Spatiotemporal analysis of ratiometric biosensors in live multicellular spheroids using SPoRTS

Here, we describe SPoRTS, an open-source workflow for high-throughput spatiotemporal image analysis of fluorescence-based ratiometric biosensors in living spheroids. To achieve this, we have implemented a fully automated algorithm for the acquisition of line intensity profile data, ultimately enabling semi-quantitative measurement of biosensor activity as a function of distance from the center of the spheroid. We demonstrate the functionality of SPoRTS via spatial analysis of live spheroids expressing a ratiometric biosensor based on the fluorescent, ubiquitin-based cell-cycle indicator (FUCCI) system, which identifies mitotic cells. We compare this FUCCI-based SPoRTS analysis with spatially quantified immunostaining for proliferation markers, finding that the results are strongly correlated.

Targeting NLRC5 in cardiomyocytes protects postinfarction cardiac injury by enhancing autophagy flux through the CAVIN1/CAV1 axis

NOD-like receptor (NLR) family proteins are implicated in various cardiovascular diseases. However, the precise role of NLRC5, the largest member of this family, in myocardial infarction (MI) remains poorly understood. This study reveals that NLRC5 is upregulated in the hearts of both patients with MI and MI mice. Silencing NLRC5 in cardiomyocytes impairs cardiac repair and functional recovery, while its overexpression enhances these processes. Furthermore, NLRC5 promotes autophagy in cardiomyocytes, and its protective effects are diminished upon autophagy inhibition. Mechanistically, NLRC5 interacts with CAVIN1, facilitating its degradation and subsequent downregulation of CAV1, which in turn increases the expression of the ATG12-ATG5 complex to stimulate autophagy. Conversely, CAV1 overexpression partially suppresses autophagy and attenuates the improvements in cardiac function observed in NLRC5-overexpressing MI hearts. This study highlights the critical regulatory role of NLRC5 in modulating cardiomyocyte autophagy flux, suggesting that NLRC5 activation may represent a promising therapeutic strategy for MI.

Insulin-Like Growth Factor 2 Secreted from Mesenchymal Stem Cells with High Glutathione Levels Alleviates Osteoarthritis via Paracrine Rejuvenation of Senescent Chondrocytes

Senescent chondrocytes, which are increased in osteoarthritic (OA) cartilage, promote cartilage defects and the senescent knee microenvironment by inducing senescence to surrounding normal chondrocytes by secreting senescence-associated secretory proteins. Many studies have used mesenchymal stem cells (MSCs) to treat OA, but MSC treatment remains challenging for clinical application owing to MSC quality control, engraftment, and fibrocartilage regeneration. Here, rather than relying on the direct regeneration of MSCs, we present a novel strategy to suppress OA by MSC-mediated senescent chondrocyte targeting via the paracrine activity of MSCs, thereby improving the knee microenvironment. First, to enable quality control of umbilical cord MSCs, priming MSCs by supplementing human platelet lysate (hPL) greatly enhanced MSC functions by increasing cellular glutathione levels throughout serial passaging. Intra-articular injection of primed MSCs successfully suppressed OA progression and senescent chondrocyte accumulation without direct regeneration. Indirect coculture with primed MSCs using transwell ameliorated the senescence phenotypes in OA chondrocytes, suggesting paracrine rejuvenation. Based on secretome analysis, we identified insulin-like growth factor 2 (IGF2) as a key component that induces paracrine rejuvenation by primed MSCs. The rejuvenation effects of IGF2 act through autophagy activation through the up-regulation of autophagy-related gene expression and autophagic flux. To cross-validate the effects of secreted IGF2 in vivo, knockdown of IGF2 in primed MSCs substantially abolished its therapeutic efficacy in a rabbit OA model. Collectively, these findings demonstrate that hPL supplementation enables MSC quality control by increasing MSC glutathione levels. The therapeutic mechanism of primed MSCs was secreted IGF2, which induces paracrine rejuvenation of senescent OA chondrocytes by activating autophagy.

Maternal hyperglycemia and postnatal high-fat diet impair metabolic regulation and autophagy response in the liver of adult female rats

This study aimed to investigate the mechanisms by which the association between maternal hyperglycemia and postnatal high-fat diet (HFD) exposure compromises metabolic parameters and hepatic autophagy in adult female pups. For this, Sprague Dawley rats, female pups from nondiabetic (control = FC) or diabetic (FD) mothers, were fed a standard diet (SD) or HFD from weaning until adulthood (n minimum = 5 rats/group): FC/SD, FC/HFD, FD/SD, and FD/HFD. In adulthood, these rats were tested with the oral glucose tolerance test, euthanized, and serum biochemistry parameters were analyzed. Liver samples were collected to evaluate cytokines, redox status, and protein expression autophagy and apoptosis markers. Histomorphometric analyses and an assessment of lipofuscin accumulation were also performed to reflect incomplete autolysosomal digestion. The FC/HFD, FD/SD, and FD/HFD groups showed glucose intolerance and an increased number of hepatocytes. Furthermore, FD/SD and FD/HFD rats showed hyperlipidemia and insulin resistance. Adaptations in hepatic redox pathways were observed in the FD/SD group with increased antioxidant defense marker activity. The FD/SD group also exhibited increased autophagy protein expression, such as p-AMPK, LC3-II/LC3-I, and p62/SQSTM1, lipofuscin accumulation, and caspase-3 activation. After exposure to HFD, the adult female pups of diabetic rats had a reduced p-AMPK and LC3-II/LC3-I ratio, the presence of steatosis, oxidative stress, and inflammation. The reduction of autophagy, stimulated by HFD, may be of vital importance for the susceptibility to metabolic dysfunction-associated fatty liver disease induced by maternal diabetes.

Adaptation of Natural Killer Cells to Hypoxia: A Review of the Transcriptional, Translational, and Metabolic Processes

As important innate immune cells, natural killer (NK) cells play an essential role in resisting pathogen invasion and eliminating transformed cells. However, the hypoxic microenvironment caused by disease conditions is an important physicochemical factor that impairs NK cell function. With the increasing prominence of NK cells in immunotherapy, there has been a surge of interest in developing biological means through which NK cells may overcome the inhibition caused by hypoxia in disease conditions. Although the effects of hypoxic conditions in shaping the functions of NK cells have been increasingly recognized and investigated, reviews have been scantly. A comprehensive understanding of how NK cells adapt to hypoxia can provide valuable insights into how the functional capacity of NK cells may be restored. This review focuses on the functional alterations of NK cells in response to hypoxia. It delineates the mechanisms by which NK cells adapt to hypoxia at the transcriptional, metabolic, translational levels. Furthermore, given the complexity of the hypoxic microenvironment, we also elucidated the effects of key hypoxic metabolites on NK cells. Finally, this review discusses the current clinical therapies derived from targeting hypoxic NK cells. The study of NK cell adaptation to hypoxia has yielded new insights into immunotherapy. These insights may lead to development of novel strategies to improve the treatment of infectious diseases and cancer.

Irisin alleviates hepatic steatosis by activating the autophagic SIRT3 pathway

BACKGROUND

Disruption of hepatic lipid homeostasis leads to excessive hepatic triglyceride accumulation and the development of metabolic dysfunction-associated steatotic liver disease (MASLD). Autophagy, a critical process in liver lipid metabolism, is impaired in MASLD pathogenesis. Irisin, a skeletal muscle-driven myokine, regulates lipid metabolism, but its impact on hepatic lipid metabolism is not well understood. Here, we aimed to explore the role of irisin in hepatic steatosis and the underlying mechanisms involved.

METHODS

A high-fat diet (HFD)-induced MASLD mouse model was used, and the recombinant irisin protein, herein referred to as "Irisin", was intraperitoneally administered for 4 weeks to evaluate the effects of irisin on hepatic lipid accumulation. Liver tissues were stained with Oil red O (ORO), and triglyceride (TG) and total cholesterol (TC) contents were measured in serum and liver homogenates. The expression of the autophagosome marker microtubule-associated protein 1 light chain 3 (LC3), the autophagy receptor protein sequestosome-1 (SQSTM1/p62), autophagy initiation complex unc-51-like kinase 1 (ULK1) and the lysosomal functional protein cathepsin B was measured via Western blotting, and the expression of the transcription factor EB (TFEB) was analyzed via immunofluorescence to explore autophagic changes. The effect of irisin on autophagic flux was further evaluated in palmitic acid-induced HepG2 cells by measuring autophagic degradation with chloroquine (CQ), and analyzing the colocalization of LC3 and lysosome-associated protein 1 (LAMP1). The possible mechanism was examined by measuring the expression of the autophagic sirtuin 3 (SIRT3) pathway and further validated using overexpression of SIRT3 with plasmid transfection or siRNA-mediated knockdown. Student's t-test was utilized for statistical analysis.

RESULTS

Irisin significantly reduces hepatic lipid accumulation in mice fed with HFD, accompanied by enhanced hepatocyte autophagy and upregulation of the SIRT3 pathway. In HepG2 cells, Irisin attenuated palmitic acid-induced lipid accumulation, which was partially dependent on SIRT3 levels. Mechanistically, Irisin treatment upregulated SIRT3 and phosphorylated AMP-activated protein kinase (AMPK), inhibited mammalian target of rapamycin (mTOR) activity, promoted TFEB nucleus translocation, increased cathepsin B expression, enhanced autophagic degradation, and alleviated hepatic steatosis. No significant changes in phosphorylation of ULK1 in the hepatocytes were observed. However, when siRNA was used to knock down SIRT3, the changes of those protein were partially reversed, and hepatic steatosis was further exacerbated.

CONCLUSIONS

Our findings highlight irisin as a potential therapeutic for hepatic steatosis by modulating autophagy and lipid metabolism, potentially providing a novel therapeutic target for the management of MASLD. Further research is needed to elucidate the underlying mechanisms and explore the potential clinical applications of this approach in the treatment of MASLD.

RGD hydrogel-loaded ADSC extracellular vesicles mitigate uranium-induced renal injury via TLR4/NF-κB pathway inhibition

BACKGROUND

Uranium-induced kidney damage represents a major health concern due to its toxic effects, including mitochondrial dysfunction and inflammation. Mitochondrial DNA (mtDNA)-mediated pyroptosis is a critical pathway in the pathogenesis of renal injury. The toll-like receptor 4 / nuclear factor-kappa B (TLR4/NF-κB) signaling pathway plays a pivotal role in this process. Recent studies have shown that extracellular vesicles derived from adipose-derived stem cells (ADSCs-EVs) possess therapeutic potential due to their anti-inflammatory and regenerative properties. Incorporating ADSCs-EVs into arginine-glycine-aspartate (RGD), hydrogels may enhance their stability and therapeutic efficacy in vivo. This study aims explore the molecular mechanism by which RGD hydrogel-loaded ADSCs-EVs modulate mtDNA-mediated pyroptosis by suppressing the TLR4/NF-κB signaling pathway to alleviate uranium-induced kidney injury.

RESULTS

Repairing mitochondrial dysfunction was found to mitigate mtDNA leakage, thereby inhibiting renal pyroptosis. ADSCs-EVs alleviated uranium-induced renal cell damage by suppressing the TLR4/NF-κB signaling pathway. In vivo animal experiments confirmed that RGD hydrogel-loaded ADSCs-EVs enhanced their stability in the body and improved their therapeutic efficacy against kidney injury.

CONCLUSION

Our findings reveal that RGD hydrogel-loaded ADSCs-EVs effectively inhibit the TLR4/NF-κB signaling pathway, preventing mtDNA-mediated pyroptosis and alleviating uranium-induced kidney damage. This elucidation provides a novel strategy for utilizing RGD hydrogel-loaded ADSCs-EVs in treating kidney injury.

Retinoic Acid Promotes Neuronal Differentiation While Increasing Proteins and Organelles Related to Autophagy

Retinoic acid (RA) is commonly used to differentiate SH-SY5Y neuroblastoma cells. This effect is sustained by a specific modulation of gene transcription, leading to marked changes in cellular proteins. In this scenario, autophagy may be pivotal in balancing protein synthesis and degradation. The present study analyzes whether some autophagy-related proteins and organelles are modified during RA-induced differentiation of SH-SY5Y cells. RA-induced effects were compared to those induced by starvation. SH-SY5Y cells were treated with a single dose of 10 µM RA or grown in starvation, for 3 days or 7 days. After treatments, cells were analyzed at light microscopy and transmission electron microscopy to assess cell morphology and immunostaining for specific markers (nestin, βIII-tubulin, NeuN) and some autophagy-related proteins (Beclin 1, LC3). We found that both RA and starvation differentiate SH-SY5Y cells. Specifically, cell differentiation was concomitant with an increase in autophagy proteins and autophagy-related organelles. However, the effects of a single dose of 10 μM RA persist for at least 7 days, while prolonged starvation produces cell degeneration and cell loss. Remarkably, the effects of RA are modulated in the presence of autophagy inhibitors or stimulators. The present data indicate that RA-induced differentiation is concomitant with an increased autophagy.

Impairment of proteasome-associated deubiquitinating enzyme Uchl5/UBH-4 affects autophagy

The autophagy-lysosomal pathway (ALP) and the ubiquitin-proteasome system (UPS) are the two major intracellular proteolytic systems that mediate protein turnover in eukaryotes. Although a crosstalk exists between these two systems, it is still unclear how UPS and ALP interact in vivo. Here, we investigated how impaired function of the proteasome-associated deubiquitinating enzyme (DUB) Uchl5/UBH-4 affects autophagy in human cells and in a multicellular organism. We show that downregulation of Uchl5 by siRNA reduces autophagy by partially blocking the fusion of autophagosomes with the lysosomes in HeLa cells, which is similar to a previously reported role of the proteasome-associated DUB Usp14 on autophagy. However, exposure of Caenorhabditis elegans to ubh-4 or usp-14 RNAi, or to their pharmacological inhibitors, results in diverse effects on numbers of autophagosomes and autolysosomes, without blocking the lysosomal fusion, in the intestine, hypodermal seam cells and the pharynx. Our results reveal that impairment of Uchl5/UBH-4 and Usp14 affects autophagy in a tissue context manner. A deeper insight into the interplay between UPS and ALP in various tissues in vivo has the potential to promote development of therapeutic approaches for disorders associated with proteostasis dysfunction.

COVID-19 worsens quality of life in elderly heart failure patients: a clinical study

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has significantly worsened the health and quality of life of vulnerable populations, particularly elderly patients with heart failure. This study aimed to assess the effect of COVID-19 infection on the quality of life in elderly patients with heart failure during the pandemic.

METHODS

This retrospective case-control study included elderly heart failure patients admitted to the Second People's Hospital of Lanzhou between December 2022 and December 2023, all of whom were diagnosed during the ongoing COVID-19 pandemic. All patients underwent COVID-19 nucleic acid testing upon admission. Among the 96 heart failure patients who tested positive for COVID-19 and the 68 who tested negative, multiple validated instruments were used to assess both physical and mental health quality of life. These instruments included the Minnesota Living with Heart Failure Questionnaire (MLHFQ), 36-Item Short Form Health Survey physical component summary score (SF-36 PCS), 6-Minute Walking Test (6MWT), Geriatric Depression Scale-15 (GDS-15), Self-Rating Anxiety Scale (SAS) Total, Pittsburgh Sleep Quality Index (PSQI), Mini Nutritional Assessment-Short Form (MNA-SF), and the Fatigue, Resistance, Ambulation, Illness, and Loss of weight (FRAIL) Scale.

RESULTS

Heart failure patients who tested positive for COVID-19 exhibited significantly lower blood pressure, SF-36 scores, and 6MWT distances compared to those who tested negative (P<0.05). Additionally, the COVID-19-positive group had higher MLHFQ scores, older average age, a greater proportion of patients in NYHA class III-IV, more frequent electrolyte imbalances, elevated D-dimer, C-reactive protein (CRP), and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels, and longer hospital stays (P<0.05). These patients also exhibited higher levels of anxiety (SAS total), poorer sleep quality (PSQI), and greater frailty (FRAIL Scale) compared to their COVID-19-negative counterparts (P<0.05). In addition, heart failure patients with COVID-19 infection reported more severe symptoms of dyspnea and fatigue (P<0.05). Both age and COVID-19 infection were identified as significant factors negatively affecting the quality of life in this patient population.

CONCLUSION

COVID-19 infection significantly exacerbates the decline in quality of life in elderly patients with heart failure. This highlights the urgent need for strengthened, comprehensive treatment and targeted mental health support for this vulnerable group.

Echocardiographic Left Ventricular Function in the Third Year After COVID-19 Hospitalization: A Follow-Up Pilot Study in South-East of Romania

Background and Objectives: Cardiac involvement in COVID-19 has been confirmed during the acute stage of the infection. However, the prevalence and spectrum of post-infectious cardiac dysfunction remain incompletely clarified. The objective of our study was to evaluate the frequency of echocardiographic changes 2 years after hospitalization for moderate and severe COVID-19 in patients with no previously known cardiac pathology. Material and Methods: We conducted a retrospective cohort study analyzing severity markers of COVID-19 infection and echocardiographic parameters assessed ≥2 years after the acute illness, based on recent guideline recommended algorithm for echocardiographic diagnostic of left ventricular (LV) dysfunction. Results: The study included 50 Caucasian patients, 60% male, 54% aged < 65 years, and 32% with severe forms of the disease. The primary comorbidities were hypertension, obesity, and diabetes. COVID-19 severity correlated with the computed tomography (CT) lung lesion score and a neutrophil-to-lymphocyte ratio >6 but was not associated with post-COVID-19 echocardiographic changes. Left ventricular ejection fraction (LVEF) was reduced in only 18% of cases, but global longitudinal strain (GLS) impairment was observed in 46% of patients, contributing to the LV systolic subclinical dysfunction in 61%. Impaired LV diastolic disfunction with normal pressure filling was present in 30.61% of cases and with elevated pressure 10.2%. Conclusions: COVID-19 is an independent predictive factor for GLS impairment, which can indicate myocardial contractile dysfunction, even in patients with asymptomatic heart disease. This underscores the importance of regular echocardiographic monitoring for patients recovering from moderate to severe COVID-19.

Visualizing bulk autophagy in vivo by tagging endogenous LC3B

Macroautophagy/autophagy plays a crucial role in maintaining cellular and organismal health, making the measurement of autophagy flux in vivo essential for its study. Current tools often depend on the overexpression of autophagy probes. In this study, we developed a knock-in mouse model, termed tfLC3-KI, by inserting a tandem fluorescent tag coding sequence into the native Map1lc3b gene locus. We found that tfLC3-KI mice exhibit optimal expression of mRFP-eGFP-LC3B, allowing for convenient measurement of autophagic structures and flux at single-cell resolution, both in vivo and in primary cell cultures. Additionally, we compared autophagy in neurons and glial cells across various brain regions between tfLC3-KI mice and CAG-tfLC3 mice, the latter overexpressing the probe under the strong CMV promoter. Finally, we used tfLC3-KI mice to map the spatial and temporal dynamics of basal autophagy activity in the reproductive system. Our findings highlight the value of the tfLC3-KI mouse model for investigating autophagy flux in vivo and demonstrate the feasibility of tagging endogenous proteins to visualize autophagic structures and flux in both bulk and selective autophagy research in vivo.Abbreviation: BafA1: bafilomycin A1; CQ: chloroquine; EBSS: Earle's balanced salt solution; Es: elongating spermatids; HPF: hippocampalformation; HY: hypothalamus; LCs: leydig cells; OLF: olfactory areas; PepA: pepstatin A; Rs: round spermatids; SCs: sertoli cells; Spc: spermatocytes; Spg: spermatogonia; tfLC3: tandem fluorescently tagged mRFP-eGFP-LC3; TH: thalamus.

Plant-derived exosome-like nanoparticles in tissue repair and regeneration

This article reviews plant-derived exosome-like nanoparticles (ELNs), and highlights their potential in regenerative medicine. Various extraction techniques, including ultracentrifugation and ultrafiltration, and their impact on ELN purity and yield were discussed. Characterization methods such as microscopy and particle analysis are found to play crucial roles in defining ELN properties. This review is focused on exploring the therapeutic potential of ELNs in tissue repair, immune regulation, and antioxidant activities. Further research and optimization methods for extraction of ELNs to realize clinical potential applications are necessary.

MAP1LC3C repression reduces CIITA- and HLA class II expression in non-small cell lung cancer

In the last decade, advancements in understanding the genetic landscape of lung squamous cell carcinoma (LUSC) have significantly impacted therapy development. Immune checkpoint inhibitors (ICI) have shown great promise, improving overall and progression-free survival in approximately 25% of the patients. However, challenges remain, such as the lack of predictive biomarkers, difficulties in patient stratification, and identifying mechanisms that cancers use to become immune-resistant ("immune-cold"). Analysis of TCGA datasets reveals reduced MAP1LC3C expression in cancer. Further analysis indicates that low MAP1LC3C is associated with reduced CIITA and HLA expression and with decreased immune cell infiltration. In tumor cells, silencing MAP1LC3C inhibits CIITA expression and suppresses HLA class II production. These findings suggest that cancer cells are selected for low MAP1LC3C expression to evade efficient immune responses.

Hypoxia Regulates the Proliferation and Apoptosis of Coronary Artery Smooth Muscle Cells Through HIF-1α Mediated Autophagy in Yak

Cell proliferation and migration mediated by hypoxia-inducible factor-1α (HIF-1α) are important processes of hypoxic cardiac vascular remodeling. HIF-1α also regulates the physiological hypoxic adaptation of the coronary artery in the yak heart, but the potential mechanism remains to be completely elucidated. In this study, coronary artery proliferation increased with age and hypoxia adaptation time. In vitro analysis showed that hypoxia can promote the proliferation of coronary vascular smooth muscle cells (CASMCs). Meanwhile, HIF-1α plays an important role in the regulation of proliferation and migration under hypoxia. Autophagy regulates cell proliferation and migration to participate in hypoxia adaptation in plateau animals. Here, the level of autophagy increased significantly in yak coronary arteries with age and was regulated by HIF-1α-mediated hypoxia. In addition, autophagy could also mediate the hypoxic effect on the proliferation and migration of CASMCs. In summary, the results revealed that the increase in yak heart coronary artery thickening with age increases vascular smooth muscle cell proliferation and migration, mainly achieved through hypoxia-mediated HIF-1α-regulated autophagy. These results contribute to understanding how the heart adapts to life in a hypoxic environment.

A 'torn bag mechanism' of small extracellular vesicle release via limiting membrane rupture of en bloc released amphisomes (amphiectosomes)

Recent studies showed an unexpected complexity of extracellular vesicle (EV) biogenesis pathways. We previously found evidence that human colorectal cancer cells in vivo release large multivesicular body-like structures en bloc. Here, we tested whether this large EV type is unique to colorectal cancer cells. We found that all cell types we studied (including different cell lines and cells in their original tissue environment) released multivesicular large EVs (MV-lEVs). We also demonstrated that upon spontaneous rupture of the limiting membrane of the MV-lEVs, their intraluminal vesicles (ILVs) escaped to the extracellular environment by a 'torn bag mechanism'. We proved that the MV-lEVs were released by ectocytosis of amphisomes (hence, we termed them amphiectosomes). Both ILVs of amphiectosomes and small EVs separated from conditioned media were either exclusively CD63 or LC3B positive. According to our model, upon fusion of multivesicular bodies with autophagosomes, fragments of the autophagosomal inner membrane curl up to form LC3B positive ILVs of amphisomes, while CD63 positive small EVs are of multivesicular body origin. Our data suggest a novel common release mechanism for small EVs, distinct from the exocytosis of multivesicular bodies or amphisomes, as well as the small ectosome release pathway.

Knockout of p21-Activated Kinase 4 Stimulates MHC I Expression of Pancreatic Cancer Cells via an Autophagy-Independent Pathway

BACKGROUND/OBJECTIVES

Pancreatic ductal adenocarcinoma (PDA) is one of the most malignant solid cancers. KRAS mutation accounts for over 90% of cases. p21-activated kinases (PAKs) act downstream of KRAS and are involved in tumorigenesis. The inhibition of PAK4 suppresses PDA by stimulating the tumor infiltration of cytotoxic T cells. The major histocompatibility complex class I (MHC I) is a key in presenting antigens to cytotoxic T cells. MHC I degradation via autophagy promotes the immune evasion of pancreatic cancer. We investigated the effect of PAK4 inhibition on MHC I expression and autophagy.

METHODS

In this study, using proteomic analysis, fluorescence-activated cell sorting (FACS), and immunoblotting, we examined the effect of PAK4 knockout (KO) in human PDA cells on the expression of MHC I and autophagy to identify the mechanism involved in the stimulation of cytotoxic T cells by PAK4 inhibition.

RESULTS

We found that PAK4 KO increased MHC I expression in two human PDA cell lines: MiaPaCa-2 and PANC-1. PAK4 KO also increased cancer cell autophagy. However, the inhibition of autophagy by chloroquine (CQ) did not affect the effect of PAK4 KO on apoptosis and cell death. More importantly, the inhibition of autophagy by CQ did not alter the expression of MHC I stimulated by PAK4 KO, indicating that PAK4 KO stimulated MHC I expression via an autophagy-independent pathway.

CONCLUSIONS

We identified a role of PAK4 in MHC I expression by PDA cells, which is independent of autophagy.

Kinase Inhibitor-Induced Cell-Type Specific Vacuole Formation in the Absence of Canonical ATG5-Dependent Autophagy Initiation Pathway

Pyridinyl-imidazole class p38 MAPKα/β (MAPK14/MAPK11) inhibitors including SB202190 have been shown to induce cell-type specific defective autophagy resulting in micron-scale vacuole formation, cell death, and tumor suppression. We had earlier shown that this is an off-target effect of SB202190. Here we provide evidence that this vacuole formation is independent of ATG5-mediated canonical autophagosome initiation. While SB202190 interferes with autophagic flux in many cell lines parallel to vacuolation, autophagy-deficient DU-145 cells and CRISPR/Cas9 gene-edited ATG5-knockout A549 cells also undergo vacuolation upon SB202190 treatment. Late-endosomal GTPase RAB7 colocalizes with these compartments and RAB7 GTP-binding is essential for SB202190-induced vacuolation. A screen for modulators of SB202190-induced vacuolation revealed molecules including multi-kinase inhibitor sorafenib as inhibitors of vacuolation and sorafenib co-treatment enhanced cytotoxicity of SB202190. Moreover, VE-821, an ATR inhibitor was found to phenocopy the cell-type specific vacuolation response of SB202190. To identify the factors determining the cell-type specificity of vacuolation induced by SB-compounds and VE-821, we compared the transcriptomics data from vacuole-forming and non-vacuole-forming cancer cell lines and identified a gene expression signature that may define sensitivity of cells to these small-molecules. Further analyses using small molecule tools and the gene signature discovered here, could reveal novel mechanisms regulating this interesting anti-cancer phenotype.

Decoration of Autophagy Detecting Nanoparticle with an Anionic Fluorochrome Enhances Multispectral Characterization of Autophagosome Location and Flux

Autophagy is a key biological process that has proven extremely difficult to detect noninvasively. To address this, an autophagy detecting nanoparticle (ADN) was recently developed, consisting of an iron oxide nanoparticle decorated with cathepsin-cleavable arginine-rich peptides bound to the near-infrared fluorochrome Cy5.5. Activation of the probe in autophagolysosomes results in the emission of Cy5.5 fluorescence and provides a measure of autophagosome flux. However, in the early autophagosome ADN fluorescence is silent due to fluorochrome stacking. Here, we introduce to ADN a second non-cleavable fluorophore that allows the probe to be tracked through all stages of autophagy. The nature of the secondary/tracking fluorophore has a profound effect on the activation of ADN and the emission of Cy5.5 fluorescence. The lead candidate, ADN2 (featuring AZDye546 as the secondary fluorophore) has the highest activation rate and change in Cy5.5 fluorescence. Absorbance and fluorescence spectrophotometry methods show that the negatively charged AZDye546 interacts with the positively charged polyarginine motifs of the Cy5.5-polyArg activatable fluorophore, resulting in enhanced baseline quenching of the Cy5.5 signal in the nanoprobe. Flow cytometry shows that the activation of ADN2 remains specific for autophagy and is strongly modulated by classical regulators of autophagy (starvation, bafilomycin) and genetic deletion of key autophagy proteins (ATG5, ATG7). ADN2 co-localized strongly with LC3-GFP positive autophagosomes and provided readouts of in vivo probe delivery and activation in the hearts of fed/starved mice. ADN2 enhances the ability to image autophagy without genetic transfection of cells/animals and underscores the possible effects for unanticipated interactions between fluorochromes and other moieties on the surface of decorated nanoparticles.

PTB Regulates Keloid Fibroblast Migration and Proliferation Through Autophagy

BACKGROUND

Keloid disease is a chronic fibroproliferative disease that occurs after tissue injury, and the currently available treatments are unsatisfactory.

OBJECTIVES

We aimed to explore the level of autophagy in keloid fibroblasts (KFbs) and adjacent normal fibroblasts (NFbs). In addition, whether polypyrimidine tract-binding protein (PTB) regulates the biological functions of KFbs via autophagy was also investigated.

METHODS

The morphology of fibroblasts in normal skin and keloids was observed transmission electron microscopy. We silenced PTB with PTB-specific siRNA to determine whether PTB-regulated KFb proliferation. Acridine orange and LysoTracker Red staining was performed to label acidic compartments. Interestingly, when autophagy was inhibited by wortmannin, the PTB knockdown-mediated decrease in KFb migration and proliferation was abolished, while the collagen I and III levels were not altered; these results indicated that PTB regulated the migration and proliferation of KFbs via autophagy, while collagen synthesis occurred independently of PTB regulation.

RESULTS

Many activities related to the survival and function of KFbs are controlled by PTB. Transmission electron microscopy revealed more autophagosomes and autolysosomes in KFbs than in NFbs. PTB induced autophagy in KFbs, as demonstrated by the significantly greater number of autophagosomes in KFbs after PTB knockdown, which was revealed by acridine orange and LysoTracker staining.

CONCLUSIONS

Our study is the first to show that PTB regulates the migration and proliferation of KFbs via autophagy and that PTB regulates collagen synthesis in KFbs in an autophagy-independent manner.

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The TFEB activator clomiphene citrate ameliorates lipid metabolic syndrome pathology by activating lipophagy and lipolysis

The balance between lipid synthesis and lipid catabolism is critical to maintain energy homeostasis. Lipophagy and lipolysis are two important pathways for lipid selective catabolism. Defects in lipophagy and lipolysis are linked to lipid metabolic diseases. Transcription factor EB (TFEB) is a master regulator of autophagy and lysosome biogenesis, as well as lipid metabolism by promoting expression of genes encoding fat catabolic lipases. Therefore, targeting TFEB provides a novel potential strategy for the treatment of lipid metabolic diseases. In this study, we showed that the TFEB activator clomiphene citrate (CC) activated the autophagy-lysosome and lipolysis pathways, and promoted degradation of lipid droplets induced by the free fatty acids oleate and palmitate in HepG2 cells. Moreover, CC treatment promoted lipid catabolism and attenuated obesity, restored lipid levels, blood glucose levels and insulin resistance, hepatocellular injury and hepatic steatosis, as well as liver inflammation in the HFD fed mice. In addition, we found that En-CC, a trans-isomer of CC, displayed less toxicity and more efficient activation of TFEB. Consistent with CC, En-CC treatment improved lipid metabolic syndrome pathology. These findings demonstrate that CC promotes clearance of lipids and ameliorates HFD-induced lipid metabolic syndrome pathology through activating TFEB-mediated lipophagy and lipolysis, indicating that CC has the potential to be used to treat lipid metabolic diseases.

The steroid hormone 20-hydroxyecdysone induces lipophagy via the brain-adipose tissue axis by promoting the adipokinetic hormone pathway

Lipophagy is a way to degrade lipids; however, the molecular mechanisms are not fully understood. Using the holometabolous lepidopteran insect Helicoverpa armigera, cotton bollworm, as a model, we revealed that the larval fat body undergoes lipophagy during metamorphosis, and lipophagy is essential for metamorphosis. The steroid hormone 20-hydroxyecdysone (20E) induced lipophagy by promoting the expression of the peptide hormone adipokinetic hormone (AKH, the insect analog of glucagon) and the adipokinetic hormone receptor (AKHR). Akh was highly expressed in the brain and Akhr was expressed in various tissues. The 20E upregulated the expression of Akh and Akhr by its nuclear receptor EcR during metamorphosis. AKH and AKHR increased glucose levels via gluconeogenesis and promoted lipophagy. The high glucose level induced acetylation of FOXO and nuclear localization to promote the expression of lipases and autophagy genes. Thus, the steroid hormone 20E induced lipophagy via the brain-adipose tissue axis by promoting the AKH pathway, which presented nutrients and energy to pupal and adult development during insect metamorphosis after feeding stops.

The dual function of autophagy in doxorubicin-induced cardiotoxicity: Mechanism and natural products

Doxorubicin (DOX) is an anthracycline antitumor drug discovered in 1969, which can care for leukemia, breast cancer, lymphoma, and sarcoma. However, cardiotoxicity induced by DOX seriously limits its clinical value. The etiopathogenesis and therapeutic strategies are not unified. Autophagy is a critical mechanism in the progression of DOX-induced cardiotoxicity (DIC), autophagy intervention is a potential therapeutic strategy for DIC. Natural product has been considered as a complementary and alternative approach to treat cardiovascular disease. In this review, we summarize the pathology of autophagy in DIC and the natural products for DIC therapy.

The Effect of 7-Day Cold Water Acclimation on Autophagic and Apoptotic Responses in Young Males

While cold acclimation can enhance thermoregulation in humans, the potential to improve cellular cold tolerance remains unknown. Thus, this work aims to evaluate the effect of a 7-day cold-water acclimation on the cytoprotective mechanism of autophagy in young males. Further, this work assesses changes in cellular cold tolerance by employing hypothermic ex vivo (whole blood) cooling prior to and following acclimation. Peripheral blood mononuclear cells are isolated before and after cold exposures on days 1, 4, and 7 of acclimation and following ex vivo cooling. Proteins associated with autophagy, apoptosis, the heat shock response, and inflammation are analyzed via Western blotting. Indicators of autophagic dysfunction paired with increased apoptotic signaling are prevalent at the beginning of acclimation. At the end of acclimation, autophagic activity increased while apoptotic and inflammatory signaling decreased. Although an elevated heat shock response is observed following cold exposure, this does not change throughout the acclimation. Further, improvements of autophagic activity are observed during ex vivo cooling along with a reduction of apoptotic signaling, albeit still elevated compared to basal levels. This work shows that 7-day cold acclimation elicits improvements in cellular cold tolerance in young males through enhanced autophagic responses concomitant with reductions in apoptotic signaling.

Dawn-to-dusk intermittent fasting is associated with overexpression of autophagy genes: A prospective study on overweight and obese cohort

AIM AND BACKGROUND

A growing body of evidence supports the impact of intermittent fasting (IF) on longevity and healthy aging via the modulation of autophagy genes. The activation of the catabolic autophagic machinery (LAMP2, LC3B, ATG5, and ATG4D) has protective effects against degenerative aging and chronic diseases. This research examined the changes in the expression of the aforementioned genes upon the observance of dawn-to-dusk IF among metabolically healthy participants with overweight and obesity.

METHODS

Fifty-one (51) participants (36 males and 15 females, 38.84 ± 11.73 years) with overweight and obesity (BMI = 29.75 ± 5.04 kg/m2) were recruited and monitored before and at the end of the commencement of the four-week IF. Six healthy subjects with normal BMI (21.4 ± 2.20 kg/m2) were recruited only to standardize the reference for normal levels of gene expressions. At the two time points, anthropometric, biochemical, and dietary assessments were performed, and LAMP2, LC3B, ATG5, and ATG4D gene expressions were assessed using qRT-PCR on RNA extracted from whole blood samples.

RESULTS

At the end of IF, and compared to the pre-fasting levels, the relative gene expressions among participants with overweight/obesity were significantly increased for the three autophagy genes LAMP2, LC3B, and ATG5, with increments of about 4.2 folds, 1.9-fold, and 1.4-fold, respectively. In contrast, the increase in the ATG4D gene was not significant. Concomitantly, significant decreases were found in body weight, BMI, fat mass, body fat percent, hip and waist circumferences, LDL, IL-6, and TNF-a (P < 0.05), While HDL, IL-10, and CD163 significantly increased (P < 0.05). Binary logistic regression analysis for genetic expressions showed no significant association between high-energy intake, waist circumference, or obesity and the four gene expressions.

CONCLUSIONS

Four consecutive weeks of dawn-to-dusk IF of Ramadan is associated with the upregulation of autophagy gene expressions in participants with overweight/obesity, and this may explain, at least in part, its favorable short-term temporal metabolic and health-improving effects on early aging-related markers. Hence, IF presumably may entail a protective impact against early markers of aging and metabolic diseases in participants with overweight/obesity.

ATG8ylation of vacuolar membrane protects plants against cell wall damage

Vacuoles are essential for cellular metabolism and growth and the maintenance of internal turgor pressure. They sequester lytic enzymes, ions and secondary metabolites that, if leaked into the cytosol, could lead to cell death. Despite their pivotal roles, quality control pathways that safeguard vacuolar integrity have remained elusive in plants. Here we describe a conserved vacuolar quality control pathway that is activated upon cell wall damage in a turgor-pressure-dependent manner. Cell wall perturbations induce a distinct modification-ATG8ylation-on the vacuolar membrane (tonoplast) that is regulated by the V-ATPase and ATG8 conjugation machinery. Genetic disruption of tonoplast ATG8ylation impairs vacuolar integrity, leading to cell death. Together, our findings reveal a homeostatic pathway that preserves vacuolar integrity upon cell wall damage.

Role of Microglial Mitophagy in Alleviating Postoperative Cognitive Dysfunction: a Mechanistic Study

Postoperative cognitive dysfunction (POCD), a common complication following anesthesia and surgery, is influenced by hippocampal neuroinflammation and microglial activation. Mitophagy, a process regulating inflammatory responses by limiting the accumulation of damaged mitochondria, plays a significant role. This study aimed to determine whether regulating microglial mitophagy and the cGAS-STING pathway could alleviate cognitive decline after surgery. Exploratory laparotomy was performed to establish a POCD model using mice. Western blotting, immunofluorescence staining, transmission electron microscopy, and mt-Keima assays were used to examine microglial mitophagy and the cGAS-STING pathway. Quantitative polymerase chain reaction (qPCR) was used to detect inflammatory mediators and cytosolic mitochondrial DNA (mtDNA) levels in BV2 cells. Exploratory laparotomy triggered mitophagy and enhanced the cGAS-STING pathway in mice hippocampi. Pharmacological treatment reduced microglial activation, neuroinflammation, and cognitive impairment after surgery. Mitophagy suppressed the cGAS-STING pathway in mice hippocampi. In vitro, microglia-induced inflammation was mediated by mitophagy and the cGAS-STING pathway. Small interfering RNA (siRNA) of PINK1 hindered mitophagy activation and facilitated the cytosolic release of mtDNA, resulting in the initiation of the cGAS-STING pathway and innate immune response. Microglial mitophagy inhibited inflammatory responses via the mtDNA-cGAS-STING pathway inducing microglial mitophagy and inhibiting the mtDNA-cGAS-STING pathway may be an effective therapeutic approach for patients with POCD.

Arginase Activity Inhibition With Thymoquinone Induces a Hybrid Type of Cell-Death in MDA-MB-231 Cell Line

Arginase plays a crucial role in the urea cycle; it also has immunosuppressive and pro-tumor effects. The present study aimed to assess the effects of arginase inhibition by thymoquinone (2-Isopropyl-5-methyl-1,4-benzoquinone), an active compound of Nigella sativa, on cell death in the MDA-MB-231 triple-negative breast tumor cell line. Cell viability assays, Western blot analysis, and flow cytometry analysis were used to characterize oxidative stress and cell death. Our results showed that inhibition of arginase activity with thymoquinone significantly increased intracellular nitric oxide levels and resulted in overproduction of cellular and mitochondrial reactive oxygen species. Reductions in cell viability, cycle arrest, and increased cell death were also observed. Loss of transmembrane mitochondrial potential, activation of caspase-3, -7, and -9, cleavage of PARP, condensation and/or fragmentation of the nuclei, suggest that this cell death involved apoptosis. Furthermore, a cytoplasm vacuole formation and an increase in the ratio of [LC3-II/LC3-I] suggests a concomitant activation of autophagy with apoptosis. Altogether, the present study highlighted that arginase inhibition with thymoquinone induces a hybrid type of cell death defined as oxiapoptophagy. Thus, arginase inhibition with thymoquinone in the MDA-MB-231 cell line could be, in part, involved in the anticancer effect of thymoquinone.

MDPAO1 peptide from human milk enhances brown adipose tissue thermogenesis and mitigates obesity

The regulatory effect of breastfeeding on offspring metabolism has garnered significant attention as an effective strategy in combating childhood obesity. However, the underlying mechanism remains largely unknown. Through integrated analysis of multiple human milk peptide databases and functional screening, MDPAO1 (milk-derived peptide associated with obesity 1) was identified as having potential activity in promoting the expression of thermogenic genes. In lactating mice, intervention with MDPAO1 enhanced the thermogenic phenotype of brown adipose tissue (BAT) and overall metabolic activity. Moreover, MDPAO1 intervention led to reduced body weight gain, increased brown fat mass, and improved glucose tolerance and insulin sensitivity in a mouse model of high-fat diet (HFD)-induced obesity. RNA-seq analysis of BAT post-MDPAO1 intervention revealed close association with mitochondrial oxidative respiratory chain and mitophagy. Subsequent in vitro experiments conducted on primary brown adipocytes confirmed that MDPAO1 inhibited mitophagy, increased mitochondrial mass, and elevated levels of mitochondrial respiratory chain complexes. In conclusion, this study underscores the potential of MDPAO1, a peptide enriched in breast milk, in activating the thermogenic phenotype of brown adipose tissue and mitigating obesity, thus offering novel insights into the mechanisms underlying breastfeeding's role in preventing childhood obesity.

Nuclear stiffness through lamin A/C overexpression differentially modulates chromosomal instability biomarkers

BACKGROUND INFORMATION

Mitosis is crucial for the faithful transmission of genetic material, and disruptions can result in chromosomal instability (CIN), a hallmark of cancer. CIN is a known driver of tumor heterogeneity and anti-cancer drug resistance, thus highlighting the need to assess CIN levels in cancer cells to design effective targeted therapy. While micronuclei are widely recognized as CIN markers, we have recently identified the toroidal nucleus, a novel ring-shaped nuclear phenotype arising as well from chromosome mis-segregation.

RESULTS

Here, we examined whether increasing nuclear envelope stiffness through lamin A/C overexpression could affect the formation of toroidal nuclei and micronuclei. Interestingly, lamin A/C overexpression led to an increase in toroidal nuclei while reducing micronuclei prevalence. We demonstrated that chromatin compaction and nuclear stiffness drive the formation of toroidal nuclei. Furthermore, inhibition of autophagy and lysosomal function elevated the frequency of toroidal nuclei without affecting the number of micronuclei in the whole cell population. We demonstrated that this divergence between the two CIN biomarkers is independent of defects in lamin A processing.

CONCLUSIONS AND SIGNIFICANCE

These findings uncover a complex interplay between nuclear architecture and levels of CIN, advancing our understanding of the mechanisms supporting genomic stability and further contributing to cancer biology.

Periodontopathogen-Related Cell Autophagy-A Double-Edged Sword

The periodontium is a highly organized ecosystem, and the imbalance between oral microorganisms and host defense leads to periodontal diseases. The periodontal pathogens, mainly Gram-negative anaerobic bacteria, colonize the periodontal niches or enter the blood circulation, resulting in periodontal tissue destruction and distal organ damage. This phenomenon links periodontitis with various systemic conditions, including cardiovascular diseases, malignant tumors, steatohepatitis, and Alzheimer's disease. Autophagy is an evolutionarily conserved cellular self-degradation process essential for eliminating internalized pathogens. Nowadays, increasing studies have been carried out in cells derived from periodontal tissues, immune system, and distant organs to investigate the relationship between periodontal pathogen infection and autophagy-related activities. On one hand, as a vital part of innate and adaptive immunity, autophagy actively participates in host resistance to periodontal bacterial infection. On the other, certain periodontal pathogens exploit autophagic vesicles or pathways to evade immune surveillance, therefore achieving survival within host cells. This review provides an overview of the autophagy process and focuses on periodontopathogen-related autophagy and their involvements in cells of different tissue origins, so as to comprehensively understand the role of autophagy in the occurrence and development of periodontal diseases and various periodontitis-associated systemic illnesses.

Cysteinyl leukotriene receptor 1 modulates retinal immune cells, vascularity and proteolytic activity in aged mice

Cysteinyl leukotrienes (CysLTs) modulate the immune response, the microvasculature, cell stress and the endosomal-lysosomal system, and are involved in cellular aging. Interestingly, CysLT receptor 1 (Cysltr1) is highly expressed in the retina, a tissue that is strongly affected by the aging process. Thus, we performed an introductory examination to determine a potential importance of Cysltr1 for cells in the neurovascular unit using qPCR and immunofluorescence analysis, and on proteolytic activity in the retinas of aged mice. Aged mice (~84 weeks) were treated orally with vehicle or 10 mg/kg montelukast (MTK), a specific Cysltr1 inhibitor, for 8 weeks, 5x/week. The retinas of young mice (~11 weeks) served as controls. Compared with young control mice, aged mice exhibited increased numbers of microglia and a reduced retinal capillary diameter, but these age-dependent changes were abrogated by MTK treatment. Retinal protein levels of the ubiquitin binding protein sequestosome-1 were amplified by aging, but were reduced by MTK treatment. Interestingly, retinal proteasome activity was decreased in aged mice, whereas Cysltr1 inhibition increased this activity. The reduction in immune cells caused by Cysltr1 suppression may dampen neuroinflammation, a known promoter of tissue aging. Additionally, an increase in capillary diameter after Cysltr1 inhibition could have a beneficial effect on blood flow in aged individuals. Furthermore, the increase in proteolytic activity upon Cysltr1 inhibition could prevent the accumulation of toxic deposits, which is a hallmark of aged tissue. Overall, Cysltr1 is a promising target for modulating the impact of aging on retinal tissue.

VPS18 contributes to phagosome membrane integrity in Mycobacterium tuberculosis-infected macrophages

Mycobacterium tuberculosis (Mtb) has evolved to be exquisitely adapted to survive within host macrophages. The capacity to damage the phagosomal membrane has emerged as central to Mtb virulence. While Mtb factors driving membrane damage have been described, host factors that maintain phagosomal integrity or repair Mtb-induced damage to contain the pathogen remain largely unknown. We used a genome-wide CRISPR screen to identify host factors required to repair Mtb-damaged phagosomal membranes. Vacuolar protein sorting-associated protein 18 (VPS18), a member of the HOPS and CORVET trafficking complexes, was among the top hits. VPS18 colocalized with Mtb in macrophages beginning shortly after infection, and VPS18-knockout macrophages demonstrated increased damage of Mtb-containing phagosomes without impaired autophagy. Mtb grew more robustly in VPS18-knockout cells, and the first-line antituberculosis antibiotic pyrazinamide was less effective. Our results identify VPS18 as required for phagosomal membrane integrity in Mtb-infected cells and suggest that modulating phagosome integrity may hold promise for improving the efficacy of antibiotic treatment for TB.

Recycle, repair, recover: the role of autophagy in modulating skeletal muscle repair and post-exercise recovery

Skeletal muscle is a highly plastic tissue that can adapt relatively rapidly to a range of stimuli. In response to novel mechanical loading, e.g. unaccustomed resistance exercise, myofibers are disrupted and undergo a period of ultrastructural remodeling to regain full physiological function, normally within 7 days. The mechanisms that underpin this remodeling are believed to be a combination of cellular processes including ubiquitin-proteasome/calpain-mediated degradation, immune cell infiltration, and satellite cell proliferation/differentiation. A relatively understudied system that has the potential to be a significant contributing mechanism to repair and recovery is the autophagolysosomal system, an intracellular process that degrades damaged and redundant cellular components to provide constituent metabolites for the resynthesis of new organelles and cellular structures. This review summarizes our current understanding of the autophagolysosomal system in the context of skeletal muscle repair and recovery. In addition, we also provide hypothetical models of how this system may interact with other processes involved in skeletal muscle remodeling and provide avenues for future research to improve our understanding of autophagy in human skeletal muscle.

Genetically-encoded targeted protein degradation technology to remove endogenous condensation-prone proteins and improve crop performance

Effective modulation of gene expression in plants is achievable through tools like CRISPR and RNA interference, yet methods for directly modifying endogenous proteins remain lacking. Here, we identify the E3 ubiquitin ligase E3TCD1 and develope a Targeted Condensation-prone-protein Degradation (TCD) strategy. The X-E3TCD1 fusion protein acts as a genetically engineered degrader, selectively targeting endogenous proteins prone to condensation. For example, a transgenic E3TCD1 fusion with Teosinte branched 1 (TB1) degrades the native TB1 protein, resulting in increased tiller numbers in rice. Additionally, conditional degradation of the negative defense regulator Early Flowering 3 via a pathogen-responsive ProTBF1-uORFsTBF1 cassette enhances rice blast resistance without affecting flowering time in the absence of pathogen. Unlike prevailing targeted protein degradation strategies, the TCD system does not rely on small molecules, antibodies, or genetic knock-in fusion tags, demonstrating its promise as a transgene-based approach for optimizing crop performance.

The di-leucine motif in the host defense peptide LL-37 is essential for initiation of autophagy in human macrophages

The human cathelicidin peptide LL-37 induces autophagy in human macrophages. Different post-translational modifications (PTMs) such as citrullination, acetylation, and formylation impact LL-37, yet their effect on autophagy remains unknown. Thus, we set out to study how the cellular source could impact PTM of LL-37 and subsequent effects on autophagy initiation. Neutrophil-released LL-37 failed to induce autophagy, unlike macrophage-released LL-37. Mass spectrometry analysis revealed modifications on neutrophil-derived LL-37, especially at the N terminus, while macrophage-derived LL-37 remained mostly native. Native LL-37 initiated autophagy, while formylated and acetylated versions did not. Truncated peptides lacking the N-terminal di-leucine motif or substituted with di-alanine did not initiate autophagy. Native LL-37 failed to initiate autophagy in macrophages with genetic inactivation of dipeptidyl peptidase-1. An intact N-terminal di-leucine motif in LL-37 was crucial for autophagy initiation, and modifications abrogated the effects. This pathway presents a novel way to regulate the effects of LL-37 in infection or inflammation.

Knockdown ATG5 gene by rAAV9 alleviates doxorubicin-induced cardiac toxicity by inhibiting GATA4 autophagic degradation

Doxorubicin (DOX) is a prevalent chemotherapeutic drug for treating several malignancies. However, the mechanisms of DOX induced cardiac toxicity is not fully understood. Previous studies have demonstrated that autophagy activation is essential in DOX-induced cardiac toxicity. Nevertheless, studies on the role of autophagy protein 5 (ATG5) in DOX-induced cardiac toxicity remain limited. Therefore, this study aimed to investigate the role of ATG5 in DOX-induced cardiac toxicity. Mice were intravenously administered DOX (5 mg/kg) for 4 weeks to establish a cardiac toxicity model. Heart function was determined using echocardiography, and cardiac tissue was assessed for protein expression, mRNA levels, fibrosis, and immunofluorescent staining. DOX treatment upregulated autophagy-related gene expression but inhibited autophagic flux in vitro and in vivo. DOX-treated mice exhibited decreased heart function and cardiomyocyte size and increased cardiac fibrosis, oxidative stress, and apoptosis. These effects of DOX were partially alleviated by rAAV9 expressing shRNA-ATG5 and deteriorated by rAAV9-ATG5. We demonstrated that genetic ATG5 knockdown or autophagy inhibition by chemical inhibitors increased GATA4 protein expression, which was reduced by ATG5 overexpression or autophagy activator in vitro and in vivo, suggesting that ATG5-mediated autophagy promoted GATA4 degradation. Moreover, enforced GATA4 re-expression significantly counteracted the toxic effects of ATG5 on DOX-treated hearts. In conclusion, our study demonstrated that manipulating ATG5 expression to regulate GATA4 degradation in the heart may be a promising approach for DOX-induced cardiac toxicity.

MicroRNA mediates the effects of food factors

Food factors elicit physiological effects by interfering with the central dogma system, including DNA methylation, replication, transcription, and translation. MicroRNAs (miRNAs) are noncoding short RNAs that are ∼20 nucleotides long and play a crucial role in the regulation of mRNA levels and translation processes. Importantly, miRNAs can be delivered to different locations in nanovesicles. However, little is known about their roles as mediators of the effects of food factors. This review introduces recent findings on the role of miRNAs in the beneficial effects of food factors, including green tea polyphenols and soybean isoflavones, and discusses the importance of miRNAs as mediators of the beneficial effects of food.

Lysosomes finely control macrophage inflammatory function via regulating the release of lysosomal Fe2+ through TRPML1 channel

Lysosomes are best known for their roles in inflammatory responses by engaging in autophagy to remove inflammasomes. Here, we describe an unrecognized role for the lysosome, showing that it finely controls macrophage inflammatory function by manipulating the lysosomal Fe2+-prolyl hydroxylase domain enzymes (PHDs)-NF-κB-interleukin 1 beta (IL1B) transcription pathway that directly links lysosomes with inflammatory responses. TRPML1, a lysosomal cationic channel, is activated secondarily to ROS elevation upon inflammatory stimuli, which in turn suppresses IL1B transcription, thus limiting the excessive production of IL-1β in macrophages. Mechanistically, the suppression of IL1B transcription caused by TRPML1 activation results from its modulation on the release of lysosomal Fe2+, which subsequently activates PHDs. The activated PHDs then represses transcriptional activity of NF-κB, ultimately resulting in suppressed IL1B transcription. More importantly, in vivo stimulation of TRPML1 ameliorates multiple clinical signs of Dextran sulfate sodium-induced colitis in mice, suggesting TRPML1 has potential in treating inflammatory bowel disease.

Camellia saponin modulates oleic acid/linoleic acid-induced lipogenesis in human sebocytes through lipophagy activation

BACKGROUND

Oily skin not only threatens people with aesthetic and hygienic discomfort but also confronts them with annoying skin problems. To explore new skin care ingredients from herbal or plant extracts and understand their underlying mechanism for sebum control would assist in the discovery of desirable sebosuppressive agents, though it is still a deserving and challenging task.

AIM

To explore the effect of Camellia saponin (CS) on modulating the lipogenesis of human sebocytes. Moreover, to explore the underlying mechanism of CS on oleic acid/linoleic acid (OL) mixture stimulated lipid accumulation.

METHODS

The lipid accumulation model of cells was constructed by OL-induction in vitro. The lipid synthesis in SZ95 sebocytes was detected by Oil Red O, Nile Red and BODIPY staining and the distribution of lipid droplets and autophagosomes were evaluated by transmission electron microscopy (TEM). Fluorescence staining, immunofluorescence and western blot (WB) were used to characterize the spatial localization of lipid droplets (LDs)/autophagosome/lysosome, the levels of LC3 and P62 proteins related to intracellular autophagy, as well as the pH of lysosome.

RESULTS

CS treatment significantly relieved OL-induced lipid accumulation in SZ95 sebocytes. Furthermore, CS maintained lysosomal acid environment to promote the fusion of autophagosome and lysosome, thus recovering the OL-induced blockage of autophagy flow. We also found that CS activated AMPK, and down-regulated mTOR in SZ95 sebocytes.

CONCLUSION

CS was able to relieve OL-stimulated sebum accumulation in cultured human SZ95 sebocytes through lipophagy, in which process CS maintained lysosomal acid environment and activated the AMPK/mTOR pathway.

Dual targeting PD-L1 and 4-1BB to overcome dendritic cell-mediated lenalidomide resistance in follicular lymphoma

Immunomodulatory agent lenalidomide is effective in treating follicular lymphoma (FL). We conducted the first trial of immunotherapy rituximab plus lenalidomide in newly diagnosed FL in China (NCT03715309). One-hundred and fifteen patients were enrolled and treated with rituximab 375 mg/m2 intravenously on day 0 and lenalidomide 25 mg orally on day 1-10 for 6 cycles of induction treatment, as well as lenalidomide for 6 cycles and rituximab for 8 cycles of maintenance treatment. We found that inferior progression-free survival of the patients was significantly associated with elevated serum β2m and lymph node >6 cm, linking to decreased lymphoma cell autophagy and dendritic cell infiltration within the tumor microenvironment. PU.1 transcriptionally downregulated PD-L1 (Programmed death ligand 1) expression and upregulated 4-1BBL (4-1BB ligand) expression, increased lymphoma cell autophagy and dendritic cell maturation via PD-1/PD-L1 and 4-1BB/4-1BBL interaction. In vitro in co-culture system and in vivo in murine xenograft model, knockdown of PU.1 induced lenalidomide resistance, but sensitized FL cells to bi-specific PD-L1/4-1BB antibody or combined treatment of PD-L1 inhibitor and 4-1BB agonist. Collectively, PU.1 is essential in immunomodulatory effect of FL through PD-1/PD-L1- and 4-1BB/4-1BBL-mediated microenvironmental modulation. Dual targeting PD-L1 and 4-1BB could be an alternative immunotherapeutic strategy in the chemo-free era of FL treatment.

Inhibiting Autophagy by Chemicals During SCAPs Osteodifferentiation Elicits Disorganized Mineralization, While the Knock-Out of Atg5/7 Genes Leads to Cell Adaptation

SCAPs (Stem Cells from Apical Papilla), derived from the apex of forming wisdom teeth, extracted from teenagers for orthodontic reasons, belong to the MSCs (Mesenchymal Stromal Cells) family. They have multipotent differentiation capabilities and are a potentially powerful model for investigating strategies of clinical cell therapies. Since autophagy-a regulated self-eating process-was proposed to be essential in osteogenesis, we investigated its involvement in the SCAP model. By using a combination of chemical and genetic approaches to inhibit autophagy, we studied early and late events of osteoblastic differentiation. We showed that blocking the formation of autophagosomes with verteporfin did not induce a dramatic alteration in early osteoblastic differentiation monitored by ALP (alkaline phosphatase) activity. However, blocking the autophagy flux with bafilomycin A1 led to ALP repression. Strikingly, the mineralization process was observed with both compounds, with calcium phosphate (CaP) nodules that remained inside cells under bafilomycin A1 treatment and numerous but smaller CaP nodules after verteporfin treatment. In contrast, deletion of Atg5 or Atg7, two genes involved in the formation of autophagosomes and essential to trigger canonical autophagy, indicated that both genes could be involved differently in the mineralization process with a modification of the ALP activity while final mineralization was not altered.

Microlipophagy from Simple to Complex Eukaryotes

Lipophagy is a selective degradation of lipid droplets in lysosomes or vacuoles. Apart from its role in generating energy and free fatty acids for membrane repair, growth, and the formation of new membranes, lipophagy emerges as a key player in other cellular processes and disease pathogenesis. While fungal, plant, and algal cells use microlipophagy, the most prominent form of lipophagy in animal cells is macrolipophagy. However, recent studies showed that animal cells can also use microlipophagy to metabolize their lipid droplets. Therefore, to no surprise, microlipophagy is conserved from simple unicellular to the most complex multicellular eukaryotes, and many eukaryotic cells can operate both forms of lipophagy. Macrolipophagy is the most studied and better understood at the molecular level, while our understanding of microlipophagy is very sparse. This review will discuss microlipophagy from the perspective of its conservation in eukaryotes and its importance in diseases. To better appreciate the conserved nature of microlipophagy, different organisms and types of cells in which microlipophagy has been reported are also shown in a tabular form. We also point toward the gaps in our understanding of microlipophagy, including the signaling behind microlipophagy, especially in the cells of complex multicellular organisms.

Beclin 1-Mediated Autophagy Is Potentiated by an Interaction with the Neuronal Adaptor FE65

Autophagy is a vital cellular pathway in eukaryotic cells, including neurons, where it plays significant roles in neurodevelopment and maintenance. A crucial step in autophagy is the formation of the class III phosphatidylinositol 3-kinase complex 1 (PI3KC3-C1), which is essential for initiating autophagosome biogenesis. Beclin 1 is the key component of PI3KC3-C1, and its interactors have been reported to affect autophagy. The brain-enriched adaptor protein FE65 has been shown to interact with Alzheimer's disease amyloid precursor protein (APP) to alter the processing of APP. Additionally, FE65 has been implicated in various cellular pathways, including autophagy. We demonstrate here that FE65 positively regulates autophagy. FE65, through its C-terminus, has been shown to interact with Beclin 1. Notably, the overexpression of FE65 enhances Beclin 1-mediated autophagy, whereas this process is attenuated in FE65 knockout cells. Moreover, the stimulatory effect of FE65 on Beclin 1-mediated autophagy is diminished by an FE65 C-terminus deletion mutant that disrupts the FE65-Beclin 1 interaction. Lastly, we have found that the FE65-Beclin 1 interaction modulates the kinase activity of the PI3KC3-C1 complex. Together, we have identified FE65 as a novel Beclin 1 interactor, and this interaction potentiates autophagy.

The anti-senescence effect of D-β-hydroxybutyrate in Hutchinson-Gilford progeria syndrome involves progerin clearance by the activation of the AMPK-mTOR-autophagy pathway

D-β-hydroxybutyrate, BHB, has been previously proposed as an anti-senescent agent in vitro and in vivo in several tissues including vascular smooth muscle. Moreover, BHB derivatives as ketone esters alleviate heart failure. Here, we provide evidence of the potential therapeutic effect of BHB on Hutchinson-Gilford progeria syndrome (HGPS), a rare condition characterized by premature aging and heart failure, caused by the presence of progerin, the aberrant protein derived from LMNA/C gene c.1824C > T mutation. We have assessed several hallmarks of HGPS-senescent phenotype in vitro, such as progerin levels, nuclear morphometric aberrations, nucleolar expansion, cellular senescent morphology, SA-βGal-positive cells, H3K9me3 heterochromatin, γH2AX foci, Lamin B1, p21Waf1/Cip1 and p16CDKN2A abundance, and autophagy. Strikingly, BHB improved nuclear and nucleolar morphometrics, diminished the senescence-phenotype, and unstuck autophagy in HGPS as observed by an enhanced degradation of the cargo protein receptor SQSTM1/p62, suggesting the stimulation of the autophagic flux. Additionally, we observed a decrease in progerin abundance, the cause of senescence in HGPS. Furthermore, compound C, an inhibitor of AMPK, and SBI-0206965, an inhibitor of ULK1/2 and AMPK, which prevent autophagy activation, reversed BHB-induced progerin decline as well as its anti-senescent effect in an AMPK-mTORC1 dependent manner. Altogether, these results suggest that the anti-senescence effect of BHB involves progerin clearance by autophagy activation supporting the potential of BHB for HGPS therapeutics and further preclinical trials.

Hypoxia-triggered ERRα acetylation enhanced its oncogenic role and promoted progression of renal cell carcinoma by coordinating autophagosome-lysosome fusion

Estrogen-related receptor α (ERRα) is dysregulated in many types of cancer and exhibits oncogenic activity by promoting tumorigenesis and metastasis of cancer cells. However, its defined role in renal cell carcinoma (RCC) has not been fully elucidated. To reveal the biological function of ERRα and determine the underlying regulatory mechanism in RCC, the quantitative proteomics analysis and mechanism investigation were conducted. The results demonstrated that ERRα promoted the proliferation and tumorigenesis of RCC cells by maintaining lysosome-dependent autophagy flux. ERRα inhibition impaired the transcriptional expression of LAMP2 and VAMP8 and blocked the fusion of autophagosomes with lysosomes, causing the impairment of the autophagy-lysosome pathway and tumor repression in RCC. Moreover, VHL mutant-induced hyperactive hypoxia signaling in RCC triggered p300/CBP-mediated acetylation at the DNA-binding domain of ERRα, and this acetylation promoted its affinity toward targeting DNA and Parkin-mediated ubiquitination and proteasome-dependent degradation. This regulatory model enhanced ERRα transactivation on the expression of LAMP2 and VAMP8, which then maintained autophagy flux and RCC progression. Pharmaceutical inhibition on ERRα acetylation-mediated autophagy-lysosome pathway led to growth repression and sunitinib sensitivity of RCC cells. Taken together, this study uncovered a novel regulatory mechanism of acetylation contributing to the transcriptional performance and the oncogenic role of ERRα in RCC progression by modulating the autophagy-lysosome pathway. These findings might provide a novel approach for the clinical diagnosis and resolution of sunitinib resistance of RCC.

Diabetes mellitus and glymphatic dysfunction: Roles for oxidative stress, mitochondria, circadian rhythm, artificial intelligence, and imaging

Diabetes mellitus (DM) is a debilitating disorder that impacts all systems of the body and has been increasing in prevalence throughout the globe. DM represents a significant clinical challenge to care for individuals and prevent the onset of chronic disability and ultimately death. Underlying cellular mechanisms for the onset and development of DM are multi-factorial in origin and involve pathways associated with the production of reactive oxygen species and the generation of oxidative stress as well as the dysfunction of mitochondrial cellular organelles, programmed cell death, and circadian rhythm impairments. These pathways can ultimately involve failure in the glymphatic pathway of the brain that is linked to circadian rhythms disorders during the loss of metabolic homeostasis. New studies incorporate a number of promising techniques to examine patients with metabolic disorders that can include machine learning and artificial intelligence pathways to potentially predict the onset of metabolic dysfunction.

Enhancing metformin efficacy with cholecalciferol and taurine in diabetes therapy: Potential and limitations

Diabetes mellitus, particularly type 2 diabetes mellitus (T2DM), poses a significant global health challenge. Traditional management strategies primarily focus on glycemic control; however, there is a growing need for comprehensive approaches addressing the complex pathophysiology of diabetes complications. The recent study by Attia et al explores the potential of a novel therapy combining metformin with cholecalciferol (vitamin D3) and taurine to mitigate T2DM-related complications in a rat model. The findings indicate that this treatment combination improves glycemic control and reduces oxidative stress, inflammation, and lipid abnormalities. However, the study is limited by a lack of safety profile data and in-depth molecular mechanism insights. This editorial critically highlights the study's strengths and weaknesses, compares it against other combination therapy research in T2DM, and underscores the need to explore further the mechanisms underpinning the observed therapeutic effects and investigate the safety profile of this novel approach.

Gallbladder carcinoma in the era of artificial intelligence: Early diagnosis for better treatment

Gallbladder carcinoma (GBC) is the most common malignant tumor of biliary tract, with poor prognosis due to its aggressive nature and limited therapeutic options. Early detection of GBC is a major challenge, with most GBCs being detected accidentally during cholecystectomy procedures for gallbladder stones. This letter comments on the recent article by Deqing et al in the World Journal of Gastrointestinal Oncology, which summarized the various current methods used in early diagnosis of GBC, including endoscopic ultrasound (EUS) examination of the gallbladder for high-risk GBC patients, and the use of EUS-guided elastography, contrast-enhanced EUS, trans-papillary biopsy, natural orifice transluminal endoscopic surgery, magnifying endoscopy, choledochoscopy, and confocal laser endomicroscopy when necessary for early diagnosis of GBC. However, there is a need for novel methods for early GBC diagnosis, such as the use of artificial intelligence and non-coding RNA biomarkers for improved screening protocols. Additionally, the use of in vitro and animal models may provide critical insights for advancing early detection and treatment strategies of this aggressive tumor.

Xiaoai Jiedu recipe reduces cell survival and induces apoptosis in hepatocellular carcinoma by stimulating autophagy via the AKT/mTOR pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The Xiaoai Jiedu recipe (XJR) is a traditional Chinese medicine formulation used in clinical settings to treat liver cancer. It has shown promising effectiveness by combining herbal and animal-derived ingredients, offering a new approach to cancer treatment. However, its mechanism of action is poorly understood.

AIM OF THE STUDY

The molecular processes underlying the inhibitory effects of the XJR on hepatocellular cancer (HCC) were investigated.

MATERIALS AND METHODS

The primary chemical components of XJR and associated disease targets relevant to HCC were anticipated and compiled using a database. The potential targets and processes by which XJR influenced HCC were investigated using GO and KEGG enrichment analyses, as well as protein-protein interaction (PPI) networks. Transmission electron microscopy, laser confocal microscopy, and Western blotting were used to evaluate autophagy, while CCK-8 assays measured cell viability and Western blotting and flow cytometry evaluated apoptosis. In vivo assays were conducted employing an HCC xenograft mouse model.

RESULTS

Network pharmacology analysis identified 456 intersecting targets between XJR and HCC. The top five active components are quercetin, cholesterol, jaceosidine, eupafolin, and oleanolic acid. The key targets include TP53, AKT1, IL6, EGFR, SRC, HSP90AA1, TNF, IL1B, MYC, and CASP3. Additionally, the autophagy pathway was found to be one of the main pathways through which XJR intervenes in HCC. The increased quantity of autophagosomes and autolysosomes, the overexpression of Beclin1 and LC3A/B-II proteins, and the downregulation of P62 all suggest that XJR stimulated autophagy in HCC cells. Functional tests employing pathway-specific activators and inhibitors and siRNA-based knockdown demonstrated that XJR promoted autophagy by blocking AKT/mTOR signaling. Furthermore, XJR reduced the viability of HCC cells and promoted apoptosis by upregulating apoptosis proteins. Autophagy inhibitors and Beclin1 silencing reversed these effects. Research conducted in vivo showed that XJR activated autophagy through the AKT/mTOR axis, thereby markedly reducing tumor growth and inducing tumor cell demise.

CONCLUSIONS

These studies show that XJR activates autophagy in both cellular and animal models to induce apoptosis and decrease HCC cell proliferation, as shown by network pharmacology and verification assays. Further, these findings provide experimental evidence that the anti-tumor activity of XJR involves autophagy stimulation.