ABSTRACT
Systemic candidiasis is a common, high-mortality, nosocomial fungal infection. Unexpectedly, it has emerged as a complication of anti-complement C5-targeted monoclonal antibody treatment, indicating a critical niche for C5 in antifungal immunity. We identified transcription of complement system genes as the top biological pathway induced in candidemic patients and as predictive of candidemia. Mechanistically, C5a-C5aR1 promoted fungal clearance and host survival in a mouse model of systemic candidiasis by stimulating phagocyte effector function and ERK- and AKT-dependent survival in infected tissues. C5ar1 ablation rewired macrophage metabolism downstream of mTOR, promoting their apoptosis and enhancing mortality through kidney injury. Besides hepatocyte-derived C5, local C5 produced intrinsically by phagocytes provided a key substrate for antifungal protection. Lower serum C5a concentrations or a C5 polymorphism that decreases leukocyte C5 expression correlated independently with poor patient outcomes. Thus, local, phagocyte-derived C5 production licenses phagocyte antimicrobial function and confers innate protection during systemic fungal infection.
Subject(s)
Antifungal Agents , Candidiasis , Animals , Mice , Complement C5/metabolism , Phagocytes/metabolismABSTRACT
Sepsis results in elevated adenosine in circulation. Extracellular adenosine triggers immunosuppressive signaling via the A2a receptor (A2aR). Sepsis survivors develop persistent immunosuppression with increased risk of recurrent infections. We utilized the cecal ligation and puncture (CLP) model of sepsis and subsequent infection to assess the role of adenosine in post-sepsis immune suppression. A2aR-deficient mice showed improved resistance to post-sepsis infections. Sepsis expanded a subset of CD39hi B cells and elevated extracellular adenosine, which was absent in mice lacking CD39-expressing B cells. Sepsis-surviving B cell-deficient mice were more resistant to secondary infections. Mechanistically, metabolic reprogramming of septic B cells increased production of ATP, which was converted into adenosine by CD39 on plasmablasts. Adenosine signaling via A2aR impaired macrophage bactericidal activity and enhanced interleukin-10 production. Septic individuals exhibited expanded CD39hi plasmablasts and adenosine accumulation. Our study reveals CD39hi plasmablasts and adenosine as important drivers of sepsis-induced immunosuppression with relevance in human disease.
Subject(s)
Adenosine/immunology , Antigens, CD/immunology , Apyrase/immunology , Immune Tolerance/immunology , Macrophages/immunology , Plasma Cells/immunology , Sepsis/immunology , Adenosine/metabolism , Animals , Antigens, CD/metabolism , Apyrase/metabolism , Cellular Reprogramming/immunology , Macrophages/metabolism , Mice , Plasma Cells/metabolism , Receptor, Adenosine A2A/immunology , Receptor, Adenosine A2A/metabolism , Sepsis/metabolismABSTRACT
The ß3-adrenergic receptor (ß3AR) is predominantly expressed in adipose tissue and urinary bladder and has emerged as an attractive drug target for the treatment of type 2 diabetes, obesity, and overactive bladder (OAB). Here, we report the cryogenic electron microscopy structure of the ß3AR-Gs signaling complex with the selective agonist mirabegron, a first-in-class drug for OAB. Comparison of this structure with the previously reported ß1AR and ß2AR structures reveals a receptor activation mechanism upon mirabegron binding to the orthosteric site. Notably, the narrower exosite in ß3AR creates a perpendicular pocket for mirabegron. Mutational analyses suggest that a combination of both the exosite shape and the amino-acid-residue substitutions defines the drug selectivity of the ßAR agonists. Our findings provide a molecular basis for ßAR subtype selectivity, allowing the design of more-selective agents with fewer adverse effects.
Subject(s)
Acetanilides/chemistry , Adrenergic beta-3 Receptor Agonists/chemistry , Receptors, Adrenergic, beta-3/chemistry , Receptors, Adrenergic, beta-3/metabolism , Thiazoles/chemistry , Acetanilides/metabolism , Adrenergic beta-3 Receptor Agonists/metabolism , Animals , Binding Sites , Cryoelectron Microscopy , Dogs , Humans , Models, Molecular , Molecular Dynamics Simulation , Receptors, Adrenergic, beta-3/genetics , Thiazoles/metabolismABSTRACT
Recent advances in cryo-electron microscopy (Cryo-EM) have revolutionized our understanding of the complement C5a/C3a receptors that are crucial in inflammation. A recent report by Yadav et al. has elucidated the activation, ligand binding, selectivity, and signaling bias of these receptors, thereby enhancing structure-guided drug discovery. This paves the way for more effective anti-inflammatory therapies that target these receptors with unprecedented precision.
Subject(s)
Anaphylatoxins , Complement C5a , Anaphylatoxins/chemistry , Anaphylatoxins/metabolism , Complement C5a/metabolism , Complement C3a/metabolism , Cryoelectron Microscopy , Receptors, Complement/metabolismABSTRACT
Steroid receptors activate gene transcription by recruiting coactivators to initiate transcription of their target genes. For most nuclear receptors, the ligand-dependent activation function domain-2 (AF-2) is a primary contributor to the nuclear receptor (NR) transcriptional activity. In contrast to other steroid receptors, such as ERα, the activation function of androgen receptor (AR) is largely dependent on its ligand-independent AF-1 located in its N-terminal domain (NTD). It remains unclear why AR utilizes a different AF domain from other receptors despite that NRs share similar domain organizations. Here, we present cryoelectron microscopy (cryo-EM) structures of DNA-bound full-length AR and its complex structure with key coactivators, SRC-3 and p300. AR dimerization follows a unique head-to-head and tail-to-tail manner. Unlike ERα, AR directly contacts a single SRC-3 and p300. The AR NTD is the primary site for coactivator recruitment. The structures provide a basis for understanding assembly of the AR:coactivator complex and its domain contributions for coactivator assembly and transcriptional regulation.
Subject(s)
DNA/chemistry , E1A-Associated p300 Protein/metabolism , Nuclear Receptor Coactivator 3/metabolism , Receptors, Androgen/metabolism , Cryoelectron Microscopy , DNA/metabolism , E1A-Associated p300 Protein/chemistry , HEK293 Cells , Humans , Nuclear Receptor Coactivator 3/chemistry , Nucleic Acid Conformation , Protein Conformation , Receptors, Androgen/chemistry , Receptors, Androgen/genetics , Recombinant Proteins/chemistry , Recombinant Proteins/metabolismABSTRACT
Androgen receptor (AR) is a main driver for castration-resistant prostate cancer (CRPC). c-Myc is an oncogene underlying prostate tumorigenesis. Here, we find that the deubiquitinase USP11 targets both AR and c-Myc in prostate cancer (PCa). USP11 expression was up-regulated in metastatic PCa and CRPC. USP11 knockdown (KD) significantly inhibited PCa cell growth. Our RNA-seq studies revealed AR and c-Myc as the top transcription factors altered after USP11 KD. ChIP-seq analysis showed that either USP11 KD or replacement of endogenous USP11 with a catalytic-inactive USP11 mutant significantly decreased chromatin binding by AR and c-Myc. We find that USP11 employs two mechanisms to up-regulate AR and c-Myc levels: namely, deubiquitination of AR and c-Myc proteins to increase their stability and deubiquitination of H2A-K119Ub, a repressive histone mark, on promoters of AR and c-Myc genes to increase their transcription. AR and c-Myc reexpression in USP11-KD PCa cells partly rescued cell growth defects. Thus, our studies reveal a tumor-promoting role for USP11 in aggressive PCa through upregulation of AR and c-Myc activities and support USP11 as a potential target against PCa.
Subject(s)
Disease Progression , Gene Expression Regulation, Neoplastic , Prostatic Neoplasms , Proto-Oncogene Proteins c-myc , Receptors, Androgen , Thiolester Hydrolases , Humans , Male , Cell Line, Tumor , Cell Proliferation/genetics , Histones/metabolism , Promoter Regions, Genetic/genetics , Prostatic Neoplasms/genetics , Prostatic Neoplasms/pathology , Prostatic Neoplasms/metabolism , Prostatic Neoplasms, Castration-Resistant/genetics , Prostatic Neoplasms, Castration-Resistant/metabolism , Prostatic Neoplasms, Castration-Resistant/pathology , Proto-Oncogene Proteins c-myc/metabolism , Proto-Oncogene Proteins c-myc/genetics , Receptors, Androgen/metabolism , Receptors, Androgen/genetics , Thiolester Hydrolases/metabolism , Thiolester Hydrolases/genetics , Ubiquitination , Up-RegulationABSTRACT
Over 45,000 gun deaths occur annually in the United States, a country with more than 100 million gun owners and more than 350 million guns. Nevertheless, passing legislation to reduce gun violence is difficult because the issue is intensely polarized. Polls asking about general gun policies (e.g., AR-15 restrictions) demonstrate that, at least in the abstract, Americans disagree vehemently about whether civilians should be able to keep and bear arms. It is possible, however, that a hidden consensus exists in America, which has thus far escaped attention-specifically, that when the focus is on their immediate environments and daily lives, even traditionally pro-gun groups may exhibit aversion to certain types of gun ownership and storage practices. To test this, we conducted two preregistered survey experiments with a large national sample. The first was a conjoint analysis where respondents chose between neighbors (n = 33,596 choices) who randomly varied on seven attributes, including gun ownership (none, pistol, AR-15). No group of respondents, not even traditionally pro-gun groups (e.g., Republicans), exhibited a significant preference for living near gun owners, and every group was averse to AR-15-owning neighbors. The second experiment, per debates about safe-storage laws, was a picture-based factorial vignette that randomized a neighbor's gun storage practices (n = 2,098). Every group of respondents was averse to interacting with a neighbor who stored guns outside of a locked safe. Our findings demonstrate that there is widespread agreement that certain types of gun ownership and storage practices are undesirable for communities.
Subject(s)
Firearms , Humans , United States , Surveys and Questionnaires , OwnershipABSTRACT
Androgen receptor splice variant 7 (AR-V7) is crucial for prostate cancer progression and therapeutic resistance. We show that, independent of ligand, AR-V7 binds both androgen-responsive elements (AREs) and non-canonical sites distinct from full-length AR (AR-FL) targets. Consequently, AR-V7 not only recapitulates AR-FL's partial functions but also regulates an additional gene expression program uniquely via binding to gene promoters rather than ARE enhancers. AR-V7 binding and AR-V7-mediated activation at these unique targets do not require FOXA1 but rely on ZFX and BRD4. Knockdown of ZFX or select unique targets of AR-V7/ZFX, or BRD4 inhibition, suppresses growth of castration-resistant prostate cancer cells. We also define an AR-V7 direct target gene signature that correlates with AR-V7 expression in primary tumors, differentiates metastatic prostate cancer from normal, and predicts poor prognosis. Thus, AR-V7 has both ARE/FOXA1 canonical and ZFX-directed non-canonical regulatory functions in the evolution of anti-androgen therapeutic resistance, providing information to guide effective therapeutic strategies.
Subject(s)
Alternative Splicing/genetics , Carcinogenesis/genetics , Kruppel-Like Transcription Factors/genetics , Oncogenes/genetics , Prostatic Neoplasms, Castration-Resistant/genetics , Receptors, Androgen/genetics , Animals , Cell Differentiation/genetics , Cell Line , Cell Line, Tumor , Drug Resistance, Neoplasm/genetics , Gene Expression Regulation, Neoplastic/genetics , HEK293 Cells , Hepatocyte Nuclear Factor 3-alpha/genetics , Humans , Male , Mice , Mice, Inbred NOD , Mice, SCID , Nuclear Proteins/genetics , Promoter Regions, Genetic/geneticsABSTRACT
Androgen receptor (AR) and its splice variants (AR-SVs) promote prostate cancer (PCa) growth by orchestrating transcriptional reprogramming. Mechanisms by which the low complexity and intrinsically disordered primary transactivation domain (AF-1) of AR and AR-SVs regulate transcriptional programming in PCa remains poorly defined. Using omics, live and fixed fluorescent microscopy of cells, and purified AF-1 and AR-V7 recombinant proteins we show here that AF-1 and the AR-V7 splice variant form molecular condensates by liquid-liquid phase separation (LLPS) that exhibit disorder characteristics such as rapid intracellular mobility, coactivator interaction, and euchromatin induction. The LLPS and other disorder characteristics were reversed by a class of small-molecule-selective AR-irreversible covalent antagonists (SARICA) represented herein by UT-143 that covalently and selectively bind to C406 and C327 in the AF-1 region. Interfering with LLPS formation with UT-143 or mutagenesis resulted in chromatin condensation and dissociation of AR-V7 interactome, all culminating in a transcriptionally incompetent complex. Biochemical studies suggest that C327 and C406 in the AF-1 region are critical for condensate formation, AR-V7 function, and UT-143's irreversible AR inhibition. Therapeutically, UT-143 possesses drug-like pharmacokinetics and metabolism properties and inhibits PCa cell proliferation and tumor growth. Our work provides critical information suggesting that clinically important AR-V7 forms transcriptionally competent molecular condensates and covalently engaging C327 and C406 in AF-1, dissolves the condensates, and inhibits its function. The work also identifies a library of AF-1-binding AR and AR-SV-selective covalent inhibitors for the treatment of PCa.
Subject(s)
Prostatic Neoplasms, Castration-Resistant , Prostatic Neoplasms , Male , Humans , Receptors, Androgen/metabolism , Cysteine , Prostatic Neoplasms/drug therapy , Prostatic Neoplasms/genetics , Prostatic Neoplasms/metabolism , Androgen Receptor Antagonists/pharmacology , Prostatic Neoplasms, Castration-Resistant/pathology , Cell Line, Tumor , Protein Isoforms/metabolismABSTRACT
Rubble piles asteroids consist of reassembled fragments from shattered monolithic asteroids and are much more abundant than previously thought in the solar system. Although monolithic asteroids that are a kilometer in diameter have been predicted to have a lifespan of few 100 million years, it is currently not known how durable rubble pile asteroids are. Here, we show that rubble pile asteroids can survive ambient solar system bombardment processes for extremely long periods and potentially 10 times longer than their monolith counterparts. We studied three regolith dust particles recovered by the Hayabusa space probe from the rubble pile asteroid 25143 Itokawa using electron backscatter diffraction, time-of-flight secondary ion mass spectrometry, atom probe tomography, and 40Ar/39Ar dating techniques. Our results show that the particles have only been affected by shock pressure of ca. 5 to 15 GPa. Two particles have 40Ar/39Ar ages of 4,219 ± 35 and 4,149 ± 41 My and when combined with thermal and diffusion models; these results constrain the formation age of the rubble pile structure to ≥4.2 billion years ago. Such a long survival time for an asteroid is attributed to the shock-absorbent nature of rubble pile material and suggests that rubble piles are hard to destroy once they are created. Our results suggest that rubble piles are probably more abundant in the asteroid belt than previously thought and provide constrain to help develop mitigation strategies to prevent asteroid collisions with Earth.
Subject(s)
Dust , Earth, Planet , Diffusion , Electrons , LongevityABSTRACT
Androgen receptor (AR) is one of the key targets for the treatment of castration-resistant prostate cancer (CRPC). Current endocrine therapy can greatly improve patients with CRPC. However, with the change of pathogenic mechanism, acquired resistance often leads to the failure of treatment. Studies have shown that tanshinone IIA (TS-IIA) and its derivatives have significant antitumor activity, and have certain AR-targeting effects, but the mechanism is unknown. In this study, the TS-IIA analog TB3 was found to significantly inhibit the growth of CRPC in vitro and in vivo. Molecular docking, cellular thermal shift assay, and cycloheximide experiments confirmed that AR was the target of TB3 and promoted the degradation of AR. Furthermore, TB3 can significantly inhibit glycolysis metabolism by targeting the AR/PKM2 axis. The addition of pyruvic acid could significantly alleviate the inhibitory effect of TB3 on CRPC cells. Besides, the knockdown of AR or PKM2 also could reverse the effect of TB3 on CRPC cells. Taken together, our study suggests that TS-IIA derivative TB3 inhibits glycolysis to prevent the CRPC process by targeting the AR/PKM2 axis.
Subject(s)
Abietanes , Glycolysis , Prostatic Neoplasms, Castration-Resistant , Receptors, Androgen , Thyroid Hormone-Binding Proteins , Animals , Humans , Male , Mice , Abietanes/pharmacology , Carrier Proteins/metabolism , Carrier Proteins/genetics , Cell Line, Tumor , Cell Proliferation/drug effects , Glycolysis/drug effects , Membrane Proteins/metabolism , Membrane Proteins/genetics , Mice, Nude , Prostatic Neoplasms, Castration-Resistant/metabolism , Prostatic Neoplasms, Castration-Resistant/pathology , Prostatic Neoplasms, Castration-Resistant/drug therapy , Receptors, Androgen/metabolism , Receptors, Androgen/genetics , Thyroid Hormones/metabolismABSTRACT
Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the most common cause of dementia among the elderly population. Despite its widespread prevalence, our comprehension of the intricate mechanisms governing the pathogenesis of the disease remains incomplete, posing a challenge for the development of efficient therapies. Pathologically characterized by the presence of amyloid ß plaques and neurofibrillary tau tangles, AD is also accompanied by the hyperactivation of glial cells and the immune system. The complement cascade, the evolutionarily conserved innate immune pathway, has emerged as a significant contributor to AD. This review focuses on one of the complement components, the C3a receptor (C3aR), covering its structure, ligand-receptor interaction, intracellular signaling and its functional consequences. Drawing insights from cellular and AD mouse model studies, we present the multifaceted role of complement C3aR signaling in AD and attempt to convey to the readers that C3aR acts as a crucial immune and metabolic modulator to influence AD pathogenesis. Building on this framework, the objective of this review is to inform future research endeavors and facilitate the development of therapeutic strategies for this challenging condition.
Subject(s)
Alzheimer Disease , Receptors, Complement , Signal Transduction , Alzheimer Disease/immunology , Alzheimer Disease/metabolism , Humans , Animals , Signal Transduction/immunology , Receptors, Complement/metabolism , Receptors, Complement/immunology , Mice , Immunity, Innate , Disease Models, AnimalABSTRACT
Stromal-epithelial communication is an absolute necessity when it comes to the morphogenesis and pathogenesis of solid tissues, including the prostate and breast. So far, signalling pathways of several growth factors have been investigated. Besides such chemical factors, non-coding RNAs such as miRNAs have recently gained much interest because of their variety and complexity of action. Prostate and breast tissues being highly responsive to steroid hormones such as androgen and estrogen, respectively, it is not surprising that a huge set of available literature critically investigated the interplay between such hormones and miRNAs, especially in carcinogenesis. This review showcases our effort to highlight hormonally-related miRNAs that also somehow perturb the regular stromal-epithelial interactions during carcinogenesis in the prostate and breast. In future, we look forward to exploring how hormonal changes in the tissue microenvironment bring about miRNA-mediated changes in stromal-epithelial interactome in carcinogenesis and cancer progression.
Subject(s)
Breast Neoplasms , MicroRNAs , Prostatic Neoplasms , Stromal Cells , Humans , MicroRNAs/genetics , MicroRNAs/metabolism , Prostatic Neoplasms/genetics , Prostatic Neoplasms/pathology , Prostatic Neoplasms/metabolism , Male , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Breast Neoplasms/metabolism , Stromal Cells/metabolism , Stromal Cells/pathology , Female , Epithelial Cells/metabolism , Epithelial Cells/pathology , Cell Communication/genetics , Animals , Tumor Microenvironment/genetics , Gene Expression Regulation, NeoplasticABSTRACT
The emergence of AR-V7, a truncated isoform of AR upon androgen deprivation therapy treatment, leads to the development of castration resistant prostate cancer (CRPC). Understanding mechanisms that regulate AR-V7 expression is critical for developing newer therapeutic strategies. In this study, we have investigated the regulation of AR-V7 during cell cycle and identified a distinct pattern of periodic fluctuation, peaking during G2/M phase. This fluctuation correlates with the expression of Cdc-2 like kinase 1 (CLK1) and phosphorylated serine/arginine-rich splicing factor 1 (p-SRSF1) during these phases, pointing towards their role in AR-V7 generation. Functional assays reveal that CLK1 knockdown prolongs the S phase, leading to altered cell cycle distribution and increased accumulation of AR-V7 and pSRSF1 in G1/S phase. Conversely, CLK1 overexpression rescues AR-V7 and p-SRSF1 levels in the G2/M phase, consistent with observed cell cycle alterations upon AR-V7 knockdown and overexpression in CRPC cells. Furthermore, overexpression of kinase-deficient CLK1 mutant leads to diminished AR-V7 levels during G2/M, underlining the essential contribution of CLK1's kinase activity in modulating AR-V7 expression. Collectively, our findings, for the first time, show periodic regulation of AR-V7 expression, its effect on cell cycle progression and the critical role of CLK1-pSRSF1 axis in modulating AR-V7 expression throughout the cell cycle.
Subject(s)
G2 Phase Cell Cycle Checkpoints , Prostatic Neoplasms, Castration-Resistant , Receptors, Androgen , Humans , Male , Cell Line, Tumor , Cell Proliferation/genetics , G2 Phase/genetics , G2 Phase Cell Cycle Checkpoints/genetics , Gene Expression Regulation, Neoplastic , Phosphorylation , Prostatic Neoplasms, Castration-Resistant/genetics , Prostatic Neoplasms, Castration-Resistant/pathology , Prostatic Neoplasms, Castration-Resistant/metabolism , Protein Isoforms/genetics , Protein Isoforms/metabolism , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Protein-Tyrosine Kinases/metabolism , Protein-Tyrosine Kinases/genetics , Receptors, Androgen/metabolism , Receptors, Androgen/genetics , Serine-Arginine Splicing Factors/metabolism , Serine-Arginine Splicing Factors/geneticsABSTRACT
Chondrocyte ferroptosis induces the occurrence of osteoarthritis (OA). As a key gene of OA, C5a receptor 1 (C5AR1) is related to ferroptosis. Here, we investigated whether C5AR1 interferes with chondrocyte ferroptosis during OA occurrence. C5AR1 was downregulated in PA-treated chondrocytes. Overexpression of C5AR1 increased the cell viability and decreased ferroptosis in chondrocytes. Moreover, Tumor necrosis factor superfamily member 13B (TNFSF13B) was downregulated in PA-treated chondrocytes, and knockdown of TNFSF13B eliminated the inhibitory effect of C5AR1 on ferroptosis in chondrocytes. More importantly, the PI3K/Akt/GSK3ß/Nrf2/HO-1 pathway inhibitor LY294002 reversed the inhibition of C5AR1 or TNFSF13B on ferroptosis in chondrocytes. Finally, we found that C5AR1 alleviated joint tissue lesions and ferroptosis in rats and inhibited the progression of OA in the rat OA model constructed by anterior cruciate ligament transection (ACLT), which was reversed by interfering with TNFSF13B. This study shows that C5AR1 reduces the progression of OA by upregulating TNFSF13B to activate the PI3K/Akt/GSK3ß/Nrf2/HO-1 pathway and thereby inhibiting chondrocyte sensitivity to ferroptosis, indicating that C5AR1 may be a potential therapeutic target for ferroptosis-related diseases.
Subject(s)
Chondrocytes , Ferroptosis , Glycogen Synthase Kinase 3 beta , NF-E2-Related Factor 2 , Osteoarthritis , Phosphatidylinositol 3-Kinases , Proto-Oncogene Proteins c-akt , Rats, Sprague-Dawley , Receptor, Anaphylatoxin C5a , Animals , Ferroptosis/drug effects , Proto-Oncogene Proteins c-akt/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Chondrocytes/metabolism , Chondrocytes/pathology , Chondrocytes/drug effects , NF-E2-Related Factor 2/metabolism , NF-E2-Related Factor 2/genetics , Rats , Osteoarthritis/metabolism , Osteoarthritis/pathology , Osteoarthritis/genetics , Glycogen Synthase Kinase 3 beta/metabolism , Glycogen Synthase Kinase 3 beta/genetics , Male , Receptor, Anaphylatoxin C5a/metabolism , Receptor, Anaphylatoxin C5a/genetics , Signal Transduction , Heme Oxygenase-1/metabolism , Heme Oxygenase-1/genetics , Heme Oxygenase (Decyclizing)ABSTRACT
Podocytes are essential to maintaining the integrity of the glomerular filtration barrier, but they are frequently affected in lupus nephritis (LN). Here, we show that the significant upregulation of Drp1S616 phosphorylation in podocytes promotes mitochondrial fission, leading to mitochondrial dysfunction and podocyte injury in LN. Inhibition or knockdown of Drp1 promotes mitochondrial fusion and protects podocytes from injury induced by LN serum. In vivo, pharmacological inhibition of Drp1 reduces the phosphorylation of Drp1S616 in podocytes in lupus-prone mice. Podocyte injury is reversed when Drp1 is inhibited, resulting in the alleviation of proteinuria. Mechanistically, complement component C5a (C5a) upregulates the phosphorylation of Drp1S616 and promotes mitochondrial fission in podocytes. Moreover, the expression of C5a receptor 1 (C5aR1) is notably upregulated in podocytes in LN. C5a-C5aR1 axis-controlled phosphorylation of Drp1S616 and mitochondrial fission are substantially suppressed when C5aR1 is knocked down by siRNA. Moreover, lupus-prone mice treated with C5aR inhibitor show reduced phosphorylation of Drp1S616 in podocytes, resulting in significantly less podocyte damage. Together, this study uncovers a novel mechanism by which the C5a-C5aR1 axis promotes podocyte injury by enhancing Drp1-mediated mitochondrial fission, which could have significant implications for the treatment of LN.
Subject(s)
Complement C5a , Dynamins , Lupus Nephritis , Mitochondrial Dynamics , Podocytes , Receptor, Anaphylatoxin C5a , Podocytes/metabolism , Podocytes/pathology , Lupus Nephritis/metabolism , Lupus Nephritis/pathology , Lupus Nephritis/etiology , Animals , Receptor, Anaphylatoxin C5a/metabolism , Receptor, Anaphylatoxin C5a/genetics , Mice , Dynamins/metabolism , Dynamins/genetics , Complement C5a/metabolism , Humans , Phosphorylation , Disease Models, Animal , Mitochondria/metabolism , Signal Transduction , FemaleABSTRACT
Parkinson's disease (PD) is a common and incurable neurodegenerative disorder that arises from the loss of dopaminergic neurons in the substantia nigra and is mainly characterized by progressive loss of motor function. Monogenic familial PD is associated with highly penetrant variants in specific genes, notably the PRKN gene, where homozygous or compound heterozygous loss-of-function variants predominate. PRKN encodes Parkin, an E3 ubiquitin-protein ligase important for protein ubiquitination and mitophagy of damaged mitochondria. Accordingly, Parkin plays a central role in mitochondrial quality control but is itself also subject to a strict protein quality control system that rapidly eliminates certain disease-linked Parkin variants. Here, we summarize the cellular and molecular functions of Parkin, highlighting the various mechanisms by which PRKN gene variants result in loss-of-function. We emphasize the importance of high-throughput assays and computational tools for the clinical classification of PRKN gene variants and how detailed insights into the pathogenic mechanisms of PRKN gene variants may impact the development of personalized therapeutics.
Subject(s)
Parkinson Disease , Ubiquitin-Protein Ligases , Humans , Ubiquitin-Protein Ligases/genetics , Ubiquitin-Protein Ligases/metabolism , Parkinson Disease/genetics , Parkinson Disease/pathology , Parkinson Disease/metabolism , Mitochondria/metabolism , Mitochondria/genetics , Mitochondria/pathology , Ubiquitination/genetics , Mitophagy/genetics , AnimalsABSTRACT
Androgen receptor (AR) messenger RNA (mRNA) alternative splicing variants (AR-Vs) are implicated in castration-resistant progression of prostate cancer (PCa), although the molecular mechanism underlying the genesis of AR-Vs remains poorly understood. The CDK12 gene is often deleted or mutated in PCa and CDK12 deficiency is known to cause homologous recombination repair gene alteration or BRCAness via alternative polyadenylation (APA). Here, we demonstrate that pharmacological inhibition or genetic inactivation of CDK12 induces AR gene intronic (intron 3) polyadenylation (IPA) usage, AR-V expression, and PCa cell resistance to the antiandrogen enzalutamide (ENZ). We further show that AR binds to the CCNK gene promoter and up-regulates CYCLIN K expression. In contrast, ENZ decreases AR occupancy at the CCNK gene promoter and suppresses CYCLIN K expression. Similar to the effect of the CDK12 inhibitor, CYCLIN K degrader or ENZ treatment promotes AR gene IPA usage, AR-V expression, and ENZ-resistant growth of PCa cells. Importantly, we show that targeting BRCAness induced by CYCLIN K down-regulation with the PARP inhibitor overcomes ENZ resistance. Our findings identify CYCLIN K down-regulation as a key driver of IPA usage, hormonal therapy-induced AR-V expression, and castration resistance in PCa. These results suggest that hormonal therapy-induced AR-V expression and therapy resistance are vulnerable to PARP inhibitor treatment.
Subject(s)
Antineoplastic Agents , Cyclins , Poly(ADP-ribose) Polymerase Inhibitors , Prostatic Neoplasms, Castration-Resistant , Receptors, Androgen , Androgen Antagonists/pharmacology , Antineoplastic Agents/pharmacology , Benzamides/pharmacology , Cell Line, Tumor , Cyclins/genetics , Down-Regulation , Drug Resistance, Neoplasm/genetics , Humans , Introns , Male , Nitriles/pharmacology , Phenylthiohydantoin/pharmacology , Poly(ADP-ribose) Polymerase Inhibitors/pharmacology , Polyadenylation/genetics , Prostatic Neoplasms, Castration-Resistant/drug therapy , Prostatic Neoplasms, Castration-Resistant/genetics , RNA, Messenger/genetics , Receptors, Androgen/geneticsABSTRACT
ß-adrenergic receptor (ß-AR) signaling plays predominant roles in modulating energy expenditure by triggering lipolysis and thermogenesis in adipose tissue, thereby conferring obesity resistance. Obesity is associated with diminished ß3-adrenergic receptor (ß3-AR) expression and decreased ß-adrenergic responses, but the molecular mechanism coupling nutrient overload to catecholamine resistance remains poorly defined. Ten-eleven translocation (TET) proteins are dioxygenases that alter the methylation status of DNA by oxidizing 5-methylcytosine to 5-hydroxymethylcytosine and further oxidized derivatives. Here, we show that TET proteins are pivotal epigenetic suppressors of ß3-AR expression in adipocytes, thereby attenuating the responsiveness to ß-adrenergic stimulation. Deletion of all three Tet genes in adipocytes led to increased ß3-AR expression and thereby enhanced the downstream ß-adrenergic responses, including lipolysis, thermogenic gene induction, oxidative metabolism, and fat browning in vitro and in vivo. In mouse adipose tissues, Tet expression was elevated after mice ate a high-fat diet. Mice with adipose-specific ablation of all TET proteins maintained higher levels of ß3-AR in both white and brown adipose tissues and remained sensitive to ß-AR stimuli under high-fat diet challenge, leading to augmented energy expenditure and decreased fat accumulation. Consequently, they exhibited improved cold tolerance and were substantially protected from diet-induced obesity, inflammation, and metabolic complications, including insulin resistance and hyperlipidemia. Mechanistically, TET proteins directly repressed ß3-AR transcription, mainly in an enzymatic activity-independent manner, and involved the recruitment of histone deacetylases to increase deacetylation of its promoter. Thus, the TET-histone deacetylase-ß3-AR axis could be targeted to treat obesity and related metabolic diseases.
Subject(s)
Epigenesis, Genetic , Gene Expression Regulation , Proto-Oncogene Proteins , Adipose Tissue, Brown/metabolism , Animals , Gene Expression Regulation/genetics , Mice , Obesity/genetics , Obesity/metabolism , Proto-Oncogene Proteins/genetics , Receptors, Adrenergic, beta/genetics , Receptors, Adrenergic, beta/metabolism , Receptors, Adrenergic, beta-3/genetics , Receptors, Adrenergic, beta-3/metabolism , Thermogenesis/geneticsABSTRACT
Androgen receptor (AR) signaling is crucial for driving prostate cancer (PCa), the most diagnosed and the second leading cause of death in male patients with cancer in the United States. Androgen deprivation therapy is initially effective in most instances of AR-positive advanced or metastatic PCa. However, patients inevitably develop lethal castration-resistant PCa (CRPC), which is also resistant to the next-generation AR signaling inhibitors. Most CRPCs maintain AR expression, and blocking AR signaling remains a main therapeutic approach. GATA2 is a pioneer transcription factor emerging as a key therapeutic target for PCa because it promotes AR expression and activation. While directly inhibiting GATA2 transcriptional activity remains challenging, enhancing GATA2 degradation is a plausible therapeutic strategy. How GATA2 protein stability is regulated in PCa remains unknown. Here, we show that constitutive photomorphogenesis protein 1 (COP1), an E3 ubiquitin ligase, drives GATA2 ubiquitination at K419/K424 for degradation. GATA2 lacks a conserved [D/E](x)xxVP[D/E] degron but uses alternate BR1/BR2 motifs to bind COP1. By promoting GATA2 degradation, COP1 inhibits AR expression and activation and represses PCa cell and xenograft growth and castration resistance. Accordingly, GATA2 overexpression or COP1 mutations that disrupt COP1-GATA2 binding block COP1 tumor-suppressing activities. We conclude that GATA2 is a major COP1 substrate in PCa and that COP1 promotion of GATA2 degradation is a direct mechanism for regulating AR expression and activation, PCa growth, and castration resistance.