal distension were compared among the three cohorts. The levels of C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), monocyte chemotactic protein-1 (MCP-1), serum albumin, and transferrin were compared among the three cohorts before and after treatment. The occurrence of adverse reactions in the three cohorts was compared. RESULTS: Compared with cohort C, the successful treatment rate of cohort A was significantly higher. There were statistically significant variations in the time of first exhaust/defecation, length of hospital stays, gastrointestinal decompression time, relief time of abdominal pain, and relief time of abdominal distention among the three cohorts. Compared with cohort C, cohort A's first exhaust/defecation time, hospitalization time, gastrointestinal decompression time, abdominal pain relief time, and abdominal distension relief time was reduced (P < 0.05). After treatment, serum CRP, TNF-α, IL-6, and MCP-1 expression levels increased, and serum albumin and serum transferrin levels increased in the three cohorts. The serum albumin level in cohort A was higher than in cohort C. Compared with cohort B and cohort C, the serum transferrin level in cohort A increased (P < 0.05). Compared with cohort C, the total incidence of adverse reactions in cohorts A and B was significantly higher (P < 0.05). The incidence of adverse reactions was similar between cohort A and cohort B. CONCLUSION: Using an ileus tube combined with meglumine diatrizoate can effectively treat postoperative inflammatory ileus obstructions after surgery colorectal cancer and improve prognosis, inflammatory response, and nutritional status.

Comparative analysis of the phenolic contents and antioxidant activities of different parts of two pomegranate (Punica granatum L.) Cultivars: 'Tunisia' and 'Qingpi'.

Pomegranate (Punica granatum L.), with its abundant phenolic substances and strong antioxidant activity, holds significant research and utilization potential across various organs. However, there have been few studies on the phenolic content and antioxidant activity of different parts of pomegranate, especially the placenta. This study investigated the phenolic content and antioxidant activity of fruits, flowers, and leaves of two pomegranate varieties, 'Tunisia' and 'Qingpi', throughout their growth and development. Results indicated significant variations in phenolic content among different organs, with petals exhibiting the highest total polyphenol content (TPC, 49.40 mg GAE/g FW) and total anthocyanin content (TMAC, 1938.54 nmol/g FW). Placenta contained the highest levels of total flavonoids (TFC, 173.58 mg RE/g FW) and punicalagin (109.30 mg/g FW). The peel had the highest content of total flavanols (TFAC, 19.42 mg CE/g FW). Over the course of pomegranate development, total polyphenols, total flavonoids, total flavanols, punicalagin, and antioxidant activity declined in different organs. Antioxidant activity followed the order: fruit > flower > leaf, with the placenta exhibiting the highest antioxidant activity among fruits. Antioxidant activity showed a significant positive correlation with total polyphenols (R2 = 0.77-1.00), total flavonoids (R2 = 0.71-0.99, except tegmens), and punicalagin (R2 = 0.71-1.00). This study provides a comparative analysis of the phenolic content and antioxidant activity in different organs of pomegranate, highlighting the placenta as the primary source of punicalagin. This study provides a theoretical basis for the development and utilization of pomegranate phenolic compounds.

Effects of L-Cysteine and γ-Aminobutyric Acid Treatment on Postharvest Quality and Antioxidant Activity of Loquat Fruit during Storage.

Sichuan is the China's leading producer of loquat, with the largest cultivation area and yield ranked first in China. Loquat is a seasonal fruit highly appreciated by consumers; however, the fruit is prone to browning and lignification after harvest, affecting its storage quality. The effects of L-Cysteine (L-Cys, 0.01, 0.05, 0.1, 0.2%) and γ-aminobutyric acid (GABA, 0.025, 0.05, 0.075, 0.1%) on the sensory quality and antioxidant activity of loquat fruit during cold storage at 4 °C for 35 days and simulated shelf life for 5 days were investigated. The results showed that after 40 days of storage, compared with the control, 0.05% L-Cys and 0.05% GABA treatment of 'Zaozhong No. 6' loquat fruit effectively reduced the weight loss rate, browning index, decay index, respiratory rate, firmness, and lignin content and slowed the decreases in total soluble solids, soluble sugar, titratable acidityand vitamin C contents. The application of 0.05% L-Cys and 0.05% GABA significantly increased the contents of total phenols, total flavonoids, flavanols, and carotenoids; delayed the increase of relative electric conductivity, MDA, POD, and PPO activities; and significantly enhanced the activities of SOD and CAT, DPPH free radical scavenging ability, and FRAP, thereby improving antioxidant capacity. In summary, 0.05% L-Cys and 0.05% GABA treatment promotes the quality of loquat fruit after 40 days of storage, and significantly enhances antioxidant capacity, thus delaying senescence after harvest.

An inducible hACE2 transgenic mouse model recapitulates SARS-CoV-2 infection and pathogenesis in vivo.

The classical manifestation of COVID-19 is pulmonary infection. After host cell entry via human angiotensin-converting enzyme II (hACE2), the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus can infect pulmonary epithelial cells, especially the AT2 (alveolar type II) cells that are crucial for maintaining normal lung function. However, previous hACE2 transgenic models have failed to specifically and efficiently target the cell types that express hACE2 in humans, especially AT2 cells. In this study, we report an inducible, transgenic hACE2 mouse line and showcase three examples for specifically expressing hACE2 in three different lung epithelial cells, including AT2 cells, club cells, and ciliated cells. Moreover, all these mice models develop severe pneumonia after SARS-CoV-2 infection. This study demonstrates that the hACE2 model can be used to precisely study any cell type of interest with regard to COVID-19-related pathologies.

High Levels of Extracellular Potassium Can Delay Myxoma Virus Replication by Preventing Release of Virions from the Endosomes.

Potassium (K+) is one of the most abundant cations in the human body. Under normal conditions, the vast majority of K+ is found within cells, and the extracellular [K+] is tightly regulated to within 3.0 to 5.0 mM. However, it has recently been shown that high levels of localized necrosis can increase the extracellular concentration of K+ to above 50 mM. This raises the possibility that elevated extracellular K+ might influence a variety of biological processes that occur within regions of necrotic tissue. For example, K+ has been shown to play a central role in the replication cycles of numerous viral families, and in cases of lytic infection, localized regions containing large numbers of necrotic cells can be formed. Here, we show that the replication of the model poxvirus myxoma virus (MYXV) is delayed by elevated levels of extracellular K+. These increased K+ concentrations alter the cellular endocytic pathway, leading to increased phagocytosis but a loss of endosomal/lysosomal segregation. This slows the release of myxoma virus particles from the endosomes, resulting in delays in genome synthesis and infectious particle formation as well as reduced viral spread. Additionally, mathematical modeling predicts that the extracellular K+ concentrations required to impact myxoma virus replication can be reached in viral lesions under a variety of conditions. Taken together, these data suggest that the extracellular [K+] plays a role in determining the outcomes of myxoma infection and that this effect could be physiologically relevant during pathogenic infection. IMPORTANCE Intracellular K+ homeostasis has been shown to play a major role in the replication of numerous viral families. However, the potential impact of altered extracellular K+ concentrations is less well understood. Our work demonstrates that increased concentrations of extracellular K+ can delay the replication cycle of the model poxvirus MYXV by inhibiting virion release from the endosomes. Additionally, mathematical modeling predicts that the levels of extracellular K+ required to impact MYXV replication can likely be reached during pathogenic infection. These results suggest that localized viral infection can alter K+ homeostasis and that these alterations might directly affect viral pathogenesis.

Peptide-Based HIV Entry Inhibitors.

The development of peptide-based HIV entry inhibitors has made an important contribution to the stock of anti-HIV drugs. In particular, the peptide-based anti-HIV drugs enfuvirtide and albuvirtide were approved for clinical use by the U.S. FDA and CFDA in 2003 and 2018, respectively. Peptide-based HIV entry inhibitors exert antiviral activity by targeting the early stage of viral infection, i.e., binding of a viral surface protein to the receptor(s) on the host cell and the subsequent fusion between the viral and host cell membranes. Therefore, they are particularly useful for HIV-infected patients who have failed to respond to the highly active antiretroviral drugs (ARD) targeting the late stage of HIV replication, such as reverse transcriptase inhibitors and protease inhibitors. In this chapter, we will focus on the past, current, and future trends in research and development of peptide-based HIV entry inhibitors.

A Five-Helix-Based SARS-CoV-2 Fusion Inhibitor Targeting Heptad Repeat 2 Domain against SARS-CoV-2 and Its Variants of Concern.

The prolonged duration of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic has resulted in the continuous emergence of variants of concern (VOC, e.g., Omicron) and variants of interest (VOI, e.g., Lambda). These variants have challenged the protective efficacy of current COVID-19 vaccines, thus calling for the development of novel therapeutics against SARS-CoV-2 and its VOCs. Here, we constructed a novel fusion inhibitor-based recombinant protein, denoted as 5-Helix, consisting of three heptad repeat 1 (HR1) and two heptad repeat 2 (HR2) fragments. The 5-Helix interacted with the HR2 domain of the viral S2 subunit, the most conserved region in spike (S) protein, to block homologous six-helix bundle (6-HB) formation between viral HR1 and HR2 domains and, hence, viral S-mediated cell-cell fusion. The 5-Helix potently inhibited infection by pseudotyped SARS-CoV-2 and its VOCs, including Delta and Omicron variants. The 5-Helix also inhibited infection by authentic SARS-CoV-2 wild-type (nCoV-SH01) strain and its Delta variant. Collectively, our findings suggest that 5-Helix can be further developed as either a therapeutic or prophylactic to treat and prevent infection by SARS-CoV-2 and its variants.

Co3O4@TiO2@Y2O3 nanocomposites for a highly sensitive CO gas sensor and quantitative analysis.

In order to predict the early failure of organic insulator, Co3O4@TiO2@Y2O3 nanocomposites was prepared and characterized (XRD, SEM, EDS, FTIR, UV-vis-NIR, XPS) to detect decomposition CO gas. A simple experimental platform was built to verify the excellent adsorption, stability, selectivity and repeatability of the composite. Then, the mechanism of adsorption enhancement was analyzed by heterojunction. Aiming at 170 sets of gas sensing data sets, Successive Projections Algorithm (SPA) was used to extract data features, and grey wolf optimization vector machine regression (GWO-SVR) model was established to predict carbon monoxide concentration. The correlation coefficient (RP), root mean square error (RMSEP) and calculation time of prediction set were 99.3025%, 0.0418 and 1.47 s, respectively. Therefore, the combination of the superior properties of a composite sensitive material and the small sample quantitative prediction model is a promising method for gas sensors in the future.

Viral Entry Inhibitors Targeting Six-Helical Bundle Core against Highly Pathogenic Enveloped Viruses with Class I Fusion Proteins.

Type Ⅰ enveloped viruses bind to cell receptors through surface glycoproteins to initiate infection or undergo receptor-mediated endocytosis and initiate membrane fusion in the acidic environment of endocytic compartments, releasing genetic material into the cell. In the process of membrane fusion, envelope protein exposes fusion peptide, followed by an insertion into the cell membrane or endosomal membrane. Further conformational changes ensue in which the type 1 envelope protein forms a typical six-helix bundle structure, shortening the distance between viral and cell membranes so that fusion can occur. Entry inhibitors targeting viral envelope proteins, or host factors, are effective antiviral agents and have been widely studied. Some have been used clinically, such as T20 and Maraviroc for human immunodeficiency virus 1 (HIV-1) or Myrcludex B for hepatitis D virus (HDV). This review focuses on entry inhibitors that target the six-helical bundle core against highly pathogenic enveloped viruses with class I fusion proteins, including retroviruses, coronaviruses, influenza A viruses, paramyxoviruses, and filoviruses.

Knowledge about Human Papillomavirus and Cervical Cancer Prevention among Intern Nurses.

OBJECTIVE: Intern nurses will play an important role in the use of vaccination to prevent cervical cancer. This study assesses the knowledge about human papillomavirus (HPV) infection and cervical cancer prevention among intern nurses. METHODS: We developed a questionnaire to investigate intern nurses' knowledge about HPV infection and cervical cancer prevention. Participants included 323 intern nurses from eight schools. RESULTS: The effective response rate was 79.8%. Some (7.0%) knew that early-stage cervical cancer is commonly asymptomatic. Only 9.7% knew that infection is generally asymptomatic and 20.5% knew that vaccination has no major side effects. There were differences in gender, age, school type, and place of residence for several questions. CONCLUSIONS: This study indicates a low level of knowledge about HPV infection and cervical cancer prevention among intern nurses. Our findings highlight the need for more education in this topic to increase the knowledge of intern nurses.

An amphipathic peptide targeting the gp41 cytoplasmic tail kills HIV-1 virions and infected cells.

HIV-associated morbidity and mortality have markedly declined because of combinational antiretroviral therapy, but HIV readily mutates to develop drug resistance. Developing antivirals against previously undefined targets is essential to treat existing drug-resistant HIV strains. Some peptides derived from HIV-1 envelope glycoprotein (Env, gp120-gp41) have been shown to be effective in inhibiting HIV-1 infection. Therefore, we screened a peptide library from HIV-1 Env and identified a peptide from the cytoplasmic region, designated F9170, able to effectively inactivate HIV-1 virions and induce necrosis of HIV-1-infected cells, and reactivated latently infected cells. F9170 specifically targeted the conserved cytoplasmic tail of HIV-1 Env and effectively disrupted the integrity of the viral membrane. Short-term monoadministration of F9170 controlled viral loads to below the limit of detection in chronically SHIV-infected macaques. F9170 can enter the brain and lymph nodes, anatomic reservoirs for HIV latency. Therefore, F9170 shows promise as a drug candidate for HIV treatment.

Design and Biological Evaluation of m-Xylene Thioether-Stapled Short Helical Peptides Targeting the HIV-1 gp41 Hexameric Coiled-Coil Fusion Complex.

Short peptide-based inhibition of fusion remains an attractive goal in antihuman immunodeficiency virus (HIV) research based on its potential for the development of technically and economically desirable antiviral agents. Herein, we report the use of the dithiol bisalkylation reaction to generate a series of m-xylene thioether-stapled 22-residue α-helical peptides that have been identified as fusion inhibitors targeting HIV-1 glycoprotein 41 (gp41). The peptide sequence is based on the helix-zone binding domain of the gp41 C-terminal heptad repeat region. We found that one of these stapled peptides, named hCS6ERE, showed promising inhibitory potency against HIV-1 Env-mediated cell-cell fusion and viral replication at a level comparable to the clinically used 36-mer peptide T20. Furthermore, combining hCS6ERE with a fusion inhibitor having a different target site, such as HP23, produced synergistic anti-HIV-1 activity. Collectively, our study offers new insight into the design of anti-HIV peptides with short sequences.

A pair of new enantiomers of xanthones from the stems and leaves of Cratoxylum cochinchinense.

BACKGROUND: The simple and caged xanthones from Clusiaceae showed significant antineoplastic activity. This study aims to identify structural diverse xanthones and search for novel antitumor natural products from this family plants. METHODS: The structures of new compounds 1a and 1b were elucidated mainly through comprehensive NMR and MS spectroscopic data, and their absolute configurations were determined by the comparison of the experimental and calculated electronic circular dichroism. RESULTS: A pair of new xanthone enantiomers, (+)- and (-)-cracochinxanthone A (1a and 1b), along with thirty known analogues (2-31), were isolated from extracts of the stems and leaves of C. cochinchinense. Preliminary biological assay of some isolates against HL-60, PC-3, and MDA-MB-231 cancer cell lines. CONCLUSION: Some isolated xanthones exhibited high sensitivity against three human malignant cell lines and the structure-activity relationship study showed that the prenyl and geranyl units may play an important role in antitumor activity.

Potent MERS-CoV Fusion Inhibitory Peptides Identified from HR2 Domain in Spike Protein of Bat Coronavirus HKU4.

The Middle East respiratory syndrome coronavirus (MERS-CoV) emerged in 2012 and caused continual outbreaks worldwide with high mortality. However, no effective anti-MERS-CoV drug is currently available. Recently, numerous evolutionary studies have suggested that MERS-CoV originated from bat coronavirus (BatCoV). We herein reported that three peptides derived from the HR2 region in spike protein of BatCoV HKU4, including HKU4-HR2P1, HKU4-HR2P2 and HKU4-HR2P3, could bind the MERS-CoV HR1-derived peptide to form a six-helix bundle (6-HB) with high stability. Moreover, these peptides, particularly HKU4-HR2P2 and HKU4-HR2P3, exhibited potent inhibitory activity against MERS-CoV S-mediated cell⁻cell fusion and viral infection, suggesting that these HKU4 HR2-derived peptides could be candidates for futher development as antiviral agents against MERS-CoV infection.

A Ragulator-BORC interaction controls lysosome positioning in response to amino acid availability.

Lysosomes play key roles in the cellular response to amino acid availability. Depletion of amino acids from the medium turns off a signaling pathway involving the Ragulator complex and the Rag guanosine triphosphatases (GTPases), causing release of the inactive mammalian target of rapamycin complex 1 (mTORC1) serine/threonine kinase from the lysosomal membrane. Decreased phosphorylation of mTORC1 substrates inhibits protein synthesis while activating autophagy. Amino acid depletion also causes clustering of lysosomes in the juxtanuclear area of the cell, but the mechanisms responsible for this phenomenon are poorly understood. Herein we show that Ragulator directly interacts with BLOC-1-related complex (BORC), a multi-subunit complex previously found to promote lysosome dispersal through coupling to the small GTPase Arl8 and the kinesins KIF1B and KIF5B. Interaction with Ragulator exerts a negative regulatory effect on BORC that is independent of mTORC1 activity. Amino acid depletion strengthens this interaction, explaining the redistribution of lysosomes to the juxtanuclear area. These findings thus demonstrate that amino acid availability controls lysosome positioning through Ragulator-dependent, but mTORC1-independent, modulation of BORC.

BORC Functions Upstream of Kinesins 1 and 3 to Coordinate Regional Movement of Lysosomes along Different Microtubule Tracks.

The multiple functions of lysosomes are critically dependent on their ability to undergo bidirectional movement along microtubules between the center and the periphery of the cell. Centrifugal and centripetal movement of lysosomes is mediated by kinesin and dynein motors, respectively. We recently described a multi-subunit complex named BORC that recruits the small GTPase Arl8 to lysosomes to promote their kinesin-dependent movement toward the cell periphery. Here, we show that BORC and Arl8 function upstream of two structurally distinct kinesin types: kinesin-1 (KIF5B) and kinesin-3 (KIF1Bß and KIF1A). Remarkably, KIF5B preferentially moves lysosomes on perinuclear tracks enriched in acetylated α-tubulin, whereas KIF1Bß and KIF1A drive lysosome movement on more rectilinear, peripheral tracks enriched in tyrosinated α-tubulin. These findings establish BORC as a master regulator of lysosome positioning through coupling to different kinesins and microtubule tracks. Common regulation by BORC enables coordinate control of lysosome movement in different regions of the cell.

Mechanisms and functions of lysosome positioning.

Lysosomes have been classically considered terminal degradative organelles, but in recent years they have been found to participate in many other cellular processes, including killing of intracellular pathogens, antigen presentation, plasma membrane repair, cell adhesion and migration, tumor invasion and metastasis, apoptotic cell death, metabolic signaling and gene regulation. In addition, lysosome dysfunction has been shown to underlie not only rare lysosome storage disorders but also more common diseases, such as cancer and neurodegeneration. The involvement of lysosomes in most of these processes is now known to depend on the ability of lysosomes to move throughout the cytoplasm. Here, we review recent findings on the mechanisms that mediate the motility and positioning of lysosomes, and the importance of lysosome dynamics for cell physiology and pathology.

The identification of novel Mycobacterium tuberculosis DHFR inhibitors and the investigation of their binding preferences by using molecular modelling.

It is an urgent need to develop new drugs for Mycobacterium tuberculosis (Mtb), and the enzyme, dihydrofolate reductase (DHFR) is a recognised drug target. The crystal structures of methotrexate binding to mt- and h-DHFR separately indicate that the glycerol (GOL) binding site is likely to be critical for the function of mt-DHFR selective inhibitors. We have used in silico methods to screen NCI small molecule database and a group of related compounds were obtained that inhibit mt-DHFR activity and showed bactericidal effects against a test Mtb strain. The binding poses were then analysed and the influence of GOL binding site was studied by using molecular modelling. By comparing the chemical structures, 4 compounds that might be able to occupy the GOL binding site were identified. However, these compounds contain large hydrophobic side chains. As the GOL binding site is more hydrophilic, molecular modelling indicated that these compounds were failed to occupy the GOL site. The most potent inhibitor (compound 6) demonstrated limited selectivity for mt-DHFR, but did contain a novel central core (7H-pyrrolo[3,2-f]quinazoline-1,3-diamine), which may significantly expand the chemical space of novel mt-DHFR inhibitors. Collectively, these observations will inform future medicinal chemistry efforts to improve the selectivity of compounds against mt-DHFR.