Closing the loops: chromatin loop dynamics after DNA damage

Chromatin is a dynamic polymer in constant motion. These motions are heterogeneous between cells and within individual cell nuclei and are profoundly altered in response to DNA damage. The shifts in chromatin motions following genomic insults depend on the temporal and physical scales considered. They are also distinct in damaged and undamaged regions. In this review, we emphasize the role of chromatin tethering and loop formation in chromatin dynamics, with the view that pulsing loops are key contributors to chromatin motions. Chromatin tethers likely mediate micron-scale chromatin coherence predicted by polymer models and measured experimentally, and we propose that remodeling of the tethers in response to DNA breaks enables uncoupling of damaged and undamaged chromatin regions.

tRNA modifications: greasing the wheels of translation and beyond

Transfer RNA (tRNA) is one of the most abundant RNA types in cells, acting as an adaptor to bridge the genetic information in mRNAs with the amino acid sequence in proteins. Both tRNAs and small fragments processed from them play many nonconventional roles in addition to translation. tRNA molecules undergo various types of chemical modifications to ensure the accuracy and efficiency of translation and regulate their diverse functions beyond translation. In this review, we discuss the biogenesis and molecular mechanisms of tRNA modifications, including major tRNA modifications, writer enzymes, and their dynamic regulation. We also summarize the state-of-the-art technologies for measuring tRNA modification, with a particular focus on 2'-O-methylation (Nm), and discuss their limitations and remaining challenges. Finally, we highlight recent discoveries linking dysregulation of tRNA modifications with genetic diseases.

RNA-binding protein quaking: a multifunctional regulator in tumour progression

BACKGROUND

Quaking (QKI) is a member of the signal transduction and activators of RNA (STAR) family, performing a crucial multifunctional regulatory role in alternative splicing, mRNA precursor processing, mRNA transport and localization, mRNA stabilization, and translation during tumour progression. Abnormal QKI expression or fusion mutations lead to aberrant RNA and protein expression, thereby promoting tumour progression. However, in many types of tumour, QKI played a role as tumour suppressor, the regulatory role of QKI in tumour progression remains ambiguous.

OBJECTIVES

This review aims to analyze the isoform and function of QKI, the impact of QKI-regulated gene expression or signalling pathway alterations on tumour progression, and its potential clinical applications as a predictive marker or target for tumour therapy.

METHODS

We reviewed recent studies and summarized the function of QKI alteration in tumour progression.

RESULTS

QKI mediate post-transcriptional gene regulation including alternative splicing, polyadenylation, mRNA stabilization, mRNA subcellular location, and noncoding RNA by binding to the QRE elements of targeted nucleotide. The dysregulation of QKI is intricately correlated to tumour proliferation, metastasis, angiogenesis, tumor stem cells, the tumour microenvironment, and treatment sensitivity, and represents as a potential biological predictor in tumour diagnosis and prognosis.

CONCLUSIONS

QKI play a critical role as tumour suppressor or an oncogene in tumour progression due to the different splicing sites and transcripts with various tumour subtype or tumor micorenvironment. Ongoing research about QKI's functions and mechanisms persist is required to conduct for better understanding the role of QKI in tumour regulation.

Crosstalk among canonical Wnt and Hippo pathway members in skeletal muscle and at the neuromuscular junction

Skeletal muscles are essential for locomotion, posture, and metabolic regulation. To understand physiological processes, exercise adaptation, and muscle-related disorders, it is critical to understand the molecular pathways that underlie skeletal muscle function. The process of muscle contraction, orchestrated by a complex interplay of molecular events, is at the core of skeletal muscle function. Muscle contraction is initiated by an action potential and neuromuscular transmission requiring a neuromuscular junction. Within muscle fibers, calcium ions play a critical role in mediating the interaction between actin and myosin filaments that generate force. Regulation of calcium release from the sarcoplasmic reticulum plays a key role in excitation-contraction coupling. The development and growth of skeletal muscle are regulated by a network of molecular pathways collectively known as myogenesis. Myogenic regulators coordinate the differentiation of myoblasts into mature muscle fibers. Signaling pathways regulate muscle protein synthesis and hypertrophy in response to mechanical stimuli and nutrient availability. Several muscle-related diseases, including congenital myasthenic disorders, sarcopenia, muscular dystrophies, and metabolic myopathies, are underpinned by dysregulated molecular pathways in skeletal muscle. Therapeutic interventions aimed at preserving muscle mass and function, enhancing regeneration, and improving metabolic health hold promise by targeting specific molecular pathways. Other molecular signaling pathways in skeletal muscle include the canonical Wnt signaling pathway, a critical regulator of myogenesis, muscle regeneration, and metabolic function, and the Hippo signaling pathway. In recent years, more details have been uncovered about the role of these two pathways during myogenesis and in developing and adult skeletal muscle fibers, and at the neuromuscular junction. In fact, research in the last few years now suggests that these two signaling pathways are interconnected and that they jointly control physiological and pathophysiological processes in muscle fibers. In this review, we will summarize and discuss the data on these two pathways, focusing on their concerted action next to their contribution to skeletal muscle biology. However, an in-depth discussion of the non-canonical Wnt pathway, the fibro/adipogenic precursors, or the mechanosensory aspects of these pathways is not the focus of this review.

Mitophagy in acute central nervous system injuries: regulatory mechanisms and therapeutic potentials

Acute central nervous system injuries, including ischemic stroke, intracerebral hemorrhage, subarachnoid hemorrhage, traumatic brain injury, and spinal cord injury, are a major global health challenge. Identifying optimal therapies and improving the long-term neurological functions of patients with acute central nervous system injuries are urgent priorities. Mitochondria are susceptible to damage after acute central nervous system injury, and this leads to the release of toxic levels of reactive oxygen species, which induce cell death. Mitophagy, a selective form of autophagy, is crucial in eliminating redundant or damaged mitochondria during these events. Recent evidence has highlighted the significant role of mitophagy in acute central nervous system injuries. In this review, we provide a comprehensive overview of the process, classification, and related mechanisms of mitophagy. We also highlight the recent developments in research into the role of mitophagy in various acute central nervous system injuries and drug therapies that regulate mitophagy. In the final section of this review, we emphasize the potential for treating these disorders by focusing on mitophagy and suggest future research paths in this area.

Neuronal regulated cell death in aging-related neurodegenerative diseases: key pathways and therapeutic potentials

Regulated cell death (such as apoptosis, necroptosis, pyroptosis, autophagy, cuproptosis, ferroptosis, disulfidptosis) involves complex signaling pathways and molecular effectors, and has been proven to be an important regulatory mechanism for regulating neuronal aging and death. However, excessive activation of regulated cell death may lead to the progression of aging-related diseases. This review summarizes recent advances in the understanding of seven forms of regulated cell death in age-related diseases. Notably, the newly identified ferroptosis and cuproptosis have been implicated in the risk of cognitive impairment and neurodegenerative diseases. These forms of cell death exacerbate disease progression by promoting inflammation, oxidative stress, and pathological protein aggregation. The review also provides an overview of key signaling pathways and crosstalk mechanisms among these regulated cell death forms, with a focus on ferroptosis, cuproptosis, and disulfidptosis. For instance, FDX1 directly induces cuproptosis by regulating copper ion valency and dihydrolipoamide S-acetyltransferase aggregation, while copper mediates glutathione peroxidase 4 degradation, enhancing ferroptosis sensitivity. Additionally, inhibiting the Xc- transport system to prevent ferroptosis can increase disulfide formation and shift the NADP + /NADPH ratio, transitioning ferroptosis to disulfidptosis. These insights help to uncover the potential connections among these novel regulated cell death forms and differentiate them from traditional regulated cell death mechanisms. In conclusion, identifying key targets and their crosstalk points among various regulated cell death pathways may aid in developing specific biomarkers to reverse the aging clock and treat age-related neurodegenerative conditions.

CNKSR2 interactome analysis indicates its association with the centrosome/microtubule system

JOURNAL/nrgr/04.03/01300535-202508000-00031/figure1/v/2024-09-30T120553Z/r/image-tiff The protein connector enhancer of kinase suppressor of Ras 2 (CNKSR2), present in both the postsynaptic density and cytoplasm of neurons, is a scaffolding protein with several protein-binding domains. Variants of the CNKSR2 gene have been implicated in neurodevelopmental disorders, particularly intellectual disability, although the precise mechanism involved has not yet been fully understood. Research has demonstrated that CNKSR2 plays a role in facilitating the localization of postsynaptic density protein complexes to the membrane, thereby influencing synaptic signaling and the morphogenesis of dendritic spines. However, the function of CNKSR2 in the cytoplasm remains to be elucidated. In this study, we used immunoprecipitation and high-resolution liquid chromatography-mass spectrometry to identify the interactors of CNKSR2. Through a combination of bioinformatic analysis and cytological experiments, we found that the CNKSR2 interactors were significantly enriched in the proteome of the centrosome. We also showed that CNKSR2 interacted with the microtubule protein DYNC1H1 and with the centrosome marker CEP290. Subsequent colocalization analysis confirmed the centrosomal localization of CNKSR2. When we downregulated CNKSR2 expression in mouse neuroblastoma cells (Neuro 2A), we observed significant changes in the expression of numerous centrosomal genes. This manipulation also affected centrosome-related functions, including cell size and shape, cell proliferation, and motility. Furthermore, we found that CNKSR2 interactors were highly enriched in de novo variants associated with intellectual disability and autism spectrum disorder. Our findings establish a connection between CNKSR2 and the centrosome, and offer new insights into the underlying mechanisms of neurodevelopmental disorders.

Interaction of major facilitator superfamily domain containing 2A with the blood-brain barrier

The functional and structural integrity of the blood-brain barrier is crucial in maintaining homeostasis in the brain microenvironment; however, the molecular mechanisms underlying the formation and function of the blood-brain barrier remain poorly understood. The major facilitator superfamily domain containing 2A has been identified as a key regulator of blood-brain barrier function. It plays a critical role in promoting and maintaining the formation and functional stability of the blood-brain barrier, in addition to the transport of lipids, such as docosahexaenoic acid, across the blood-brain barrier. Furthermore, an increasing number of studies have suggested that major facilitator superfamily domain containing 2A is involved in the molecular mechanisms of blood-brain barrier dysfunction in a variety of neurological diseases; however, little is known regarding the mechanisms by which major facilitator superfamily domain containing 2A affects the blood-brain barrier. This paper provides a comprehensive and systematic review of the close relationship between major facilitator superfamily domain containing 2A proteins and the blood-brain barrier, including their basic structures and functions, cross-linking between major facilitator superfamily domain containing 2A and the blood-brain barrier, and the in-depth studies on lipid transport and the regulation of blood-brain barrier permeability. This comprehensive systematic review contributes to an in-depth understanding of the important role of major facilitator superfamily domain containing 2A proteins in maintaining the structure and function of the blood-brain barrier and the research progress to date. This will not only help to elucidate the pathogenesis of neurological diseases, improve the accuracy of laboratory diagnosis, and optimize clinical treatment strategies, but it may also play an important role in prognostic monitoring. In addition, the effects of major facilitator superfamily domain containing 2A on blood-brain barrier leakage in various diseases and the research progress on cross-blood-brain barrier drug delivery are summarized. This review may contribute to the development of new approaches for the treatment of neurological diseases.

MicroRNAs as potential biomarkers for diagnosis of post-traumatic stress disorder

Post-traumatic stress disorder is a mental disorder caused by exposure to severe traumatic life events. Currently, there are no validated biomarkers or laboratory tests that can distinguish between trauma survivors with and without post-traumatic stress disorder. In addition, the heterogeneity of clinical presentations of post-traumatic stress disorder and the overlap of symptoms with other conditions can lead to misdiagnosis and inappropriate treatment. Evidence suggests that this condition is a multisystem disorder that affects many biological systems, raising the possibility that peripheral markers of disease may be used to diagnose post-traumatic stress disorder. We performed a PubMed search for microRNAs (miRNAs) in post-traumatic stress disorder (PTSD) that could serve as diagnostic biomarkers and found 18 original research articles on studies performed with human patients and published January 2012 to December 2023. These included four studies with whole blood, seven with peripheral blood mononuclear cells, four with plasma extracellular vesicles/exosomes, and one with serum exosomes. One of these studies had also used whole plasma. Two studies were excluded as they did not involve microRNA biomarkers. Most of the studies had collected samples from adult male Veterans who had returned from deployment and been exposed to combat, and only two were from recently traumatized adult subjects. In measuring miRNA expression levels, many of the studies had used microarray miRNA analysis, miRNA Seq analysis, or NanoString panels. Only six studies had used real time polymerase chain reaction assay to determine/validate miRNA expression in PTSD subjects compared to controls. The miRNAs that were found/validated in these studies may be considered as potential candidate biomarkers for PTSD and include miR-3130-5p in whole blood; miR-193a-5p, -7113-5p, -125a, -181c, and -671-5p in peripheral blood mononuclear cells; miR-10b-5p, -203a-3p, -4488, -502-3p, -874-3p, -5100, and -7641 in plasma extracellular vesicles/exosomes; and miR-18a-3p and -7-1-5p in blood plasma. Several important limitations identified in the studies need to be taken into account in future studies. Further studies are warranted with war veterans and recently traumatized children, adolescents, and adults having PTSD and use of animal models subjected to various stressors and the effects of suppressing or overexpressing specific microRNAs.

Autophagy-targeting modulation to promote peripheral nerve regeneration

Nerve regeneration following traumatic peripheral nerve injuries and neuropathies is a complex process modulated by diverse factors and intricate molecular mechanisms. Past studies have focused on factors that stimulate axonal outgrowth and myelin regeneration. However, recent studies have highlighted the pivotal role of autophagy in peripheral nerve regeneration, particularly in the context of traumatic injuries. Consequently, autophagy-targeting modulation has emerged as a promising therapeutic approach to enhancing peripheral nerve regeneration. Our current understanding suggests that activating autophagy facilitates the rapid clearance of damaged axons and myelin sheaths, thereby enhancing neuronal survival and mitigating injury-induced oxidative stress and inflammation. These actions collectively contribute to creating a favorable microenvironment for structural and functional nerve regeneration. A range of autophagy-inducing drugs and interventions have demonstrated beneficial effects in alleviating peripheral neuropathy and promoting nerve regeneration in preclinical models of traumatic peripheral nerve injuries. This review delves into the regulation of autophagy in cell types involved in peripheral nerve regeneration, summarizing the potential drugs and interventions that can be harnessed to promote this process. We hope that our review will offer novel insights and perspectives on the exploitation of autophagy pathways in the treatment of peripheral nerve injuries and neuropathies.

New aspects of a small GTPase RAB35 in brain development and function

In eukaryotic cells, organelles in the secretory, lysosomal, and endocytic pathways actively exchange biological materials with each other through intracellular membrane trafficking, which is the process of transporting the cargo of proteins, lipids, and other molecules to appropriate compartments via transport vesicles or intermediates. These processes are strictly regulated by various small GTPases such as the RAS-like in rat brain (RAB) protein family, which is the largest subfamily of the RAS superfamily. Dysfunction of membrane trafficking affects tissue homeostasis and leads to a wide range of diseases, including neurological disorders and neurodegenerative diseases. Therefore, it is important to understand the physiological and pathological roles of RAB proteins in brain function. RAB35, a member of the RAB family, is an evolutionarily conserved protein in metazoans. A wide range of studies using cultured mammalian cells and model organisms have revealed that RAB35 mediates various processes such as cytokinesis, endocytic recycling, actin bundling, and cell migration. RAB35 is also involved in neurite outgrowth and turnover of synaptic vesicles. We generated brain-specific Rab35 knockout mice to study the physiological roles of RAB35 in brain development and function. These mice exhibited defects in anxiety-related behaviors and spatial memory. Strikingly, RAB35 is required for the precise positioning of pyramidal neurons during hippocampal development, and thereby for normal hippocampal lamination. In contrast, layer formation in the cerebral cortex occurred superficially, even in the absence of RAB35, suggesting a predominant role for RAB35 in hippocampal development rather than in cerebral cortex development. Recent studies have suggested an association between RAB35 and neurodegenerative diseases, including Parkinson's disease and Alzheimer's disease. In this review, we provide an overview of the current understanding of subcellular functions of RAB35. We also provide insights into the physiological role of RAB35 in mammalian brain development and function, and discuss the involvement of RAB35 dysfunction in neurodegenerative diseases.

Activation of the mitochondrial unfolded protein response regulates the dynamic formation of stress granules

To rapidly adapt to harmful changes to their environment, cells activate the integrated stress response (ISR). This results in an adaptive transcriptional and translational rewiring, and the formation of biomolecular condensates named stress granules (SGs), to resolve stress. In addition to this first line of defence, the mitochondrial unfolded protein response (UPRmt) activates a specific transcriptional programme to maintain mitochondrial homeostasis. We present evidence that the SG formation and UPRmt pathways are intertwined and communicate. UPRmt induction results in eIF2α phosphorylation and the initial and transient formation of SGs, which subsequently disassemble. The induction of GADD34 (also known as PPP1R15A) during late UPRmt protects cells from prolonged stress by impairing further assembly of SGs. Furthermore, mitochondrial functions and cellular survival are enhanced during UPRmt activation when SGs are absent, suggesting that UPRmt-induced SGs have an adverse effect on mitochondrial homeostasis. These findings point to a novel crosstalk between SGs and the UPRmt that might contribute to restoring mitochondrial functions under stressful conditions.

Rescue of mitochondrial dysfunction through alteration of extracellular matrix composition in barth syndrome cardiac fibroblasts

Fibroblast-ECM (dys)regulation is associated with a plethora of diseases. The ECM acts as a reservoir of inflammatory factors and cytokines that mediate molecular mechanisms within cardiac cell populations. The role of ECM-mitochondria crosstalk in the development and progression of cardiac disorders remains uncertain. We evaluated the influence of ECM produced by stromal cells from patients with the mitochondrial cardiomyopathy (Barth syndrome, BTHS) and unaffected healthy controls on cardiac fibroblast (CF) metabolic function. To do this, cell-derived matrices CDMs were generated from BTHS and healthy human pluripotent stem cell-derived CFs (hPSC-CF) and used as cell culture substrates. BTHS CDMs negatively impacted the mitochondrial function of healthy hPSC-CFs while healthy CDMs improved mitochondrial function in BTHS hPSC-CFs. Mass spectrometry comparisons identified 5 matrisome proteins differentially expressed in BTHS compared to healthy CDM. Our results highlight a key role for the ECM in disease through its impact on mitochondrial function.

Gut microbiota-astrocyte axis: new insights into age-related cognitive decline

With the rapidly aging human population, age-related cognitive decline and dementia are becoming increasingly prevalent worldwide. Aging is considered the main risk factor for cognitive decline and acts through alterations in the composition of the gut microbiota, microbial metabolites, and the functions of astrocytes. The microbiota-gut-brain axis has been the focus of multiple studies and is closely associated with cognitive function. This article provides a comprehensive review of the specific changes that occur in the composition of the gut microbiota and microbial metabolites in older individuals and discusses how the aging of astrocytes and reactive astrocytosis are closely related to age-related cognitive decline and neurodegenerative diseases. This article also summarizes the gut microbiota components that affect astrocyte function, mainly through the vagus nerve, immune responses, circadian rhythms, and microbial metabolites. Finally, this article summarizes the mechanism by which the gut microbiota-astrocyte axis plays a role in Alzheimer's and Parkinson's diseases. Our findings have revealed the critical role of the microbiota-astrocyte axis in age-related cognitive decline, aiding in a deeper understanding of potential gut microbiome-based adjuvant therapy strategies for this condition.

Selective regulation of kinesin-5 function by β-tubulin carboxy-terminal tails

The tubulin code hypothesis predicts that tubulin tails create programs for selective regulation of microtubule-binding proteins, including kinesin motors. However, the molecular mechanisms that determine selective regulation and their relevance in cells are poorly understood. We report selective regulation of budding yeast kinesin-5 motors by the β-tubulin tail. Cin8, but not Kip1, requires the β-tubulin tail for recruitment to the mitotic spindle, creating a balance of both motors in the spindle and efficient mitotic progression. We identify a negatively charged patch in the β-tubulin tail that mediates interaction with Cin8. Using in vitro reconstitution with genetically modified yeast tubulin, we demonstrate that the charged patch of β-tubulin tail increases Cin8 plus-end-directed velocity and processivity. Finally, we determine that the positively charged amino-terminal extension of Cin8 coordinates interactions with the β-tubulin tail. Our work identifies a molecular mechanism underlying selective regulation of closely related kinesin motors by tubulin tails and how this regulation promotes proper function of the mitotic spindle.

CCDC134 controls TLR biogenesis through the ER chaperone Gp96

Toll-like receptors (TLRs) are central to initiate immune responses against invading pathogens. To ensure host defense while avoiding aberrant activation leading to pathogenic inflammation and autoimmune diseases, TLRs are tightly controlled by multilevel regulatory mechanisms. Through a loss-of-function genetic screen in a reporter cell line engineered to undergo cell death upon TLR7-induced IRF5 activation, we identified here CCDC134 as an essential factor for TLR responses. CCDC134 deficiency impaired endolysosomal TLR-induced NF-κB, MAPK, and IRF5 activation, as well as downstream production of proinflammatory cytokines and type I interferons. We further demonstrated that CCDC134 is an endoplasmic reticulum (ER)-resident interactor of Gp96 (HSP90B1/Grp94), an ER chaperone essential for folding and trafficking of plasma membrane and endolysosomal TLRs. CCDC134 controlled Gp96 stability as its loss led to Gp96 hyperglycosylation and ER-associated protein degradation (ERAD)-mediated clearance. Accordingly, CCDC134 deficiency impaired the folding, maturation, and trafficking of TLRs, resulting in blunted inflammatory responses upon stimulation. Altogether, this study reveals CCDC134 as a central regulator of the chaperone Gp96, thereby controlling TLR biogenesis and responses.

An interkinetic envelope surrounds chromosomes between meiosis I and II in C. elegans oocytes

At the end of cell division, the nuclear envelope reassembles around the decondensing chromosomes. Female meiosis culminates in two consecutive cell divisions of the oocyte, meiosis I and II, which are separated by a brief transition phase known as interkinesis. Due to the absence of chromosome decondensation and the suppression of genome replication during interkinesis, it has been widely assumed that the nuclear envelope does not reassemble between meiosis I and II. By analyzing interkinesis in C. elegans oocytes, we instead show that an atypical structure made of two lipid bilayers, which we termed the interkinetic envelope, surrounds the surface of the segregating chromosomes. The interkinetic envelope shares common features with the nuclear envelope but also exhibits specific characteristics that distinguish it, including its lack of continuity with the endoplasmic reticulum, unique protein composition, assembly mechanism, and function in chromosome segregation. These distinct attributes collectively define the interkinetic envelope as a unique and specialized structure that has been previously overlooked.

Insights into targeting LKB1 in tumorigenesis

Genetic alterations to serine-threonine kinase 11 (STK11) have been implicated in Peutz-Jeghers syndrome and tumorigenesis. Further exploration of the context-specific roles of liver kinase B1 (LKB1; encoded by STK11) observed that it regulates AMP-activated protein kinase (AMPK) and AMPK-related kinases. Given that both migration and proliferation are enhanced with the loss of LKB1 activity combined with the prevalence of STK11 genetic alterations in cancer biopsies, LKB1 was marked as a tumor suppressor. However, the role of LKB1 in tumorigenesis is paradoxical as LKB1 activates autophagy and reactive oxygen species scavenging while dampening anoikis, which contribute to cancer cell survival. Due to the pro-tumorigenic properties of LKB1, targeting LKB1 pathways is now relevant for cancer treatment. With the recent successes of targeting LKB1 signaling in research and clinical settings, and enhanced cytotoxicity of chemical compounds in LKB1-deficient tumors, there is now a need for LKB1 inhibitors. However, validating LKB1 inhibitors is challenging as LKB1 adaptor proteins, nucleocytoplasmic shuttling, and splice variants all manipulate LKB1 activity. Furthermore, STE-20-related kinase adaptor protein (STRAD) and mouse protein 25 dictate LKB1 cellular localization and kinase activity. For these reasons, prior to assessing the efficacy and potency of pharmacological candidates, the functional status of LKB1 needs to be defined. Therefore, to improve the understanding of LKB1 in physiology and oncology, this review highlights the role of LKB1 in tumorigenesis and addresses the therapeutic relevancy of LKB1 inhibitors.

Direct extrusion of multifascicle prevascularized human skeletal muscle for volumetric muscle loss surgery

Skeletal muscle is composed of multiple fascicles, which are parallel bundles of muscle fibers surrounded by connective tissues that contain blood vessels and nerves. Here, we fabricated multifascicle human skeletal muscle scaffolds that mimic the natural structure of human skeletal muscle bundles using a seven-barrel nozzle. For the core material to form the fascicle structure, human skeletal myoblasts were encapsulated in Matrigel with calcium chloride. Meanwhile, the shell that plays a role as the connective tissue, human fibroblasts and human umbilical vein endothelial cells within a mixture of porcine muscle decellularized extracellular matrix and sodium alginate at a 95:5 ratio was used. We assessed four types of extruded scaffolds monolithic-monoculture (Mo-M), monolithic-coculture (Mo-C), multifascicle-monoculture (Mu-M), and multifascicle-coculture (Mu-C) to determine the structural effect of muscle mimicking scaffold. The Mu-C scaffold outperformed other scaffolds in cell proliferation, differentiation, vascularization, mechanical properties, and functionality. In an in vivo mouse model of volumetric muscle loss, the Mu-C scaffold effectively regenerated the tibialis anterior muscle defect, demonstrating its potential for volumetric muscle transplantation. Our nozzle will be further used to produce other volumetric functional tissues, such as tendons and peripheral nerves.

Concatemer-assisted stoichiometry analysis: targeted mass spectrometry for protein quantification

Large multiprotein machines are central to many biological processes. However, stoichiometric determination of protein complex subunits in their native states presents a significant challenge. This study addresses the limitations of current tools in accuracy and precision by introducing concatemer-assisted stoichiometry analysis (CASA). CASA leverages stable isotope-labeled concatemers and liquid chromatography-parallel reaction monitoring-mass spectrometry (LC-PRM-MS) to achieve robust quantification of proteins with sub-femtomole sensitivity. As a proof of concept, CASA was applied to study budding yeast kinetochores. Stoichiometries were determined for ex vivo reconstituted kinetochore components, including the canonical H3 nucleosomes, centromeric (Cse4CENP-A) nucleosomes, centromere proximal factors (Cbf1 and CBF3 complex), inner kinetochore proteins (Mif2CENP-C, Ctf19CCAN complex), and outer kinetochore proteins (KMN network). Absolute quantification by CASA revealed Cse4CENP-A as a cell cycle-controlled limiting factor for kinetochore assembly. These findings demonstrate that CASA is applicable for stoichiometry analysis of multiprotein assemblies.

The use of a multi-metric readout screen to identify EHMT2/G9a-inhibition as a modulator of cancer-associated fibroblast activation state

Cancer-associated fibroblasts (CAFs) play a pivotal role in cancer progression, including mediating tumour cell invasion via their pro-invasive secretory profile and ability to remodel the extracellular matrix (ECM). Given that reduced CAF abundance in tumours correlates with improved outcomes in various cancers, we set out to identify epigenetic targets involved in CAF activation in regions of tumour-stromal mixing with the goal of reducing tumour aggressiveness. Using the GLAnCE (Gels for Live Analysis of Compartmentalized Environments) platform, we performed an image-based, phenotypic screen that enabled us to identify modulators of CAF abundance and the capacity of CAFs to induce tumour cell invasion. We identified EHMT2 (also known as G9a), an enzyme that targets the methylation of histone 3 lysine 9 (H3K9), as a potent modulator of CAF abundance and CAF-mediated tumour cell invasion. Transcriptomic and functional analysis of EHMT2-inhibited CAFs revealed EHMT2 participated in driving CAFs towards a pro-invasive phenotype and mediated CAF hyperproliferation, a feature typically associated with activated fibroblasts in tumours. Our study suggests that EHMT2 regulates CAF state within the tumour microenvironment by impacting CAF activation, as well as by magnifying the pro-invasive effects of these activated CAFs on tumour cell invasion through promoting CAF hyperproliferation.

Crosstalk between degradation and bioenergetics: how autophagy and endolysosomal processes regulate energy production

Cells undergo metabolic reprogramming to adapt to changes in nutrient availability, cellular activity, and transitions in cell states. The balance between glycolysis and mitochondrial respiration is crucial for energy production, and metabolic reprogramming stipulates a shift in such balance to optimize both bioenergetic efficiency and anabolic requirements. Failure in switching bioenergetic dependence can lead to maladaptation and pathogenesis. While cellular degradation is known to recycle precursor molecules for anabolism, its potential role in regulating energy production remains less explored. The bioenergetic switch between glycolysis and mitochondrial respiration involves transcription factors and organelle homeostasis, which are both regulated by the cellular degradation pathways. A growing body of studies has demonstrated that both stem cells and differentiated cells exhibit bioenergetic switch upon perturbations of autophagic activity or endolysosomal processes. Here, we highlighted the current understanding of the interplay between degradation processes, specifically autophagy and endolysosomes, transcription factors, endolysosomal signaling, and mitochondrial homeostasis in shaping cellular bioenergetics. This review aims to summarize the relationship between degradation processes and bioenergetics, providing a foundation for future research to unveil deeper mechanistic insights into bioenergetic regulation.

Effects of environmentally relevant concentrations of glyphosate and aminomethylphosphonic acid on biotransformation and stress response proteins in the liver of zebrafish (Danio rerio)

Herbicides pose a threat to various non-target organisms, including fish. A widely used herbicide, glyphosate, and its main breakdown product, aminomethylphosphonic acid (AMPA), are quite ubiquitous in freshwater systems. The aim of this work was to analyze changes in the relative abundance of hepatic proteins participating in the biotransformation and response to chemical stress in adult zebrafish Danio rerio exposed to environmentally relevant concentrations of glyphosate (100 μg/L), AMPA (100 μg/L), and their mixture (50 μg/L + 50 μg/L) for two weeks. Proteomic analysis showed that the tested concentrations caused dysregulation of various biotransformation proteins, the most upregulated of which in all treatment groups was the Phase I enzyme cyp27a7. While glyphosate had a more pronounced impact on the biotransformation pathways, AMPA showed stronger interference with redox homeostasis. When acting together, the parent compound and its metabolite were more potent to disturb fish metabolic processes, including nucleotide metabolism and proteasome pathway, and to downregulate proteins known for their roles in protection from oxidative modifications of cellular constituents and disruption of redox signaling.

Spastin and alsin protein interactome analyses begin to reveal key canonical pathways and suggest novel druggable targets

Developing effective and long-term treatment strategies for rare and complex neurodegenerative diseases is challenging. One of the major roadblocks is the extensive heterogeneity among patients. This hinders understanding the underlying disease-causing mechanisms and building solutions that have implications for a broad spectrum of patients. One potential solution is to develop personalized medicine approaches based on strategies that target the most prevalent cellular events that are perturbed in patients. Especially in patients with a known genetic mutation, it may be possible to understand how these mutations contribute to problems that lead to neurodegeneration. Protein-protein interaction analyses offer great advantages for revealing how proteins interact, which cellular events are primarily involved in these interactions, and how they become affected when key genes are mutated in patients. This line of investigation also suggests novel druggable targets for patients with different mutations. Here, we focus on alsin and spastin, two proteins that are identified as "causative" for amyotrophic lateral sclerosis and hereditary spastic paraplegia, respectively, when mutated. Our review analyzes the protein interactome for alsin and spastin, the canonical pathways that are primarily important for each protein domain, as well as compounds that are either Food and Drug Administration-approved or are in active clinical trials concerning the affected cellular pathways. This line of research begins to pave the way for personalized medicine approaches that are desperately needed for rare neurodegenerative diseases that are complex and heterogeneous.

Neutrophils exhibit flexible migration strategies and trail formation mechanisms on varying adhesive substrates

Substrate anchorage is essential for cell migration, and actin polymerization at cell front and myosin contractility at cell rear are known to govern cell forward movement. Yet their differential driving strategies for neutrophil migration on distinct adhesiveness substrates and their contributions to the migration-induced trail formation remain unclear. Here we explore the morphological changes, migration dynamics, and trail formation of neutrophils on ICAM-1 and PLL substrates, with a focus on the relationships among adhesive forces, traction forces, and out-of-plane forces. Results indicate that, on ICAM-1, neutrophil migration and trail formation rely on the coordinated interactions of Arp2/3 and myosin, along with biochemical regulation (via Syk and calpain) of adhesion and de-adhesion. This pattern leads to traction forces being concentrated at relatively fewer adhesive sites, facilitating cell forward migration. On PLL, however, neutrophils primarily depend on Arp2/3-mediated actin polymerization, resulting in a broader distribution of traction forces and weaker adhesions, which allows for higher leading-edge migrating velocities. Elevated membrane tension and out-of-plane forces generated by bleb protrusions on PLL reduce the reliance on myosin-driven contraction at the trailing edge, enabling easier tail detachment through elastic recoil. This work highlights the differential impact of substrate adhesiveness on neutrophil migration and trail formation and dynamics, providing new insights into cell migration mechanisms and potential therapeutic targets for inflammatory and immune-related disorders.

Electrically-stimulated cellular and tissue events are coordinated through ion channel-mediated calcium influx and chromatin modifications across the cytosol-nucleus space

Electrical stimulation (ES) through biomaterials and devices has been implicated in activating diverse cell behaviors while facilitating tissue healing process. Despite its significance in modulating biological events, the mechanisms governing ES-activated cellular phenomena remain largely elusive. Here, we demonstrated that millisecond-pulsed temporal ES profoundly impacted a spectrum of cellular events across the membrane-cytosol-nuclear space. These include activated ion channels, intracellular calcium influx, actomyosin contractility, cell migration and proliferation, and secretome release. Such events were coordinated mainly through ES-activated ion channels and calcium oscillation dynamics. Notably, ES increased the chromatin accessibility of genes, particularly those associated with the ES-activated cellular events, underscoring the significance of epigenetic changes in ES-induced behavioral outcomes. We identified histone acetylation (mediated by histone acetyltransferases), among other chromatin modifications, is key in reshaping the chromatin landscape upon ES. These observations were further validated through experiments involving ex vivo skin tissue samples, including activated ion channels and calcium influx, increased cell proliferation and actomyosin contractility, elevated secretome profile, and more accessible chromatin structure following ES. This work provides novel insights into the mechanisms underlying ES-activated cell and tissue events, ultimately guiding design principles for the development of electrical devices and materials effective for tissue repair and wound healing.

Nitric oxide-based treatments improve wound healing associated with diabetes mellitus

Non-healing wounds are long-term complications of diabetes mellitus (DM) that increase mortality risk and amputation-related disability and decrease the quality of life. Nitric oxide (NO·)-based treatments (i.e., use of both systemic and topical NO· donors, NO· precursors, and NO· inducers) have received more attention as complementary approaches in treatments of DM wounds. Here, we aimed to highlight the potential benefits of NO·-based treatments on DM wounds through a literature review of experimental and clinical evidence. Various topical NO·-based treatments have been used. In rodents, topical NO·-based therapy facilitates wound healing, manifested as an increased healing rate and a decreased half-closure time. The wound healing effect of NO·-based treatments is attributed to increasing local blood flow, angiogenesis induction, collagen synthesis and deposition, re-epithelization, anti-inflammatory and anti-oxidative properties, and potent broad-spectrum antibacterial effects. The existing literature lacks human clinical evidence on the safety and efficacy of NO·-based treatments for DM wounds. Translating experimental favors of NO·-based treatments of DM wounds into human clinical practice needs conducting clinical trials with well-predefined effect sizes, i.e., wound reduction area, rate of wound healing, and hospital length of stay.

New idea of Fuke Qianjin capsule in treating sequelae of pelvic inflammatory disease: Anti-inflammatory in the early stage and reparative in the later stage

ETHNOPHARMACOLOGICAL RELEVANCE

Sequelae of pelvic inflammatory disease (SPID) occurs in female internal genitalia and surrounding connective tissue. Recent clinical studies have shown that the traditional Chinese medicine Fuke Qianjin capsule (FKQ) can shorten the course of this disease, but its pharmacological effects and potential mechanism have not been fully elucidated.

AIM OF THE STUDY

This study aimed to investigate the efficacy and underlying mechanisms of FKQ in the treatment of SPID.

METHODS

In this study, we first established a mixed infection model to explore the protective effect of FKQ on common pathogens of SPID. Afterwards, mixed bacterial infection and mechanical injury were used in a SPID rat model to explore the protective mechanism of FKQ on SPID rats. Inflammation, repair and immune cells were tested.

RESULTS

FKQ has a protective effect against infections caused by SPID pathogenic bacterial and may reduce mortality from mixed infections. In the SPID model, FKQ improved pathological damage to the uterus, reduced the area of uterine fibrosis, and inhibited the levels of cytokines (TNF-α, IL-6, IL-1β, IL-18, TGF-β1 and VEGF) caused by pathogenic bacteria. Moreover, FKQ treatment reduced the accumulation of NLRP3, Caspase-1, GSDMD Vimentin, and Cytokeratin 18 in the uterus and suppressed the expression of TGF-β1 and VEGF in the fallopian tubes, thereby reducing inflammation and promoting mucosal repair. In addition, FKQ can restore the immune function balance of SPID rats by increasing the proportion of Treg cells in the spleen and thymus in a rat model of SPID, reducing the proportion of Th17 lymphocytes, and promoting an immunological balance of Treg/Th17 cells, thereby regulating the immune system of the body.

CONCLUSION

In summary, FKQ treatment for SPID is the result of a fourfold combination of antibacterial, anti-inflammatory, reparative and immune-enhancing activities.

MCM10: A potential biomarker for cervical cancer and precancerous lesions

Cervical cancer remains a significant health burden worldwide, emphasizing the need for early detection and intervention. DNA replication is perturbed in cancer cells, and the minichromosome maintenance protein 10 plays an important role in origin firing. By analyzing the MCM10 mRNA expression in healthy controls, precancerous lesions, and cervical cancer using qRT-PCR, we can infer if it can be considered a biomarker. We collected cervical smear samples from patients and performed MCM10 expression analysis to set up thresholds for risk stratification. We also investigated the HPV status among the patient samples with precancerous lesions and cervical cancer and found 70 % of them to be positive. Our results demonstrated a significant upregulation of MCM10 mRNA expression in tumor samples (n = 40, 7.83 ± 1.2) and precancerous lesions (n = 54, 5.69 ± 1.4) compared to normal (n = 50, 4.27 ± 0.80) with a R2 value of 0.59, confirming its role in the progression and development of cervical cancer. In conclusion, this study emphasizes the potential role of MCM10 as a biomarker. Our study would improve early detection rates, and we propose MCM10-based community screening for risk stratification, prevention, and prognosis.

Proteomic evidence for seed odor modifying olfaction and spatial memory in a scatter-hoarding animal

Seed odor plays a crucial role in affecting the scatter-hoarding behavior of small rodents that rely on spatial memory and olfaction to cache and recover. However, evidence of how seed odor modifies olfaction function and spatial memory is still lacking. Here, we coated seeds with waterproof glue to test how seed odor intensity alters the proteome of both the olfactory bulbs and hippocampus of a dominant scatter-hoarding rodent, Leopoldamys edwardsi, in Southwest China. We showed that animals repeatedly caching and recovering weak odor seeds exhibited greater olfactory ability and spatial memory, as indicated by alterations in the protein profiles of the olfactory bulbs and hippocampus. The upregulation of proteins closely related to neural connections between the olfactory bulb and hippocampus is highly responsible for improved olfactory function and spatial memory. Our study provides new insights into how scatter-hoarding rodents manage and respond to cached seeds differing in odor intensity from a neurobiological perspective, which is of significant importance for better understanding the parallel evolution of the olfactory and hippocampal systems.

A proteome-wide yeast degron collection for the dynamic study of protein function

Genome-wide collections of yeast strains, known as libraries, revolutionized the way systematic studies are carried out. Specifically, libraries that involve a cellular perturbation, such as the deletion collection, have facilitated key biological discoveries. However, short-term rewiring and long-term accumulation of suppressor mutations often obscure the functional consequences of such perturbations. We present the AID library which supplies "on demand" protein depletion to overcome these limitations. Here, each protein is tagged with a green fluorescent protein (GFP) and an auxin-inducible degron (AID), enabling rapid protein depletion that can be quantified systematically using the GFP element. We characterized the degradation response of all strains and demonstrated its utility by revisiting seminal yeast screens for genes involved in cell cycle progression as well as mitochondrial distribution and morphology. In addition to recapitulating known phenotypes, we also uncovered proteins with previously unrecognized roles in these central processes. Hence, our tool expands our knowledge of cellular biology and physiology by enabling access to phenotypes that are central to cellular physiology and therefore rapidly equilibrated.

Functional genetics reveals modulators of antimicrotubule drug sensitivity

Microtubules play essential roles in diverse cellular processes and are important pharmacological targets for treating human disease. Here, we sought to identify cellular factors that modulate the sensitivity of cells to antimicrotubule drugs. We conducted a genome-wide CRISPR/Cas9-based functional genetics screen in human cells treated with the microtubule-destabilizing drug nocodazole or the microtubule-stabilizing drug paclitaxel. We further conducted a focused secondary screen to test drug sensitivity for ∼1,400 gene targets across two distinct human cell lines and to additionally test sensitivity to the KIF11 inhibitor, STLC. These screens defined gene targets whose loss enhances or suppresses sensitivity to antimicrotubule drugs. In addition to gene targets whose loss sensitized cells to multiple compounds, we observed cases of differential sensitivity to specific compounds and differing requirements between cell lines. Our downstream molecular analysis further revealed additional roles for established microtubule-associated proteins and identified new players in microtubule function.

The kinetochore protein KNL-1 regulates the actin cytoskeleton to control dendrite branching

The function of the nervous system is intimately tied to its complex and highly interconnected architecture. Precise control of dendritic branching in individual neurons is central to building the complex structure of the nervous system. Here, we show that the kinetochore protein KNL-1 and its associated KMN (Knl1/Mis12/Ndc80 complex) network partners, typically known for their role in chromosome-microtubule coupling during mitosis, control dendrite branching in the Caenorhabditis elegans mechanosensory PVD neuron. KNL-1 restrains excess dendritic branching and promotes contact-dependent repulsion events, ensuring robust sensory behavior and preventing premature neurodegeneration. Unexpectedly, KNL-1 loss resulted in significant alterations of the actin cytoskeleton alongside changes in microtubule dynamics within dendrites. We show that KNL-1 modulates F-actin dynamics to generate proper dendrite architecture and that its N-terminus can initiate F-actin assembly. These findings reveal that the postmitotic neuronal KMN network acts to shape the developing nervous system by regulating the actin cytoskeleton and provide new insight into the mechanisms controlling dendrite architecture.

Synaptic sabotage: How Tau and α-Synuclein undermine synaptic health

Synaptic dysfunction is one of the earliest cellular defects observed in Alzheimer's disease (AD) and Parkinson's disease (PD), occurring before widespread protein aggregation, neuronal loss, and cognitive decline. While the field has focused on the aggregation of Tau and α-Synuclein (α-Syn), emerging evidence suggests that these proteins may drive presynaptic pathology even before their aggregation. Therefore, understanding the mechanisms by which Tau and α-Syn affect presynaptic terminals offers an opportunity for developing innovative therapeutics aimed at preserving synapses and potentially halting neurodegeneration. This review focuses on the molecular defects that converge on presynaptic dysfunction caused by Tau and α-Syn. Both proteins have physiological roles in synapses. However, during disease, they acquire abnormal functions due to aberrant interactions and mislocalization. We provide an overview of current research on different essential presynaptic pathways influenced by Tau and α-Syn. Finally, we highlight promising therapeutic targets aimed at maintaining synaptic function in both tauopathies and synucleinopathies.

One step 4× and 12× 3D-ExM enables robust super-resolution microscopy of nanoscale cellular structures

Super-resolution microscopy has become an indispensable tool across diverse research fields, offering unprecedented insights into biological architectures with nanometer scale resolution. Compared with traditional nanometer-scale imaging methods such as electron microscopy, super-resolution microscopy offers several advantages, including the simultaneous labeling of multiple target biomolecules with high specificity and simpler sample preparation, making it accessible to most researchers. In this study, we introduce two optimized methods of super-resolution imaging: 4-fold and 12-fold 3D-isotropic and preserved Expansion Microscopy (4× and 12× 3D-ExM). 3D-ExM is a straightforward expansion microscopy technique featuring a single-step process, providing robust and reproducible 3D isotropic expansion for both 2D and 3D cell culture models. With standard confocal microscopy, 12× 3D-ExM achieves a lateral resolution of <30 nm, enabling the visualization of nanoscale structures, including chromosomes, kinetochores, nuclear pore complexes, and Epstein-Barr virus particles. These results demonstrate that 3D-ExM provides cost-effective and user-friendly super-resolution microscopy, making it highly suitable for a wide range of cell biology research, including studies on cellular and chromatin architectures.

Securin regulates the spatiotemporal dynamics of separase

Separase regulates multiple aspects of the metaphase-to-anaphase transition. Separase cleaves cohesin to allow chromosome segregation and localizes to vesicles to promote exocytosis. The anaphase-promoting complex/cyclosome (APC/C) activates separase by ubiquitinating its inhibitory chaperone, securin, triggering its degradation. How this pathway controls the exocytic function of separase is unknown. During meiosis I, securin is degraded over several minutes, while separase rapidly relocalizes from kinetochore structures at the spindle and cortex to sites of action on chromosomes and vesicles at anaphase onset. The loss of cohesin coincides with the relocalization of separase to the chromosome midbivalent at anaphase onset. APC/C depletion prevents separase relocalization, while securin depletion causes precocious separase relocalization. Expression of non-degradable securin inhibits chromosome segregation, exocytosis, and separase localization to vesicles but not to the anaphase spindle. We conclude that APC/C-mediated securin degradation controls separase localization. This spatiotemporal regulation will impact the effective local concentration of separase for more precise targeting of substrates in anaphase.

Non-canonical CDK6 activity promotes cilia disassembly by suppressing axoneme polyglutamylation

Tubulin polyglutamylation is a posttranslational modification that occurs primarily along the axoneme of cilia. Defective axoneme polyglutamylation impairs cilia function and has been correlated with ciliopathies, including Joubert Syndrome (JBTS). However, the precise mechanisms regulating proper axoneme polyglutamylation remain vague. Here, we show that cyclin-dependent kinase 6 (CDK6), but not its paralog CDK4, localizes to the cilia base and suppresses axoneme polyglutamylation by phosphorylating RAB11 family interacting protein 5 (FIP5) at site S641, a critical regulator of cilia import of glutamylases. S641 phosphorylation disrupts the ciliary recruitment of FIP5 and its association with RAB11, thereby reducing the ciliary import of glutamylases. Encouragingly, the FDA-approved CDK4/6 inhibitor Abemaciclib can effectively restore cilia function in JBTS cells with defective glutamylation. In summary, our study elucidates the regulatory mechanisms governing axoneme polyglutamylation and suggests that developing CDK6-specific inhibitors could be a promising therapeutic strategy to enhance cilia function in ciliopathy patients.

Neuronal constitutive endolysosomal perforations enable α-synuclein aggregation by internalized PFFs

Endocytosis, required for the uptake of receptors and their ligands, can also introduce pathological aggregates such as α-synuclein (α-syn) in Parkinson's Disease. We show here the unexpected presence of intrinsically perforated endolysosomes in neurons, suggesting involvement in the genesis of toxic α-syn aggregates induced by internalized preformed fibrils (PFFs). Aggregation of endogenous α-syn in late endosomes and lysosomes of human iPSC-derived neurons (iNs), seeded by internalized α-syn PFFs, caused the death of the iNs but not of the parental iPSCs and non-neuronal cells. Live-cell imaging of iNs showed constitutive perforations in ∼5% of their endolysosomes. These perforations, identified by 3D electron microscopy in iNs and CA1 pyramidal neurons and absent in non-neuronal cells, may facilitate cytosolic access of endogenous α-syn to PFFs in the lumen of endolysosomes, triggering aggregation. Inhibiting the PIKfyve phosphoinositol kinase reduced α-syn aggregation and associated iN death, even with ongoing PFF endolysosomal entry, suggesting that maintaining endolysosomal integrity might afford a therapeutic strategy to counteract synucleinopathies.

Identification of coilin interactors reveals coordinated control of Cajal body number and structure

The cell nucleus contains distinct biomolecular condensates that form at specific genetic loci, organize chromosomes in 3D space, and regulate RNA processing. Among these, Cajal bodies (CBs) require key "scaffolding" proteins for their assembly, which is not fully understood. Here, we employ proximity biotinylation, mass spectrometry, and functional screening to comprehensively identify and test the functions of CB components. We document 144 protein interactors of coilin, of which 70 were newly detected, and establish 25 players needed for CB assembly and/or maintenance. Surprisingly, the depletion of nine coilin interactors-mostly constituents of the 60S ribosome (RPLs)-increased CB number and caused subdomains defined by coilin and the survival motor neuron protein (SMN) to merge. These phenotypes were traceable to altered nuclear levels of dimethylarginine. Our data implicate RPL24 and other players in the regulation of CBs by modulating posttranslational modifications. Moreover, the prevalence of transcription factors among the identified components highlights roles for gene activity in CB assembly and nuclear positioning.

SIRT1 regulates cigarette smoke extract‑induced alveolar macrophage polarization and inflammation by inhibiting the TRAF6/NLRP3 signaling pathway

M1 macrophages activated by cigarette smoke extract (CSE) serve a pro‑inflammatory role in chronic obstructive pulmonary disease (COPD). The expression of silent information regulator 1 (SIRT1) is decreased in the alveolar macrophages of patients with COPD. However, whether SIRT1 is involved in COPD by regulating macrophage polarization remains unknown. Rat Alveolar Macrophage NR8383 cells were exposed to CSE. Cell Counting Kit‑8 assay, western blot assay and ELISA showed that with increasing concentration of CSE, the activity of NR8383 cells and expression of SIRT1 gradually decreased, while the release of inflammatory cytokines TNFα, IL‑1β and IL‑6 increased. As shown in western blot or Immunofluorescence assays, exposure to CSE also increased expression levels of the M1 markers inducible nitric oxide synthase and CD86, whereas it downregulated expression of the M2 markers arginase 1 and CD206. In addition, CSE increased expression of TNF receptor associated factor 6 (TRAF6), NOD‑like receptor thermal protein domain associated protein 3 (NLRP3) and cleaved caspase‑1 protein in NR8383 cells. Overexpression plasmids of SIRT1 and TRAF6 significantly reversed the aforementioned changes induced by CSE. Moreover, immunoprecipitation demonstrated that TRAF6 could bind to NLRP3. The overexpression of TRAF6 notably attenuated the regulatory effects of overexpression of SIRT1 on polarization and inflammation in NR8383 cells. Conversely, overexpression of SIRT1 inhibited the TRAF6/NLRP3 signaling pathway, thereby suppressing CSE‑induced M1 polarization and release of inflammatory factors in NR8383 cells. The present study demonstrates that SIRT1 regulates CSE‑induced alveolar macrophage polarization and inflammation by inhibiting the TRAF6/NLRP3 signaling pathway.

Microtubule actin crosslinking factor 1, a brain tumor oncoprotein (Review)

Microtubule actin crosslinking factor 1 (MACF1), is a cytoskeletal protein that functions as a crosslinker between microtubules and actin filaments, with early studies expanding the role of this spectraplakin protein to the central nervous system and Wnt signaling. In the early 2000's, genetic alterations of MACF1 were identified in several cancers suggesting that this cytoskeletal crosslinker was involved in tumor development and progression, while preclinical studies provided evidence that MACF1 is a potential diagnostic and prognostic biomarker and therapeutic target in glioblastomas, a central nervous system cancer derived from astrocytes and neural progenitor stem cells. Furthermore, investigations in glioblastomas demonstrated that genetic inhibitory targeting of this spectraplakin protein alone and in combination with DNA damaging agents had synergistic antitumorigenic effects. The established role of MACF1 in Wnt signaling, a known mechanistic driver of central nervous system development and pro-tumorigenic cell behavior in glioblastomas, provide a premise for addressing the potential of this spectraplakin protein as a novel oncoprotein in cancers with origins in the nervous system. The present review provides a summary of the role and function of MACF1 in the central nervous system, Wnt signaling and cancer development, specifically as an oncoprotein that underlie the transformation and oncogenic properties of glioblastomas.

Liquid-liquid phase separation in viral infection: From the occurrence and function to treatment potentials

Liquid-liquid phase separation (LLPS) of biomacromolecules, as a widespread cellular functional mechanism, is closely related to life processes, and is also commonly present in the lifecycle of viruses. Viral infection often leads to the recombination and redistribution of intracellular components to form biomacromolecule condensates assembled from viral replication-related proteins and intracellular components, which plays an important role in the process of viral infection. In this review, the key and influencing factors of LLPS are generalized, which mainly depend on various molecular interactions and environmental conditions in solution. Meanwhile, some examples of viruses utilizing LLPS are summarized, which are conducive to further understanding the subtle and complex biological regulatory processes between phase condensation and viruses. Finally, some representative antiviral drugs targeting phase separation that have been discovered are also outlined. In conclusion, in-depth study of the role of LLPS in viral infection is helpful to understand the mechanisms of virus-related diseases from a new perspective, and also provide a new therapeutic strategy for future treatments.

Vinculin-Arp2/3 interaction inhibits branched actin assembly to control migration and proliferation

Vinculin is a mechanotransducer that reinforces links between cell adhesions and linear arrays of actin filaments upon myosin-mediated contractility. Both adhesions to the substratum and neighboring cells, however, are initiated within membrane protrusions that originate from Arp2/3-nucleated branched actin networks. Vinculin has been reported to interact with the Arp2/3 complex, but the role of this interaction remains poorly understood. Here, we compared the phenotypes of vinculin knock-out (KO) cells with those of knock-in (KI-P878A) cells, where the point mutation P878A that impairs the Arp2/3 interaction is introduced in the two vinculin alleles of MCF10A mammary epithelial cells. The interaction of vinculin with Arp2/3 inhibits actin polymerization at membrane protrusions and decreases migration persistence of single cells. In cell monolayers, vinculin recruits Arp2/3 and the vinculin-Arp2/3 interaction participates in cell-cell junction plasticity. Through this interaction, vinculin controls the decision to enter a new cell cycle as a function of cell density.

RhoA regulates oligodendrocyte differentiation and myelination by orchestrating cortical and membrane tension

Timely differentiation and myelin formation by oligodendrocytes are essential for the physiological functioning of the central nervous system (CNS). While the Rho GTPase RhoA has been hinted as a negative regulator of myelin sheath formation, the precise in vivo mechanisms have remained elusive. Here we show that RhoA controls the timing and progression of myelination by oligodendrocytes through a fine-tuned balance between cortical tension, membrane tension and cell shape. Using a conditional mouse model, we observe that Rhoa ablation results in the acceleration of myelination driven by hastened differentiation and facilitated through membrane expansion induced by changes in MLCII activity and in F-actin redistribution and turnover within the cell. These findings reveal RhoA as a central molecular integrator of alterations in actin cytoskeleton, actomyosin contractility and membrane tension underlying precise morphogenesis of oligodendrocytes and normal myelination of the CNS.

Ca2+/calmodulin signaling in organismal aging and cellular senescence: Impact on human diseases

Molecular mechanisms of aging processes at the level of organisms and cells are in the focus of a large number of research laboratories. This research culminated in recent breakthroughs, which contributed to the better understanding of the natural aging process and aging associated malfunctions leading to age-related diseases. Ca2+ in connection with its master intracellular sensor protein calmodulin (CaM) regulates a plethora of crucial cellular processes orchestrating a wide range of signaling processes. This review focuses on the involvement of Ca2+/CaM in cellular mechanisms, which are associated with normal aging, as well as playing a role in the development of diseases connected with signaling processes during aging. We specifically highlight processes that involve inactivation of proteins, which take part in Ca2+/CaM regulatory systems by oxygen or nitrogen free radical species, during organismal aging and cellular senescence. As examples of organs where aging processes have recently been investigated, we chose to review the literature on molecular aging processes with involvement of Ca2+/CaM in heart and neuronal diseases, as well as in cancer and metabolic diseases, all deeply affected by aging. In addition, this article focuses on cellular senescence, a mechanism that may contribute to aging processes and therefore has been proposed as a target to interfere with the progression of age-associated diseases.

RuvBL1/2 reduce toxic dipeptide repeat protein burden in multiple models of C9orf72-ALS/FTD

A G4C2 hexanucleotide repeat expansion in C9orf72 is the most common cause of amyotrophic lateral sclerosis and frontotemporal dementia (C9ALS/FTD). Bidirectional transcription and subsequent repeat-associated non-AUG (RAN) translation of sense and antisense transcripts leads to the formation of five dipeptide repeat (DPR) proteins. These DPRs are toxic in a wide range of cell and animal models. Therefore, decreasing RAN-DPRs may be of therapeutic benefit in the context of C9ALS/FTD. In this study, we found that C9ALS/FTD patients have reduced expression of the AAA+ family members RuvBL1 and RuvBL2, which have both been implicated in aggregate clearance. We report that overexpression of RuvBL1, but to a greater extent RuvBL2, reduced C9orf72-associated DPRs in a range of in vitro systems including cell lines, primary neurons from the C9-500 transgenic mouse model, and patient-derived iPSC motor neurons. In vivo, we further demonstrated that RuvBL2 overexpression and consequent DPR reduction in our Drosophila model was sufficient to rescue a number of DPR-related motor phenotypes. Thus, modulating RuvBL levels to reduce DPRs may be of therapeutic potential in C9ALS/FTD.

PI3K/Akt inhibition promotes AR activity and prostate cancer cell proliferation through p35-CDK5 modulation

Aberrant PI3K/Akt activation is linked to prostate cancer (PCa) malignancy, while androgen receptor (AR) is critical in early-stage PCa development. Investigating the interaction between these pathways is crucial for PCa malignancy. Our previous study demonstrated that p35-CDK5 mediates post-translational modifications of AR, STAT3, and p21CIP1, eventually promoting PCa cell growth. This study revealed the role of p35-CDK5 in between PI3K/Akt and AR by utilizing LNCaP and 22Rv1 cells. Through the TCGA database analysis, we observed a positive correlation between PTEN and p35 expression, implying a potential negative correlation between PI3K/Akt activation and p35-CDK5. Inhibiting PI3K/Akt with LY294002, Capivasertib (AZD5363), or using an inactive Akt mutant significantly increased p35 expression and subsequently enhanced AR stability and activation in PCa cells. On the other hand, CDK5-knockdown reversed these effects. The involvement of the β-catenin/Egr1-axis was observed in regulating PI3K/Akt inhibition and p35-CDK5 activation, implying a possible mechanistic connection. Importantly, CDK5 knockdown further reduced PI3K/Akt-inhibition-induced AR and cell viability maintenance, suggesting a compensatory role for CDK5-AR in maintaining cell viability under Akt inhibition. In conclusion, PI3K/Akt inhibition could trigger p35-CDK5-dependent AR activation and cell viability, highlighting p35-CDK5 as a critical link connecting PI3K/Akt inhibition to AR activation and pivotal in PCa cell resistance to PI3K/Akt blockade.

ciBAR1 loss in mice causes laterality defects, pancreatic degeneration, and altered glucose tolerance

Bin/Amphiphysin/Rvs (BAR) domains are highly conserved domains found in all eukaryotes. BAR domain proteins form crescent-shaped dimers that sense and sculpt curved lipid membranes and play key roles in various cellular processes. However, their functions in mammalian development are poorly understood. We previously demonstrated that Chibby1-interacting BAR domain-containing 1 (ciBAR1, formerly known as FAM92A) localizes to the ciliary base and plays a critical role in ciliogenesis. Here, we report ciliopathy phenotypes of ciBAR1-KO mice. We found that ∼28% of ciBAR1-KO mice show embryonic lethality because of randomized left-right asymmetry; the rest survive into adulthood with no gross morphological abnormalities. Histological assessments of ciliated tissues revealed exocrine pancreatic lesions. Although overall endocrine islet morphology appeared to be normal, ciBAR1-KO mice showed impaired glucose tolerance. Examination of ductal and islet cilia revealed that cilia number and length were significantly reduced in ciBAR1-KO pancreata. ciBAR1-KO MEFs also exhibited ciliary defects. Our findings indicate that ciBAR1 plays a critical role in ciliogenesis depending on the tissue and cell type in mice.

The enigmatic role of SIRT2 in the cardiovascular system: Deciphering its protective and detrimental actions to unlock new avenues for therapeutic intervention

Cardiovascular diseases (CVDs) are leading causes of mortality throughout the world, and hence, there is a critical need to elucidate their molecular mechanisms. The Sirtuin (SIRT) family of NAD+-dependent enzymes has recently been shown to play a critical role in cardiovascular health and disease, and several SIRT isoforms, especially SIRT1 and SIRT3, have been amply investigated. However, the precise function of SIRT2 is only partially explored. Here, we review the current understanding of the involvement of SIRT2 in various cardiovascular pathologies, such as cardiac hypertrophy, ischemia-reperfusion injury, diabetic cardiomyopathy, and vascular dysfunction, with emphasis placed on the context-dependent protective or deleterious actions of SIRT2, including its wide array of catalytic activities which span beyond deacetylation. Furthermore, the review uncovers several unresolved research gaps for SIRT2 mechanisms by which SIRT2 modulates cardiac and vascular function during development and aging, thereby paving the way for the discovery of novel therapeutic targets as well as SIRT2-targeted interventions in the prevention and treatment of various cardiovascular diseases.

APC orchestrates microtubule dynamics by acting as a positive regulator of KIF2A and a negative regulator of CLASPs

Tumor suppressor protein Adenomatous polyposis coli protein (APC) is an EB-binding and microtubule (MT) plus end-tracking protein; however, how exactly APC regulates MT dynamics remains elusive. Here, we show that in LLC-PK1 cells, APC and KIF2A, an MT depolymerase, form a complex clustering at the cell edge and destabilize MTs at the MT plus ends. Further biochemical characterization and mutational analysis reveal key residues for the APC-KIF2A interaction. In addition, APC counteracts the major MT-stabilizer CLASPs at MT plus ends and promotes directional cell migration via modulating cell adhesion force. Reconstitution experiments demonstrate that APC potentiates KIF2A-induced MT catastrophes and antagonizes the stabilizing effect of CLASP2 in vitro. In summary, APC functions as a positive regulator of MT-destabilizer and a negative regulator of MT-stabilizer to orchestrate MT dynamics.