PINK1/Park2-Mediated Mitophagy Relieve Non-Alcoholic Fatty Liver Disease.

Up to now, there's a limited number of studies on the relationship between PINK1/Park2 pathway and mitophagy in NAFLD. To investigate the effect of Park2-mediated mitophagy on non-alcoholic fatty liver disease (NAFLD). Oleic acid was used for the establishment of NAFLD model. Oil red-dyed lipid drops and mitochondrial alternations were observed by transmission electron microscopy. Enzymatic kit was used to test lipid content. The levels of IL-8 and TNF-alpha were determined by ELISA. Lenti-Park2 and Park2-siRNA were designed to upregulate and downregulate Park2 expression, respectively. The changing expression of PINK and Park2 was detected by RT-qPCR and Western blot. Immunofluorescence staining was applied to measure the amount of LC3. Successful NAFLD modeling was featured by enhanced lipid accumulation, as well as the elevated total cholesterol (TC), triglyceride (TG), TNF-alpha and IL-8 levels. Mitochondria in NAFLD model were morphologically and functionally damaged. Park2 expression was upregulated by lenti-Park2 and downregulated through Park2-siRNA. The PINK1 expression showed the same trend as Park2 expression. Immunofluorescence staining demonstrated that the when Park2 was overexpressed, more LC3 protein on mitochondrial autophagosome membrane was detected, whereas Park2 knockdown impeded LC3' locating on the membrane. The transmission electron microscopy image exhibited that the extent of damage to the mitochondrial in NAFLD model was revered by enhanced Park2 expression but further exacerbated by reduced Park2 expression. Park2-mediated mitophagy could relive NAFLD and may be a novel therapeutic target for NAFLD treatment. Keywords: Non-alcoholic Fatty Liver Disease (NAFLD), Mitophagy, PINK1/Park2, Park2, PINK1.

Multi-omics analysis revealed that the protein kinase MoKin1 affected the cellular response to endoplasmic reticulum stress in the rice blast fungus, Magnaporthe oryzae.

BACKGROUND: Previous studies have shown that protein kinase MoKin1 played an important role in the growth, conidiation, germination and pathogenicity in rice blast fungus, Magnaporthe oryzae. ΔMokin1 mutant showed significant phenotypic defects and significantly reduced pathogenicity. However, the internal mechanism of how MoKin1 affected the development of physiology and biochemistry remained unclear in M. oryzae. RESULT: This study adopted a multi-omics approach to comprehensively analyze MoKin1 function, and the results showed that MoKin1 affected the cellular response to endoplasmic reticulum stress (ER stress). Proteomic analysis revealed that the downregulated proteins in ΔMokin1 mutant were enriched mainly in the response to ER stress triggered by the unfolded protein. Loss of MoKin1 prevented the ER stress signal from reaching the nucleus. Therefore, the phosphorylation of various proteins regulating the transcription of ER stress-related genes and mRNA translation was significantly downregulated. The insensitivity to ER stress led to metabolic disorders, resulting in a significant shortage of carbohydrates and a low energy supply, which also resulted in severe phenotypic defects in ΔMokin1 mutant. Analysis of MoKin1-interacting proteins indicated that MoKin1 really took participate in the response to ER stress. CONCLUSION: Our results showed the important role of protein kinase MoKin1 in regulating cellular response to ER stress, providing a new research direction to reveal the mechanism of MoKin1 affecting pathogenic formation, and to provide theoretical support for the new biological target sites searching and bio-pesticides developing.

Hyperbaric Lidocaine Aggravates Diabetic Neuropathic Pain by Targeting p38 MAPK/ERK and PINK1/Parkin-Mediated Mitophagy Signaling Pathway.

BACKGROUND: Diabetic neuropathic pain (DNP) is a complication of diabetes mellitus (DM). Hyperbaric lidocaine (HL), a local anesthetics drug, has neurotoxicity. The present study aims to study the effect and molecular mechanisms of HL on spinal nerve injury in DNP. METHODS: The DNP rat model was established through a high-fat-glucose diet in combination with Streptozotocin (STZ) administration. SB203580 and PD98059 were utilized to inhibit p38 mitogen-activated protein kinase (p38 MAPK) and extracellular signal-regulated kinase (ERK). The mechanical paw withdrawal threshold (PWT) and the thermal paw withdrawal latency (PWL) were tested to evaluate rats' mechanical allodynia and thermal hyperalgesia. Hematoxylin-eosin (H&E) and terminal deoxynucleotidyltransferase-mediated dUTP nick-end Labeling (TUNEL) staining were performed to evaluate the pathological changes and neuron apoptosis in spinal cord tissues of L4-5. Western blotting analysis and reverse transcription-polymerase chain reaction (RT-qPCR) assay were used to measure the levels of proteins and mRNAs, respectively. RESULTS: PWT and PWL were decreased in DNP rats with serious spinal nerve injury. HL administration downregulated the PWT and PWL and aggravated spinal nerve injury in DNP rats, but isobaric lidocaine had no effects on these changes. Meanwhile, p38 MAPK/ERK signaling and PTEN-induced kinase 1 (PINK1)-mediated mitophagy were activated in DNP, which was enhanced by HL but not isobaric lidocaine. Blocking p38 MAPK/ERK signaling could effectively attenuate HL-induced spinal nerve injury and inhibit mitophagy. CONCLUSION: In summary, HL can aggravate spinal cord tissue damage in DNP rats by inducing PINK1-mediated mitophagy via activating p38 MAPK/ERK signaling. Our data provide a novel insight that supports the potential role of p38 MAPK/ERK signaling in acting as a therapeutic target for HL-induced neurotoxicity.

KAT8 compound inhibition inhibits the initial steps of PINK1-dependant mitophagy.

It has recently been shown that KAT8, a genome-wide association study candidate risk gene for Parkinson's Disease, is involved in PINK1/Parkin-dependant mitophagy. The KAT8 gene encodes a lysine acetyltransferase and represents the catalytically active subunit of the non-specific lethal epigenetic remodelling complex. In the current study, we show that contrary to KAT5 inhibition, dual inhibition of KAT5 and KAT8 via the MG149 compound inhibits the initial steps of the PINK1-dependant mitophagy process. More specifically, our study shows that following mitochondrial depolarisation induced by mitochondrial toxins, MG149 treatment inhibits PINK1-dependant mitophagy initiation by impairing PINK1 activation, and subsequent phosphorylation of Parkin and ubiquitin. While this inhibitory effect of MG149 on PINK1-activation is potent, MG149 treatment in the absence of mitochondrial toxins is sufficient to depolarise the mitochondrial membrane, recruit PINK1 and promote partial downstream recruitment of the autophagy receptor p62, leading to an increase in mitochondrial delivery to the lysosomes. Altogether, our study provides additional support for KAT8 as a regulator of mitophagy and autophagy processes.

Liquid-liquid phase separation of TZP promotes PPK-mediated phosphorylation of the phytochrome A photoreceptor.

Phytochrome A (phyA) is the plant far-red (FR) light photoreceptor and plays an essential role in regulating photomorphogenic development in FR-rich conditions, such as canopy shade. It has long been observed that phyA is a phosphoprotein in vivo; however, the protein kinases that could phosphorylate phyA remain largely unknown. Here we show that a small protein kinase family, consisting of four members named PHOTOREGULATORY PROTEIN KINASES (PPKs) (also known as MUT9-LIKE KINASES), directly phosphorylate phyA in vitro and in vivo. In addition, TANDEM ZINC-FINGER/PLUS3 (TZP), a recently characterized phyA-interacting protein required for in vivo phosphorylation of phyA, is also directly phosphorylated by PPKs. We reveal that TZP contains two intrinsically disordered regions in its amino-terminal domain that undergo liquid-liquid phase separation (LLPS) upon light exposure. The LLPS of TZP promotes colocalization and interaction between PPKs and phyA, thus facilitating PPK-mediated phosphorylation of phyA in FR light. Our study identifies PPKs as a class of protein kinases mediating the phosphorylation of phyA and demonstrates that the LLPS of TZP contributes significantly to more production of the phosphorylated phyA form in FR light.

Identification of cysteine-rich receptor-like kinase gene family in potato: revealed StCRLK9 in response to heat, salt and drought stresses.

The investigation into cysteine-rich receptor-like kinases (CRLKs) holds pivotal significance as these conserved, upstream signalling molecules intricately regulate fundamental biological processes such as plant growth, development and stress adaptation. This study undertakes a comprehensive characterisation of CRLKs in Solanum tuberosum (potato), a staple food crop of immense economic importance. Employing comparative genomics and evolutionary analyses, we identified 10 distinct CRLK genes in potato. Further categorisation into three major groups based on sequence similarity was performed. Each CRLK member in potato was systematically named according to its chromosomal position. Multiple sequence alignment and phylogenetic analyses unveiled conserved gene structures and motifs within the same groups. The genomic distribution of CRLKs was observed across Chromosomes 2-5, 8 and 12. Gene duplication analysis highlighted a noteworthy trend, with most gene pairs exhibiting a Ka/Ks ratio greater than one, indicating positive selection of StCRLKs in potato. Salt and drought stresses significantly impacted peroxidase and catalase activities in potato seedlings. The presence of diverse cis -regulatory elements, including hormone-responsive elements, underscored their involvement in myriad biotic and abiotic stress responses. Interestingly, interactions between the phytohormone auxin and CRLK proteins unveiled a potential auxin-mediated regulatory mechanism. A holistic approach combining transcriptomics and quantitative PCR validation identified StCRLK9 as a potential candidate involved in plant response to heat, salt and drought stresses. This study lays a robust foundation for future research on the functional roles of the CRLK gene family in potatoes, offering valuable insights into their diverse regulatory mechanisms and potential applications in stress management.

Exploring the neuroprotective role of artesunate in mouse models of anti-NMDAR encephalitis: insights from molecular mechanisms and transmission electron microscopy.

BACKGROUND: The pathway involving PTEN-induced putative kinase 1 (PINK1) and PARKIN plays a crucial role in mitophagy, a process activated by artesunate (ART). We propose that patients with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis exhibit insufficient mitophagy, and ART enhances mitophagy via the PINK1/PARKIN pathway, thereby providing neuroprotection. METHODS: Adult female mice aged 8-10 weeks were selected to create a passive transfer model of anti-NMDAR encephalitis. We conducted behavioral tests on these mice within a set timeframe. Techniques such as immunohistochemistry, immunofluorescence, and western blotting were employed to assess markers including PINK1, PARKIN, LC3B, p62, caspase3, and cleaved caspase3. The TUNEL assay was utilized to detect neuronal apoptosis, while transmission electron microscopy (TEM) was used to examine mitochondrial autophagosomes. Primary hippocampal neurons were cultured, treated, and then analyzed through immunofluorescence for mtDNA, mtROS, TMRM. RESULTS: In comparison to the control group, mitophagy levels in the experimental group were not significantly altered, yet there was a notable increase in apoptotic neurons. Furthermore, markers indicative of mitochondrial leakage and damage were found to be elevated in the experimental group compared to the control group, but these markers showed improvement following ART treatment. ART was effective in activating the PINK1/PARKIN pathway, enhancing mitophagy, and diminishing neuronal apoptosis. Behavioral assessments revealed that ART ameliorated symptoms in mice with anti-NMDAR encephalitis in the passive transfer model (PTM). The knockdown of PINK1 led to a reduction in mitophagy levels, and subsequent ART intervention did not alleviate symptoms in the anti-NMDAR encephalitis PTM mice, indicating that ART's therapeutic efficacy is mediated through the activation of the PINK1/PARKIN pathway. CONCLUSIONS: At the onset of anti-NMDAR encephalitis, mitochondrial damage is observed; however, this damage is mitigated by the activation of mitophagy via the PINK1/PARKIN pathway. This regulatory feedback mechanism facilitates the removal of damaged mitochondria, prevents neuronal apoptosis, and consequently safeguards neural tissue. ART activates the PINK1/PARKIN pathway to enhance mitophagy, thereby exerting neuroprotective effects and may achieve therapeutic goals in treating anti-NMDAR encephalitis.

Mitochondrial transfer mediates endothelial cell engraftment through mitophagy.

Ischaemic diseases such as critical limb ischaemia and myocardial infarction affect millions of people worldwide1. Transplanting endothelial cells (ECs) is a promising therapy in vascular medicine, but engrafting ECs typically necessitates co-transplanting perivascular supporting cells such as mesenchymal stromal cells (MSCs), which makes clinical implementation complicated2,3. The mechanisms that enable MSCs to facilitate EC engraftment remain elusive. Here we show that, under cellular stress, MSCs transfer mitochondria to ECs through tunnelling nanotubes, and that blocking this transfer impairs EC engraftment. We devised a strategy to artificially transplant mitochondria, transiently enhancing EC bioenergetics and enabling them to form functional vessels in ischaemic tissues without the support of MSCs. Notably, exogenous mitochondria did not integrate into the endogenous EC mitochondrial pool, but triggered mitophagy after internalization. Transplanted mitochondria co-localized with autophagosomes, and ablation of the PINK1-Parkin pathway negated the enhanced engraftment ability of ECs. Our findings reveal a mechanism that underlies the effects of mitochondrial transfer between mesenchymal and endothelial cells, and offer potential for a new approach for vascular cell therapy.

Electropositive Citric Acid-Polyethyleneimine Carbon Dots Carrying the PINK1 Gene Regulate ATP-Related Metabolic Dysfunction in APP/PS1-N2a Cells.

(1) Background: Alzheimer's disease (AD) is characterized by ß-amyloid (Aß) peptide accumulation and mitochondrial dysfunction during the early stage of disease. PINK1 regulates the balance between mitochondrial homeostasis and bioenergy supply and demand via the PINK1/Parkin pathway, Na+/Ca2+ exchange, and other pathways. (2) Methods: In this study, we synthesized positively charged carbon dots (CA-PEI CDs) using citric acid (CA) and polyethyleneimine (PEI) and used them as vectors to express PINK1 genes in the APP/PS1-N2a cell line to determine mitochondrial function, electron transport chain (ETC) activity, and ATP-related metabolomics. (3) Results: Our findings showed that the CA-PEI CDs exhibit the characteristics of photoluminescence, low toxicity, and concentrated DNA. They are ideal biological carriers for gene delivery. PINK1 overexpression significantly increased the mitochondrial membrane potential in APP/PS1-N2a cells and reduced reactive-oxygen-species generation and Aß1-40 and Aß1-42 levels. An increase in the activity of NADH ubiquinone oxidoreductase (complex I, CI) and cytochrome C oxidase (complex IV, CIV) induces the oxidative phosphorylation of mitochondria, increasing ATP generation. (4) Conclusions: These findings indicate that the PINK gene can alleviate AD by increasing bioenergetic metabolism, reducing Aß1-40 and Aß1-42, and increasing ATP production.

Acetylation and Phosphorylation Regulate the Role of Pyruvate Kinase as a Glycolytic Enzyme or a Protein Kinase in Lamb.

Protein post-translational modifications (PTMs) play an essential role in meat quality development. However, the effect of specific PTM sites on meat proteins has not been investigated yet. The characteristics of pyruvate kinase M (PKM) were found to exhibit a close correlation with final meat quality, and thus, serine 99 (S99) and lysine 137 (K137) in PKM were mutated to study their effect on PKM function. The structural and functional properties of five lamb PKM variants, including wild-type PKM (wtPKM), PKM_S99D (S99 phosphorylation), PKM_S99A (PKM S99 dephosphorylation), PKM_K137Q (PKM K137 acetylation), and PKM_K137R (PKM K137 deacetylation), were evaluated. The results showed that the secondary structure, tertiary structure, and polymer formation were affected among different PKM variants. In addition, the glycolytic activity of PKM_K137Q was decreased because of its weakened binding with phosphoenolpyruvate. In the PKM_K137R variant, the actin phosphorylation level exhibited a decrease, suggesting a low kinase activity of PKM_K137R. The results of molecular simulation showed a 42% reduction in the interface area between PKM_K137R and actin, in contrast to wtPKM and actin. These findings are significant for revealing the mechanism of how PTMs regulate PKM function and provide a theoretical foundation for the development of precise meat quality preservation technology.

Comprehensive analysis of stress-activated protein kinase genes (OsSAPKs) in rice flowering time.

MAIN CONCLUSION: The rice SnRK2 members SAPK4, SAPK5, SAPK7 and SAPK10 are positive regulators involved in the regulation of rice flowering, while other single mutants exhibited no effect on rice flowering. The rice SnRK2 family, comprising 10 members known as SAPK (SnRK2-Associated Protein Kinase), is pivotal in the abscisic acid (ABA) pathway and crucial for various biological processes, such as drought resistance and salt tolerance. Additionally, these members have been implicated in the regulation of rice heading date, a key trait influencing planting area and yield. In this study, we utilized gene editing technology to create mutants in the Songjing 2 (SJ2) background, enabling a comprehensive analyze the role of each SAPK member in rice flowering. We found that SAPK1, SAPK2, and SAPK3 may not directly participate in the regulatory network of rice heading date, while SAPK4, SAPK5, and SAPK7 play positive roles in rice flowering regulation. Notably, polygene deletion resulted in an additive effect on delaying flowering. Our findings corroborate the previous studies indicating the positive regulatory role of SAPK10 in rice flowering, as evidenced by delayed flowering observed in sapk9/10 double mutants. Moving forward, our future research will focus on analyzing the molecular mechanisms underlying SAPKs involvement in rice flowering regulation, aiming to enhance our understanding of the rice heading date relationship network and lay a theoretical foundation for breeding efforts to alter rice ripening dates.

Acupotomy alleviates knee osteoarthritis in rabbit by regulating chondrocyte mitophagy Pink1-Parkin pathway.

OBJECTIVE: To investigate the effect of acupotomy, on mitophagy and the Pink1-Parkin pathway in chondrocytes from rabbits with knee osteoarthritis (KOA). METHODS: A KOA model was established via the modified Videman method. Rabbits were randomly divided into a control group (CON), KOA group and KOA + acupotomy group (Acu). Rabbits in the acupotomy group were subjected to acupotomy for 4 weeks after model establishment. The behavior of the rabbits before and after intervention was recorded. Cartilage degeneration was evaluated by optical microscopy and fluorescence microscopy. The level of mitophagy was evaluated by transmission electron microscopy, immunofluorescence and enzyme-linked immunosorbent assay (ELISA). The expression of phosphatase and tensin homolog (PTEN)-induced kinase 1 (Pink1)-Parkin mitophagy pathway components was evaluated by immunofluorescence, Western blotting and real-time polymerase chain reaction. RESULTS: In rabbits with KOA, joint pain, mobility disorders and cartilage degeneration were observed, the Mankin score was increased, collagen type Ⅱ (Col-Ⅱ) expression was significantly decreased, mitophagy was inhibited, mitochondrial function was impaired, and factors associated with the Pink1-Parkin pathway were inhibited. Acupotomy regulated the expression of Pink1-Parkin pathway-related proteins, the mitophagy-related protein microtubule-associated protein-1 light chain-3, the translocase of the outer membrane, and the inner mitochondrial membrane 23; increased the colocalization of mitochondria and autophagosomes; promoted the removal of damaged mitochondria; restored mitochondrial adenosine-triphosphate (ATP) production; and alleviated cartilage degeneration in rabbits with KOA. CONCLUSIONS: Acupotomy played a role in alleviating KOA in rabbits by activating mitophagy in chondrocytes via the regulation of proteins that are related to the Pink1-Parkin pathway.

Gaining Insights into Key Structural Hotspots within the Allosteric Binding Pockets of Protein Kinases.

Protein kinases are essential regulators of cell function and represent one of the largest and most diverse protein families. They are particularly influential in signal transduction and coordinating complex processes like the cell cycle. Out of the 518 human protein kinases identified, 478 are part of a single superfamily sharing catalytic domains that are related in sequence. The dysregulation of protein kinases due to certain mutations has been associated with various diseases, including cancer. Although most of the protein kinase inhibitors identified as type I or type II primarily target the ATP-binding pockets of kinases, the structural and sequential resemblances among these pockets pose a significant challenge for selective inhibition. Therefore, targeting allosteric pockets that are beside highly conserved ATP pockets has emerged as a promising strategy to prevail current limitations, such as poor selectivity and drug resistance. In this article, we compared the binding pockets of various protein kinases for which allosteric (type III) inhibitors have already been developed. Additionally, understanding the structure and shape of existing ligands could aid in identifying key interaction sites within the allosteric pockets of kinases. This comprehensive review aims to facilitate the design of more effective and selective allosteric inhibitors.

VDR restores the expression of PINK1 and BNIP3 in TECs of streptozotocin-induced diabetic mice.

Defective mitophagy in renal tubular epithelial cells is one of the main drivers of renal fibrosis in diabetic kidney disease. Our gene sequencing data showed the expression of PINK1 and BNIP3, two key molecules of mitophagy, was decreased in renal tissues of VDR-knockout mice. Herein, streptozotocin (STZ) was used to induce renal interstitial fibrosis in mice. VDR deficiency exacerbated STZ-induced renal impairment and defective mitophagy. Paricalcitol (pari, a VDR agonist) and the tubular epithelial cell-specific overexpression of VDR restored the expression of PINK1 and BNIP3 in the renal cortex and attenuated STZ-induced kidney fibrosis and mitochondrial dysfunction. In HK-2 cells under high glucose conditions, an increased level of α-SMA, COL1, and FN and a decreased expression of PINK1 and BNIP3 with severe mitochondrial damage were observed, and these alterations could be largely reversed by pari treatment. ChIP-qPCR and luciferase reporter assays showed VDR could positively regulate the transcription of Pink1 and Bnip3 genes. These findings reveal that VDR could restore mitophagy defects and attenuate STZ-induced fibrosis in diabetic mice through regulation of PINK1 and BNIP3.

Melatonin Ameliorates Post-Stroke Cognitive Impairment in Mice by Inhibiting Excessive Mitophagy.

Post-stroke cognitive impairment (PSCI) remains the most common consequence of ischemic stroke. In this study, we aimed to investigate the role and mechanisms of melatonin (MT) in improving cognitive dysfunction in stroke mice. We used CoCl2-induced hypoxia-injured SH-SY5Y cells as a cellular model of stroke and photothrombotic-induced ischemic stroke mice as an animal model. We found that the stroke-induced upregulation of mitophagy, apoptosis, and neuronal synaptic plasticity was impaired both in vivo and in vitro. The results of the novel object recognition test and Y-maze showed significant cognitive deficits in the stroke mice, and Nissl staining showed a loss of neurons in the stroke mice. In contrast, MT inhibited excessive mitophagy both in vivo and in vitro and decreased the levels of mitophagy proteins PINK1 and Parkin, and immunofluorescence staining showed reduced co-localization of Tom20 and LC3. A significant inhibition of mitophagy levels could be directly observed under transmission electron microscopy. Furthermore, behavioral experiments and Nissl staining showed that MT ameliorated cognitive deficits and reduced neuronal loss in mice following a stroke. Our results demonstrated that MT inhibits excessive mitophagy and improves PSCI. These findings highlight the potential of MT as a preventive drug for PSCI, offering promising therapeutic implications.

Guided Docking as a Data Generation Approach Facilitates Structure-Based Machine Learning on Kinases.

Drug discovery pipelines nowadays rely on machine learning models to explore and evaluate large chemical spaces. While including 3D structural information is considered beneficial, structural models are hindered by the availability of protein-ligand complex structures. Exemplified for kinase drug discovery, we address this issue by generating kinase-ligand complex data using template docking for the kinase compound subset of available ChEMBL assay data. To evaluate the benefit of the created complex data, we use it to train a structure-based E(3)-invariant graph neural network. Our evaluation shows that binding affinities can be predicted with significantly higher precision by models that take synthetic binding poses into account compared to ligand- or drug-target interaction models alone.

Receptor-like cytoplasmic kinases of different subfamilies differentially regulate SOBIR1/BAK1-mediated immune responses in Nicotiana benthamiana.

Cell-surface receptors form the front line of plant immunity. The leucine-rich repeat (LRR)-receptor-like kinases SOBIR1 and BAK1 are required for the functionality of the tomato LRR-receptor-like protein Cf-4, which detects the secreted effector Avr4 of the pathogenic fungus Fulvia fulva. Here, we show that the kinase domains of SOBIR1 and BAK1 directly phosphorylate each other and that residues Thr522 and Tyr469 of the kinase domain of Nicotiana benthamiana SOBIR1 are required for its kinase activity and for interacting with signalling partners, respectively. By knocking out multiple genes belonging to different receptor-like cytoplasmic kinase (RLCK)-VII subfamilies in N. benthamiana:Cf-4, we show that members of RLCK-VII-6, -7, and -8 differentially regulate the Avr4/Cf-4-triggered biphasic burst of reactive oxygen species. In addition, members of RLCK-VII-7 play an essential role in resistance against the oomycete pathogen Phytophthora palmivora. Our study provides molecular evidence for the specific roles of RLCKs downstream of SOBIR1/BAK1-containing immune complexes.

Bioinformatics analysis of PANoptosis regulators in the diagnosis and subtyping of steroid-induced osteonecrosis of the femoral head.

In this study, we aimed to investigate the involvement of PANoptosis, a form of regulated cell death, in the development of steroid-induced osteonecrosis of the femoral head (SONFH). The underlying pathogenesis of PANoptosis in SONFH remains unclear. To address this, we employed bioinformatics approaches to analyze the key genes associated with PANoptosis. Our analysis was based on the GSE123568 dataset, allowing us to investigate both the expression profiles of PANoptosis-related genes (PRGs) and the immune profiles in SONFHallowing us to investigate the expression profiles of PRGs as well as the immune profiles in SONFH. We conducted cluster classification based on PRGs and assessed immune cell infiltration. Additionally, we used the weighted gene co-expression network analysis (WGCNA) algorithm to identify cluster-specific hub genes. Furthermore, we developed an optimal machine learning model to identify the key predictive genes responsible for SONFH progression. We also constructed a nomogram model with high predictive accuracy for assessing risk factors in SONFH patients, and validated the model using external data (area under the curve; AUC = 1.000). Furthermore, we identified potential drug targets for SONFH through the Coremine medical database. Using the optimal machine learning model, we found that 2 PRGs, CASP1 and MLKL, were significantly correlated with the key predictive genes and exhibited higher expression levels in SONFH. Our analysis revealed the existence of 2 distinct PANoptosis molecular subtypes (C1 and C2) within SONFH. Importantly, we observed significant variations in the distribution of immune cells across these subtypes, with C2 displaying higher levels of immune cell infiltration. Gene set variation analysis indicated that C2 was closely associated with multiple immune responses. In conclusion, our study sheds light on the intricate relationship between PANoptosis and SONFH. We successfully developed a risk predictive model for SONFH patients and different SONFH subtypes. These findings enhance our understanding of the pathogenesis of SONFH and offer potential insights into therapeutic strategies.

KdpD is a tandem serine histidine kinase that controls K+ pump KdpFABC transcriptionally and post-translationally.

Two-component systems, consisting of a histidine kinase and a response regulator, serve signal transduction in bacteria, often regulating transcription in response to environmental stimuli. Here, we identify a tandem serine histidine kinase function for KdpD, previously described as a histidine kinase of the KdpDE two-component system, which controls production of the potassium pump KdpFABC. We show that KdpD additionally mediates an inhibitory serine phosphorylation of KdpFABC at high potassium levels, using not its C-terminal histidine kinase domain but an N-terminal atypical serine kinase domain. Sequence analysis of KdpDs from different species highlights that some KdpDs are much shorter than others. We show that, while Escherichia coli KdpD's atypical serine kinase domain responds directly to potassium levels, a shorter version from Deinococcus geothermalis is controlled by second messenger cyclic di-AMP. Our findings add to the growing functional diversity of sensor kinases while simultaneously expanding the framework for regulatory mechanisms in bacterial potassium homeostasis.

The mitochondria-targeted antioxidant MitoQ ameliorates inorganic arsenic-induced DCs/Th1/Th2/Th17/Treg differentiation partially by activating PINK1-mediated mitophagy in murine liver.

Inorganic arsenic is a well-established environmental toxicant linked to acute liver injury, fibrosis, and cancer. While oxidative stress, pyroptosis, and ferroptosis are known contributors, the role of PTEN-induced kinase 1 (PINK1)-mediated mitophagy in arsenic-induced hepatic immunotoxicity remains underexplored. Our study revealed that acute arsenic exposure prompts differentiation of hepatic dendritic cells (DCs) and T helper (Th) 1, Th2, Th17, and regulatory T (Treg) cells, alongside increased transcription factors and cytokines. Inorganic arsenic triggered liver redox imbalance, leading to elevated alanine transaminase (ALT), hydrogen peroxide (H2O2), malondialdehyde (MDA), and activation of nuclear factor erythroid 2-related factor (Nrf2)/heme oxygenase-1 (HO-1) pathway. PINK1-mediated mitophagy was initiated, and its inhibition exacerbates H2O2 accumulation while promoting DCs/Th1/Th2/Treg differentiation in the liver of arsenic-exposed mice. Mitoquinone (MitoQ) pretreatment relieved arsenic-induced acute liver injury and immune imbalance by activating Nrf2/HO-1 and PINK1-mediated mitophagy. To our knowledge, this is the first report identifying PINK1-mediated mitophagy as a protective factor against inorganic arsenic-induced hepatic DCs/Th1/Th2 differentiation. This study has provided new insights on the immunotoxicity of inorganic arsenic and established a foundation for exploring preventive and therapeutic strategies targeting PINK1-mediated mitophagy in acute liver injury. Consequently, the application of mitochondrial antioxidant MitoQ may offer a promising treatment for the metalloid-induced acute liver injury.