Structure and mechanism of the Hsp90 molecular chaperone machinery

Chaperone directed heterobifunctional molecules circumvent KRASG12C inhibitor resistance

While KRASG12C inhibitors have shown promising results in clinical activity, acquired resistance remains a significant barrier to durable responses. Combination therapies have been explored to improve the efficacy of KRASG12C inhibitors; however, their use is often restricted due to toxicity and limitations in clinically amenable dosing schedules. Transcriptomic profiling and functional assays on acquired resistant models to adagrasib identified an enrichment of HSP90 client proteins in resistant phenotypes, suggesting a therapeutic vulnerability. To address the finding, RNK07421, a novel heterobifunctional molecule, was developed to simultaneously target KRASG12C and HSP90-client oncoproteins. Structural and biochemical analyses demonstrated that RNK07421 disrupts KRASG12C interactions by inducing a non-natural interface with HSP90, thereby impairing oncogenic signaling. In vitro, RNK07421 effectively suppressed ERK reactivation and reduced viability in KRASG12C-mutant cell lines exhibiting either intrinsic or acquired resistance. In vivo, RNK07421 significantly reduced tumor burden in xenograft models, outperforming both monotherapies and combination therapies. These findings highlight dual KRASG12C and HSP90 inhibition as a promising strategy to overcome resistance in KRASG12C-driven cancers.

Benzbromarone interferes with the interaction between Hsp90 and Aha1 by interacting with both of them

Aha1 is one of the well-known co-chaperones of Hsp90. However, the action mode of Aha1 has not been fully elucidated yet, and the binding mode of Aha1's C-terminal domain (Aha1-CTD) to Hsp90 is still under discussion. Meanwhile, since both Hsp90 and Aha1 contribute to tumorigenesis through controlling the homeostasis of onco-proteins, Hsp90-Aha1 system might serve as a target for anti-tumor drug development. A few of active compounds towards Hsp90-Aha1 system have been reported during the past years, but no compound binding pocket in Aha1 was pictured yet. Here in this manuscript, by using the discovered dual-modulator Benzbromarone as the probe, the pocket in Aha1 responsible for compound recognition is defined. Interestingly, as shown by the cryo-EM structures of Hsp90:Aha1 system, it is the same pocket that is involved in the in vitro interaction between Aha1-CTD and Hsp90-MD. Besides, Benzbromarone's binding to Hsp90-NTD also exhibits unique structural features. Not surprisingly, due to the interference with the Hsp90 machinery, Benzbromarone could down-regulate the ATPase activity of the chaperone. Finally, according to the cellular-based experimental data, Benzbromarone has been shown to exhibit cytotoxicity against multiple cancer cell types, at least in part, through its modulation of the Hsp90 system.

Epichaperomes: redefining chaperone biology and therapeutic strategies in complex diseases

The complexity of disease biology extends beyond mutations or overexpression, encompassing stress-induced mechanisms that reshape proteins into pathological assemblies. Epichaperomes, stable and disease-specific assemblies of chaperones and co-chaperones, exemplify this phenomenon. This review emphasizes the critical structural and functional distinctions between epichaperomes and canonical chaperones, highlighting their role in redefining therapeutic strategies. Epichaperomes arise under stress conditions through post-translational modifications that stabilize these assemblies, enabling them to act as scaffolding platforms that rewire protein-protein interaction networks and drive the pathological phenotypes of complex diseases such as cancer and neurodegeneration. Chemical biology has been instrumental in uncovering the unique nature of epichaperomes, with small molecules like PU-H71 elucidating their biology and demonstrating their therapeutic potential by dismantling pathological scaffolds and restoring normal protein-protein interaction networks. By targeting epichaperomes, we unlock the potential for network-level interventions and personalized medicine, offering transformative possibilities for diseases driven by protein-protein interaction network dysregulation.

Pharmacological intervention for chronic phase of spinal cord injury

Spinal cord injury is an intractable traumatic injury. The most common hurdles faced during spinal cord injury are failure of axonal regrowth and reconnection to target sites. These also tend to be the most challenging issues in spinal cord injury. As spinal cord injury progresses to the chronic phase, lost motor and sensory functions are not recovered. Several reasons may be attributed to the failure of recovery from chronic spinal cord injury. These include factors that inhibit axonal growth such as activated astrocytes, chondroitin sulfate proteoglycan, myelin-associated proteins, inflammatory microglia, and fibroblasts that accumulate at lesion sites. Skeletal muscle atrophy due to denervation is another chronic and detrimental spinal cord injury-specific condition. Although several intervention strategies based on multiple outlooks have been attempted for treating spinal cord injury, few approaches have been successful. To treat chronic spinal cord injury, neural cells or tissue substitutes may need to be supplied in the cavity area to enable possible axonal growth. Additionally, stimulating axonal growth activity by extrinsic factors is extremely important and essential for maintaining the remaining host neurons and transplanted neurons. This review focuses on pharmacotherapeutic approaches using small compounds and proteins to enable axonal growth in chronic spinal cord injury. This review presents some of these candidates that have shown promising outcomes in basic research ( in vivo animal studies) and clinical trials: AA-NgR(310)ecto-Fc (AXER-204), fasudil, phosphatase and tensin homolog protein antagonist peptide 4, chondroitinase ABC, intracellular sigma peptide, (-)-epigallocatechin gallate, matrine, acteoside, pyrvate kinase M2, diosgenin, granulocyte-colony stimulating factor, and fampridine-sustained release. Although the current situation suggests that drug-based therapies to recover function in chronic spinal cord injury are limited, potential candidates have been identified through basic research, and these candidates may be subjects of clinical studies in the future. Moreover, cocktail therapy comprising drugs with varied underlying mechanisms may be effective in treating the refractory status of chronic spinal cord injury.

What can go wrong for future Senegalese sole recruitment? Temperature and food availability as important drivers of early-life-history traits

Water temperature and prey availability are key factors influencing the successful recruitment of early life stages in fish. Understanding how these variables modulate larval growth and survival is essential for modelling larval dynamics. In this study we reared S. senegalensis larvae under controlled laboratory conditions to assess the effects of temperature and feeding frequency on larval development. Three temperatures (17, 20, and 23 °C) and three feeding frequencies (Ff 2.5 fed 2.5 times per week, Ff 4 four times per week, and Ff 6 six times per week) were tested from 12 to 32 days post-hatch (dph) in both individual and group housing systems. Survival, growth, and metamorphosis progress were monitored, and the expression of six genes related to nutrition (tryp1a and apoA4Aa2), cellular stress (hsp90aa and hsp70), endocrine regulation (tgb), and muscle development (myf4) were monitored on S3 and S4 metamorphic larvae. The feeding frequency appeared as the primary driver influencing all investigated traits, while temperature played a less pronounced effect. These data demonstrate the critical role of energy provision in regulating growth, development, and survival, which interacts with temperature, particularly under conditions where metabolic and energy demands cannot be fully fulfilled. Additionally, the Senegalese sole larvae exhibited compensatory genomic adaptive responses to efficiently mobilize nutrients from the gut and adjust the thyroid axis and cellular responses to support metamorphosis transformation and metabolism when food availability was limited or when temperature approached physiological thresholds.

The Hsp90β Isoform: An Attractive Target for Drug Development

The beta isoform of 90 kDa heat shock protein (Hsp90β) plays a critical role in maintaining cellular proteostasis by assisting in the folding and refolding of proteins, which is essential for both normal cellular function and stress response. It is constitutively expressed in mammalian cells, differentiating it from the inducible Hsp90α isoform. Hsp90β's involvement in diverse cellular processes, such as signal transduction, cell cycle control, and apoptosis, underscores its significant role in various diseases, including cancer and neurodegenerative disorders. The isoform-specific functions of Hsp90β and its interaction with unique client proteins make it a promising target for therapeutic intervention, particularly in the development of selective inhibitors that avoid the adverse effects observed with pan-Hsp90 inhibitors. This review delves into the structural and functional intricacies of Hsp90β, its role in disease, and the potential for selective drug development.

Advances in the structures, mechanisms and targeting of molecular chaperones

Molecular chaperones, a class of complex client regulatory systems, play significant roles in the prevention of protein misfolding and abnormal aggregation, the modulation of protein homeostasis, and the protection of cells from damage under constantly changing environmental conditions. As the understanding of the biological mechanisms of molecular chaperones has increased, their link with the occurrence and progression of disease has suggested that these proteins are promising targets for therapeutic intervention, drawing intensive interest. Here, we review recent advances in determining the structures of molecular chaperones and heat shock protein 90 (HSP90) chaperone system complexes. We also describe the features of molecular chaperones and shed light on the complicated regulatory mechanism that operates through interactions with various co-chaperones in molecular chaperone cycles. In addition, how molecular chaperones affect diseases by regulating pathogenic proteins has been thoroughly analyzed. Furthermore, we focus on molecular chaperones to systematically discuss recent clinical advances and various drug design strategies in the preclinical stage. Recent studies have identified a variety of novel regulatory strategies targeting molecular chaperone systems with compounds that act through different mechanisms from those of traditional inhibitors. Therefore, as more novel design strategies are developed, targeting molecular chaperones will significantly contribute to the discovery of new potential drugs.

3,5-Disubstituted pyrazoline as a promising core for anticancer agents: mechanisms of action and therapeutic potentials

The rapidly growing interest in the literature about the anticancer activity of 3,5-disubstituted pyrazolines and their promising therapeutic potentials/pharmacological properties, supported by the number of pyrazoline derivatives currently in clinical use or clinical trials, encouraged us to review the in vitro antiproliferative effects and biochemical investigations of probable mechanisms of action. Nevertheless, many reported pyrazoline-bearing compounds have anticancer activity without an explored mode of action, which opens new research avenues to examine their biochemical profiles further. Therefore, 3,5-disubstituted pyrazoline is a promising core that can be used to design new derivatives with anticancer activity based on the structure-activity relationship summarized in this review to obtain higher potency and selectivity.

Targeting Hsp90α to inhibit HMGB1-mediated renal inflammation and fibrosis

Renal fibrosis, a terminal manifestation of chronic kidney disease, is characterized by uncontrolled inflammatory responses, increased oxidative stress, tubular cell death, and imbalanced deposition of extracellular matrix. 5,2'-Dibromo-2,4',5'-trihydroxydiphenylmethanone (LM49), a polyphenol derivative synthesized by our group with excellent anti-inflammatory pharmacological properties, has been identified as a small-molecule inducer of extracellular matrix degradation. Nonetheless, the protective effects and mechanisms of LM49 on renal fibrosis remain unknown. Here, we report LM49 could effectively alleviate renal fibrosis and improve filtration function. Furthermore, LM49 significantly inhibited macrophage infiltration, pro-inflammatory cytokine production and oxidative stress. Interestingly, in HK-2 cells induced by tumour necrosis factor alpha under oxygen-glucose-serum deprivation conditions, LM49 treatment similarly yielded a reduced inflammatory response, elevated cellular viability and suppressed cell necrosis and epithelial-to-mesenchymal transition. Notably, LM49 prominently suppressed the high-mobility group box 1 (HMGB1) expression, nucleocytoplasmic translocation and activation. Mechanistically, drug affinity responsive target stability and cellular thermal shift assay confirmed that LM49 could interact with the target heat shock protein 90 alpha family class A member 1 (Hsp90α), disrupting the direct binding of Hsp90α to HMGB1 and inhibiting the nuclear export of HMGB1, thereby suppressing the inflammatory response, cell necrosis and fibrogenesis. Furthermore, molecular docking and molecular dynamic simulation revealed that LM49 occupied the N-terminal ATP pocket of Hsp90α. Collectively, our findings show that LM49 treatment can ameliorate renal fibrosis through inhibition of HMGB1-mediated inflammation and necrosis via binding to Hsp90α, providing strong evidence for its anti-inflammatory and anti-fibrotic actions.

Mechanisms of Azole Potentiation: Insights from Drug Repurposing Approaches

The emergence of azole resistance and tolerance in pathogenic fungi has emerged as a significant public health concern, emphasizing the urgency for innovative strategies to bolster the efficacy of azole-based treatments. Drug repurposing stands as a promising and practical avenue for advancing antifungal therapy, with the potential for swift clinical translation. This review offers a comprehensive overview of azole synergistic agents uncovered through drug repurposing strategies, alongside an in-depth exploration of the mechanisms by which these agents augment azole potency. Drawing from these mechanisms, we delineate strategies aimed at enhancing azole effectiveness, such as inhibiting efflux pumps to elevate azole concentrations within fungal cells, intensifying ergosterol synthesis inhibition, mitigating fungal cell resistance to azoles, and disrupting biological processes extending beyond ergosterol synthesis. This review is beneficial for the development of these potentiators, as it meticulously examines instances and provides nuanced discussions on the mechanisms underlying the progression of azole potentiators through drug repurposing strategies.

CO2 potentiates echinocandin efficacy during invasive candidiasis therapy via dephosphorylation of Hsp90 by Ptc2 in condensates

Carbon dioxide is a signaling cue critical for fungal pathogenesis. Ptc2, a type 2C protein phosphatase (PP2C), serves as a conserved CO2 sensor in fungi. By combining phosphoproteomic and biochemical assays, we identified Hsp90 as a direct target of Ptc2 at host CO2 concentrations and Ssb1 as a Ptc2 target protein regardless of CO2 levels in Candida albicans, the most prevalent human fungal pathogen. Ptc2 forms reversible condensates at elevated CO2, which enables the recruitment of Hsp90, but not Ssb1, to condensates, allowing efficient dephosphorylation. This process confers an enhanced susceptibility to caspofungin in vitro and during in vivo infection therapy. Importantly, we demonstrate this phenomenon in non-albicans Candida species. Sequential passages of C. albicans in mice with caspofungin treatment readily induce in vivo drug tolerance, causing therapeutic failure. These evolved strains display increased resistance to caspofungin under host concentrations of CO2 but remain susceptible in air. Collectively, our study reveals a profound impact of host concentrations of CO2 on antifungal drug susceptibility and connects this phenotype to therapeutic outcomes and highlights condensate formation as an efficient means that enables selective recruitment of substrates for certain signaling events.

Thermal Titration Molecular Dynamics: The Revenge of the Fragments

During the last 20 years, the fragment-based drug discovery approach gained popularity in both industrial and academic settings due to its efficient exploration of the chemical space. This bottom-up approach relies on identifying high-efficiency small ligands (fragments) that bind to a target binding site and then rationally evolve them into mature druglike compounds. To achieve such a task, researchers rely on accurate information about the ligand binding mode, usually obtained through experimental techniques, such as X-ray crystallography or computer simulations. However, the physicochemical characteristics of fragments limit the accuracy and reliability of computational predictions of their binding mode. This article presents a new Thermal Titration Molecular Dynamics (TTMD) protocol, a recently developed enhanced sampling method for qualitatively estimating protein-ligand-binding stability, specifically tuned for the refinement of fragment docking results. The protocol has been applied to eight pharmaceutically relevant targets on 12 different test cases, including ligands with very low molecular weight and structural complexity (MiniFrag/FragLites). In more than 80% of cases, TTMD successfully identified the native fragment binding mode among a set of docking poses, outperforming docking alone and proving to be a useful tool to assist the fragment screening and optimization process.

The Effect of Heat Stress on Wheat Flag Leaves Revealed by Metabolome and Transcriptome Analyses During the Reproductive Stage

In this study, we were dedicated to investigating the effect caused by heat stress on wheat flag leaves. Metabolome and transcriptome analysis were introduced to identify some key biological processes. As a result, 182 and 214 metabolites were significantly changed at the anthesis and post-anthesis stages, respectively; most of them were lipids, amino acids and derivatives, phenolic acids, and alkaloids. Aminoacyl-tRNA biosynthesis was the most significantly enriched pathway by metabolites at both two stages, each of which included 13 types of amino acid, and 12 of them were shared and up-regulated. Therefore, we further measured 22 kinds of amino acid content in ten different wheat genotypes at the post-anthesis stage. Based on the average content of each amino acid, 17 kinds of them were significantly increased after heat stress, and 4 types were significantly decreased. Both the metabolism analysis and the transcriptome analysis had a higher number of significantly changed metabolites or differential expressed genes at the post-anthesis stage, which indicated that the post-anthesis stage is more sensitive to heat stress, with 21,361 and 17,130 differential expressed genes, respectively. Two pathways, protein processing in endoplasmic reticulum and ABC transporters, were significantly enriched at two stages. The differential expressed genes in processing in endoplasmic reticulum pathway mainly encoded various types of molecular chaperones; among them, the HSP20 family was the most predominant and intensively up-regulated. The ABC transporter gene family is another pathway that is deeply involved in heat-stress response, which could be classified into five subfamilies; among them, subfamilies B and G were the most active. In summary, this study revealed the heat response pattern of amino acids, HSPs, and ABC transporter which may play a vital role during the wheat reproductive stage.

Interplay of p23 with FKBP51 and their chaperone complex in regulating tau aggregation

The pathological deposition of tau and amyloid-beta into insoluble amyloid fibrils are pathological hallmarks of Alzheimer's disease. Molecular chaperones are important cellular factors contributing to the regulation of tau misfolding and aggregation. Here we reveal an Hsp90-independent mechanism by which the co-chaperone p23 as well as a molecular complex formed by two co-chaperones, p23 and FKBP51, modulates tau aggregation. Integrating NMR spectroscopy, SAXS, molecular docking, and site-directed mutagenesis we reveal the structural basis of the p23-FKBP51 complex. We show that p23 specifically recognizes the TPR domain of FKBP51 and interacts with tau through its C-terminal disordered tail. We further show that the p23-FKBP51 complex binds tau to form a dynamic p23-FKBP51-tau trimeric complex that delays tau aggregation and thus may counteract Hsp90-FKBP51 mediated toxicity. Taken together, our findings reveal a co-chaperone mediated Hsp90-independent chaperoning of tau protein.

Computer-aided Drug Discovery Approaches in the Identification of Anticancer Drugs from Natural Products: A Review

Natural plant sources are essential in the development of several anticancer drugs, such as vincristine, vinblastine, vinorelbine, docetaxel, paclitaxel, camptothecin, etoposide, and teniposide. However, various chemotherapies fail due to adverse reactions, drug resistance, and target specificity. Researchers are now focusing on developing drugs that use natural compounds to overcome these issues. These drugs can affect multiple targets, have reduced adverse effects, and are effective against several cancer types. Developing a new drug is a highly complex, expensive, and time-consuming process. Traditional drug discovery methods take up to 15 years for a new medicine to enter the market and cost more than one billion USD. However, recent Computer Aided Drug Discovery (CADD) advancements have changed this situation. This paper aims to comprehensively describe the different CADD approaches in identifying anticancer drugs from natural products. Data from various sources, including Science Direct, Elsevier, NCBI, and Web of Science, are used in this review. In-silico techniques and optimization algorithms can provide versatile solutions in drug discovery ventures. The structure-based drug design technique is widely used to understand chemical constituents' molecular-level interactions and identify hit leads. This review will discuss the concept of CADD, in-silico tools, virtual screening in drug discovery, and the concept of natural products as anticancer therapies. Representative examples of molecules identified will also be provided.

The known unknowns of the Hsp90 chaperone

Molecular chaperones are vital proteins that maintain protein homeostasis by assisting in protein folding, activation, degradation, and stress protection. Among them, heat-shock protein 90 (Hsp90) stands out as an essential proteostasis hub in eukaryotes, chaperoning hundreds of 'clients' (substrates). After decades of research, several 'known unknowns' about the molecular function of Hsp90 remain unanswered, hampering rational drug design for the treatment of cancers, neurodegenerative, and other diseases. We highlight three fundamental open questions, reviewing the current state of the field for each, and discuss new opportunities, including single-molecule technologies, to answer the known unknowns of the Hsp90 chaperone.

Development of a Fluorescence Probe for High-Throughput Screening of Allosteric Inhibitors Targeting TRAP1

Tumor necrosis factor receptor-associated protein 1 (TRAP1) is a molecular chaperone implicated in pro-tumorigenic pathways by regulating the folding of substrate proteins (clients) within cancer cells. Recent research has pinpointed a potentially druggable allosteric site within the client binding site (CBS) of TRAP1, suggesting this site might offer a more effective strategy for developing potent and selective TRAP1 inhibitors. However, the absence of reliable assay systems has hindered quantitative evaluation of inhibitors. In this study, we have developed a fluorescent probe, Rho6TPP, designed to target the CBS. Utilizing fluorescence polarization-based high-throughput screening assays, Rho6TPP exhibits excellent signal-to-noise ratio (>20), Z factor (>0.6), and Z' factor (>0.6). Additionally, it facilitates comparative analysis of existing small molecules and discovery of novel binders. MitoTam, a mitochondria-targeted tamoxifen, emerges as a potent CBS-targeting TRAP1 inhibitor. Our findings highlight the potential of Rho6TPP as a crucial tool for advancing the development of CBS-targeting TRAP1 inhibitors.

GbHSP90 act as a dual functional role regulated in telomere stability in Ginkgo biloba

The heat shock protein 90 (HSP90) family members are not only widely involved in animal cellular immune response and signal transduction pathway regulation, but also play an important role in plant development and environmental stress response. Here,we identified a HSP90 family member in Ginkgo biloba, designated as GbHSP90, which performs a dual functional role to regulate telomere stability. GbHSP90 was screened by a yeast one-hybrid library using the Ginkgo biloba telomeric DNA (TTTAGGG)5. Fluorescence polarization, surface plasmon resonance(SPR) and EMSA technologyies revealed a specific interaction between GbHSP90 and the double-stranded telomeric DNA via its N-CR region, with no affinity for the single-stranded telomeric DNA or human double-stranded telomeric DNA. Furthermore, yeast two-hybrid system and Split-LUC assay demonstrated that GbHSP90 can interacts with two telomere end-binding proteins:the ginkgo telomerase reverse transcriptase (GbTERT) and the ginkgo Structural Maintenance of Chromosomes protein 1 (GbSMC1). Overexpression of GbHSP90 in human 293 T and HeLa cells increased cell growth rate, the content of telomerase reverse transcriptase (TERT), and promote cell division and inhibit cell apoptosis. Our results indicated GbHSP90 have dually functions: as a telomere-binding protein that binds specifically to double-stranded telomeric DNA and as a molecular chaperone that modulates cell differentiation and apoptosis by binding to telomere protein complexes in Ginkgo biloba. This study contributes to a significantly understanding of the unique telomere complex structure and regulatory mechanisms in Ginkgo biloba, a long-lived tree species.

Geldanamycins: Potent Hsp90 Inhibitors with Significant Potential in Cancer Therapy

Geldanamycin, an ansa-macrolide composed of a rigid benzoquinone ring and an aliphatic ansa-bridge, was isolated from Streptomyces hygroscopicus. Geldanamycin is a potent heat shock protein inhibitor with remarkable antiproliferative activity. However, it shows pronounced hepatotoxicity in animal models and unfavorable pharmacokinetic properties. Four geldanamycin analogs have progressed through various phases of clinical trials, but none have yet completed clinical evaluation or received FDA approval. To enhance the efficacy of these Hsp90 inhibitors, strategies such as prodrug approaches or nanocarrier delivery systems could be employed to minimize systemic and organ toxicity. Furthermore, exploring new drug combinations may help overcome resistance, potentially improving therapeutic outcomes. This review discusses the mechanism of action of geldanamycin, its pharmacokinetic properties, and the various approaches employed to alleviate its toxicity and maximize its clinical efficacy. The main focus is on those derivatives that have progressed to clinical trials or that have shown important in vivo activity in preclinical models.

A genetic study to identify pathogenic mechanisms and drug targets for benign prostatic hyperplasia: a multi-omics Mendelian randomization study

Benign prostatic hyperplasia (BPH) as a common geriatric disease in urology, the incidence and prevalence are rapidly increasing with the aging society, prompting an urgent need for effective prevention and treatment of BPH. However, limited therapeutic efficacy and higher risk of complications result in the treatment of BPH remaining challenging. The unclear pathogenic mechanism also hampers further exploration of therapeutic approaches for BPH. In this study, we used multi-omics methods to integrate genomics, transcriptomics, immunomics, and metabolomics data and identify biomolecules associated with BPH. We performed transcriptomic imputation, summary data-based Mendelian randomization (SMR), joint/conditional analysis, colocalization analysis, and FOCUS to explore high-confidence genes associated with BPH in blood and prostate tissue. Subsequently, three-step SMR was used to identify the DNA methylation sites regulating high-confidence genes to improve the pathogenic pathways of BPH. We also used cis-instruments of druggable genes to conduct SMR analysis to find potential drug targets for BPH. Finally, we used MR analysis to explore the immune pathways and metabolomics related to BPH. Multiple analytical methods identified BTN3A2 (Blood: TWAS Z score = 5.02912, TWAS P = 4.93 × 10-7; Prostate: TWAS Z score = 4.89, TWAS P = 1.01 × 10-6) and C4A (Blood: TWAS Z score = 4.90754, TWAS P = 9.22 × 10-7; Prostate: TWAS Z score = 5.084, TWAS P = 3.70 × 10-7) as high-confidence genes for BPH and identified the cg14345882-BTN3A2-BPH pathogenic pathway. We also used druggable gene data to identify 30 promising therapeutic target genes, including BTN3A2 and C4A. For MR analysis of immune pathways, we identified immune cell surface molecules as well as the inflammatory factor IL-17 (OR = 1.25, 95% CI = 1.09-1.43, PFDR = 0.12, Maximum likelihood) as risk factors for BPH. In addition, we found that disulfide levels of cysteinylglycine (OR = 1.11, 95% CI = 1.05-1.18, P = 5.18 × 10-4, Weighted median), oxidation levels of cysteinylglycine (OR = 1.09, 95% CI = 1.04-1.14, P = 3.87 × 10-4, Weighted median), and sebacate levels (OR = 1.05, 95% CI = 1.02-1.08, P = 3.0 × 10-4, Maximum likelihood) increase the risk of BPH. This multi-omics study explored biomolecules associated with BPH, improved the pathogenic pathways of BPH, and identified promising therapeutic targets. Our results provide evidence for future studies aimed at developing appropriate therapeutic interventions.

Vitamin C as a functional enhancer in the non-specific immune defense, antioxidant capacity and resistance to low-temperature stress of juvenile mud crab, Scylla paramamosain

This experiment was conducted to explore the effects of dietary vitamin C supplementation on non-specific immune defense, antioxidant capacity and resistance to low-temperature stress of juvenile mud crab (Scylla paramamosain). Mud crabs with an initial weight of 14.67 ± 0.13 g were randomly divided into 6 treatments and fed diets with 0.86 (control), 44.79, 98.45, 133.94, 186.36 and 364.28 mg/kg vitamin C, respectively. The experiment consisted of 6 treatments, each treatment was designed with 4 replicates and each replicate was stocked with 8 crabs. After 42 days of feeding experiment, 2 crabs were randomly selected from each replicate, and a total of 8 crabs in each treatment were carried out 72 h low-temperature challenge experiment. The results showed that crabs fed diets with 186.36 and 364.28 mg/kg vitamin C significantly improved the activities of alkaline phosphatase (AKP) and acid phosphatase (ACP) in hemolymph and hepatopancreas (P < 0.05). Crabs fed diet with 133.94 mg/kg vitamin C significantly decreased the concentration of nitric oxide (NO) and the activity of nitric oxide synthase (NOS) in hemolymph (P < 0.05). Diet with 133.94 mg/kg vitamin C was improved the activity of polyphenol oxidase (PPO) and the concentration of albumin (ALB) in hemolymph. Crabs fed diet with 133.94 mg/kg vitamin C showed lower concentration of malondialdehyde (MDA) in hemolymph and hepatopancreas than those fed the other diets. Meanwhile, crabs fed diet with 98.45 mg/kg vitamin C showed higher activity of total superoxide dismutase (T-SOD) in hemolymph, and crabs fed diet with 133.94 mg/kg vitamin C showed higher activity of T-SOD in hepatopancreas. Crabs fed diet with 186.36 mg/kg vitamin C significantly decreased the concentration of reduced glutathione (GSH) and the activity of glutathione peroxidase (GSH-PX) in hepatopancreas (P < 0.05). In normal temperature, crabs fed diets with 133.94 mg/kg vitamin C significantly up-regulated the expression levels of gpx (glutathione peroxidase) and trx (thioredoxin) in hepatopancreas compared with the control treatment (P < 0.05). The highest expression levels of relish, il16 (interleukin 16), caspase 2 (caspase 2), p38 mapk (p38 mitogen-activated protein kinases) and bax (bcl-2 associated x protein) in hepatopancreas were found at crabs fed control diet (P < 0.05). Moreover, crabs fed diet with 133.94 mg/kg vitamin C showed higher expression levels of alf-3 (anti-lipopolysaccharide factor 3) and bcl-2 (B-cell lymphoma 2) in hepatopancreas than those fed the other diets (P < 0.05). Under low-temperature stress, crabs fed diet with 133.94 mg/kg vitamin C significantly improved the expression levels of hsp90 (heat shock protein 90), cat (catalase), gpx, prx (thioredoxin peroxidase) and trx in hepatopancreas (P < 0.05). In addition, dietary with 133.94 vitamin C significantly up-regulated the expression levels of alf-3 and bcl-2 (P < 0.05). Based on two slope broken-line regression analysis of activity of PPO against the dietary vitamin C level, the optimal dietary vitamin C requirement was estimated to be 144.81 mg/kg for juvenile mud crab. In conclusion, dietary 133.94-144.81 mg/kg vitamin C significantly improved the non-specific immune defense, antioxidant capacity and resistance to low-temperature stress of juvenile mud crab.

Unraveling the mysteries of chicken proteomics: Insights into follicle development and reproduction

Chicken proteomics is a valuable method for comprehending the many mechanisms involved in follicle growth and reproduction in birds. This study offers a thorough summary of the latest progress in chicken proteomics research, specifically highlighting the knowledge obtained regarding follicle development and reproductive physiology. Proteomic studies have revealed essential proteins and pathways that play a role in follicle development, including those that control oocyte size, maturation, and ovulation. Proteomic investigations have provided insight into the molecular pathways that govern reproductive processes. By utilizing advanced proteomic technologies, including mass spectrometry and protein microarray analysis, we have been able to identify and measure many proteins in chicken follicles at their different developmental stages. The utilization of proteomic methods has enabled the identification of previously unknown biomarkers for reproductive efficiency that expedited the creation of innovative diagnostic instruments for monitoring reproductive health in chicken. Chicken proteomics not only offers insights into follicle growth and reproduction but also uncovers the effects of environmental influences on reproductive function. This provides new opportunities for exploring the molecular pathways that cause these effects. The integration of current data with upcoming proteomic technologies offers the potential for innovative strategies to enhance chicken reproduction.

AA, Abu Elgasim MAE, Almansour ZH, Elesawy BH, Elmorsy EA. STA-9090 in combination with a statin exerts enhanced protective effects in rats fed a high-fat diet and exposed to diethylnitrosamine and thioacetamide

Introduction

Liver fibrosis is a significant global health burden that lacks effective therapies. It can progress to cirrhosis and hepatocellular carcinoma (HCC). Aberrant hedgehog pathway activation is a key driver of fibrogenesis and cancer, making hedgehog inhibitors potential antifibrotic and anticancer agents.

Methods

We evaluated simvastatin and STA-9090, alone and combined, in rats fed a high-fat diet (HFD) and exposed to diethylnitrosamine and thioacetamide (DENA/TAA). Simvastatin inhibits HMG-CoA reductase, depleting cellular cholesterol required for Sonic hedgehog (Shh) modification and signaling. STA-9090 directly inhibits HSP90 chaperone interactions essential for Shh function. We hypothesized combining these drugs may provide liver protective effects through complementary targeting of the hedgehog pathway. Endpoints assessed included liver function tests, oxidative stress markers, histopathology, extracellular matrix proteins, inflammatory cytokines, and hedgehog signaling components.

Results

HFD and DENA/TAA caused aberrant hedgehog activation, contributing to fibrotic alterations with elevated liver enzymes, oxidative stress, dyslipidemia, inflammation, and collagen deposition. Monotherapies with simvastatin or STA-9090 improved these parameters, while the combination treatment provided further enhancements, including improved survival, near-normal liver histology, and compelling hedgehog pathway suppression.

Discussion

Our findings demonstrate the enhanced protective potential of combined HMG CoA reductase and HSP90 inhibition in rats fed a HFD and exposed to DENA and TAA. This preclinical study could help translate hedgehog-targeted therapies to clinical evaluation for treating this major unmet need.

In Silico Analysis: Molecular Characterization and Evolutionary Study of CLCN Gene Family in Buffalo

Chloride channels (ClCs) have received global interest due to their significant role in the regulation of ion homeostasis, fluid transport, and electrical excitability of tissues and organs in different mammals and contributing to various functions, such as neuronal signaling, muscle contraction, and regulating the electrolytes' balance in kidneys and other organs. In order to define the chloride voltage-gated channel (CLCN) gene family in buffalo, this study used in silico analyses to examine physicochemical properties, evolutionary patterns, and genome-wide identification. We identified eight CLCN genes in buffalo. The ProtParam tool analysis identified a number of important physicochemical properties of these proteins, including hydrophilicity, thermostability, in vitro instability, and basic nature. Based on their evolutionary relationships, a phylogenetic analysis divided the eight discovered genes into three subfamilies. Furthermore, a gene structure analysis, motif patterns, and conserved domains using TBtool demonstrated the significant conservation of this gene family among selected species over the course of evolution. A comparative amino acid analysis using ClustalW revealed similarities and differences between buffalo and cattle CLCN proteins. Three duplicated gene pairs were identified, all of which were segmental duplications except for CLCN4-CLCN5, which was a tandem duplication in buffalo. For each gene pair, the Ka/Ks test ratio findings showed that none of the ratios was more than one, indicating that these proteins were likely subject to positive selection. A synteny analysis confirmed a conserved pattern of genomic blocks between buffalo and cattle. Transcriptional control in cells relies on the binding of transcription factors to specific sites in the genome. The number of transcription factor binding sites (TFBSs) was higher in cattle compared to buffalo. Five main recombination breakpoints were identified at various places in the recombination analysis. The outcomes of our study provide new knowledge about the CLCN gene family in buffalo and open the door for further research on candidate genes in vertebrates through genome-wide studies.

HSP90 multi-functionality in cancer

The 90-kDa heat shock proteins (HSP90s) are molecular chaperones essential for folding, unfolding, degradation and activity of a wide range of client proteins. HSP90s and their cognate co-chaperones are subject to various post-translational modifications, functional consequences of which are not fully understood in cancer. Intracellular and extracellular HSP90 family members (HSP90α, HSP90β, GRP94 and TRAP1) promote cancer by sustaining various hallmarks of cancer, including cell death resistance, replicative immortality, tumor immunity, angiogenesis, invasion and metastasis. Given the importance of HSP90 in tumor progression, various inhibitors and HSP90-based vaccines were developed for the treatment of cancer. Further understanding of HSP90 functions in cancer may provide new opportunities and novel therapeutic strategies for the treatment of cancer.

An update on the status of HSP90 inhibitors in cancer clinical trials

The evolutionary conserved molecular chaperone heat shock protein 90 (HSP90) plays an indispensable role in tumorigenesis by stabilizing client oncoproteins. Although the functionality of HSP90 is tightly regulated, cancer cells exhibit a unique dependence on this chaperone, leading to its overexpression, which has been associated with poor prognosis in certain malignancies. While various strategies targeting heat shock proteins (HSPs) involved in carcinogenesis have been explored, only inhibition of HSP90 has consistently and effectively resulted in proteasomal degradation of its client proteins. To date, a total of 22 HSP90 inhibitors (HSP90i) have been tested in 186 cancer clinical trials, as reported by clinicaltrials.gov. Among these trials, 60 % have been completed, 10 % are currently active, and 30 % have been suspended, terminated, or withdrawn. HSP90 inhibitors (HSP90i) have been used as single agents or in combination with other drugs for the treatment of various cancer types in clinical trials. Notably, improved clinical outcomes have been observed when HSP90i are used in combination therapies, as they exhibit a synergistic antitumor effect. However, as single agents, HSP90i have shown limited clinical activity due to drug-related toxicity or therapy resistance. Recently, active trials conducted in Japan evaluating TAS-116 (pimitespib) have demonstrated promising results with low toxicity as monotherapy and in combination with the immune checkpoint inhibitor nivolumab. Exploratory biomarker analyses performed in various trials have demonstrated target engagement that suggests the potential for identifying patient populations that may respond favorably to the therapy. In this review, we discuss the advances made in the past 5 years regarding HSP90i and their implications in anticancer therapeutics. Our focus lies in evaluating drug efficacy, prognosis forecast, pharmacodynamic biomarkers, and clinical outcomes reported in published trials. Through this comprehensive review, we aim to shed light on the progress and potential of HSP90i as promising therapeutic agents in cancer treatment.

Identifying autophagy-related mRNAs and potential ceRNA networks in meniscus degeneration based on RNA sequencing and experimental validation

Purpose

The intimate connection between long noncoding RNA (lncRNA) and autophagy has been established in cartilage degeneration. However, their roles in meniscal degeneration remain ambiguous. This study aimed to identify the key autophagy-related lncRNA and its associated regulatory network in meniscal degeneration in the context of osteoarthritis (OA).

Methods

RNA sequencing was performed to identify differentially expressed lncRNAs (DELs) and mRNAs (DEMs), which were then conducted to enrichment analyses using the DAVID database and Metascape. Autophagy-related DEMs were identified by combining DEMs with data from the Human Autophagy Database. Three databases were used to predict miRNA, and the DIANA LncBase Predicted database was utilized to predict miRNA-lncRNA interactions. Based on these predictions, comprehensive competitive endogenous RNA (ceRNA) network were constructed. The expression levels of the classical autophagy markers and autophagy-related ceRNA network were validated. Additionally, Gene Set Enrichment Analysis (GSEA) was performed using autophagy-related DEMs.

Results

310 DELs and 320 DEMs were identified, with five upregulated and one downregulated autophagy-related DEMs. Through reverse prediction of miRNA, paired miRNA-lncRNA interactions, and verification using RT-qPCR, two lncRNAs (PCAT19, CLIP1-AS1), two miRNA (has-miR-3680-3p and has-miR-4795-3p) and two mRNAs (BAG3 and HSP90AB1) were included in the constructed ceRNA regulatory networks. GSEA indicated that the increased expression of autophagy-related mRNAs inhibited glycosaminoglycan biosynthesis in the degenerative meniscus.

Conclusion

This study presented the first construction of regulatory ceRNA network involving autophagy-related lncRNA-miRNA-mRNA interactions in OA meniscus. These findings offered valuable insights into the mechanisms underlying meniscal degeneration and provided potential targets for therapeutic intervention.

Current biomarkers and treatment strategies in Alzheimer disease: An overview and future perspectives

Alzheimer's disease (AD), a progressive degenerative disorder first identified by Alois Alzheimer in 1907, poses a significant public health challenge. Despite its prevalence and impact, there is currently no definitive ante mortem diagnosis for AD pathogenesis. By 2050, the United States may face a staggering 13.8 million AD patients. This review provides a concise summary of current AD biomarkers, available treatments, and potential future therapeutic approaches. The review begins by outlining existing drug targets and mechanisms in AD, along with a discussion of current treatment options. We explore various approaches targeting Amyloid β (Aβ), Tau Protein aggregation, Tau Kinases, Glycogen Synthase kinase-3β, CDK-5 inhibitors, Heat Shock Proteins (HSP), oxidative stress, inflammation, metals, Apolipoprotein E (ApoE) modulators, and Notch signaling. Additionally, we examine the historical use of Estradiol (E2) as an AD therapy, as well as the outcomes of Randomized Controlled Trials (RCTs) that evaluated antioxidants (e.g., vitamin E) and omega-3 polyunsaturated fatty acids as alternative treatment options. Notably, positive effects of docosahexaenoic acid nutriment in older adults with cognitive impairment or AD are highlighted. Furthermore, this review offers insights into ongoing clinical trials and potential therapies, shedding light on the dynamic research landscape in AD treatment.

Immunohistochemical localization and expression of heat shock proteins (HSP27, HSP60, HSP70, and HSP90) during the oestrous cycle, pregnancy, and lactation in rat ovaries

This study aimed to determine the expressions of HSP27, HSP60, HSP70, and HSP90 in rat ovaries during the oestrous cycle, pregnancy, and lactation. In follicle cells, HSP27 and HSP70 expression was not observed. HSP60 in oocytes was higher in the early stages of follicular development but decreased and disappeared as the follicle grew. HSP60 in granulosa and theca cells increased with follicle development and decreased with atresia. HSP90 in follicle cells did not change during follicle development or atresia. The expression of HSPs in interstitial cells was higher in the proestrus and estrus phases of the estrous cycle. The expression of HSPs in these cells was higher on day 5 of pregnancy, decreased on day 10, and decreased further on days 15 and 20. The expression of HSPs, which decreased in the second half of pregnancy, increased again on the first day of lactation. The expression of HSPs then decreased on day 5 of lactation and further decreased on days 10 and 20. HSP60 and HSP90 were positive in new and old corpus luteums (CLs) and their expression did not change during luteal development or regression. HSP27 and HSP70 were absent in new CLs. HSP27 was positive in old CLs and showed the same staining pattern during luteal regression. HSP70 expression was determined in old cyclic CLs during the oestrous cycle and pregnancy and decreased with luteal regression. HSP70 expression in old pregnancy CLs during lactation was very weak compared to the oestrous cycle and pregnancy. In conclusion, HSP60 and HSP90 may participate in folliculogenesis, luteal development, and steroidogenesis in luteal cells, and HSP27, HSP60, HSP70, and HSP90 may be effective in luteal regression and steroidogenesis in interstitial cells. HSP27 and HSP70 may be used as markers to identify old CLs in rats.

An epigenetic change in a moth is generated by temperature and transmitted to many subsequent generations mediated by RNA

Epigenetic changes in sexually reproducing animals may be transmitted usually only through a few generations. Here we discovered a case where epigenetic change lasts 40 generations. This epigenetic phenomenon occurs in the short antennae (sa) mutation of the flour moth (Ephestia kuehniella). We demonstrate that is probably determined by a small RNA (e.g., piRNA, miRNA, tsRNA) and transmitted in this way to subsequent generations through the male and female gametes. The observed epigenetic change cancels sa mutation and creates a wild phenotype (a moth that appears to have no mutation). It persists for many generations (40 recorded). This epigenetic transgenerational effect (suppression homozygous mutation for short antennae) in the flour moth is induced by changes during ontogenetic development, such as increased temperature on pupae development, food, different salts in food, or injection of RNA from the sperm of already affected individuals into the eggs. The epigenetic effect may occasionally disappear in some individuals and/or progeny of a pair in the generation chain in which the effect transfers. We consider that the survival of RNA over many generations has adaptive consequences. It is mainly a response to environmental change that is transmitted to offspring via RNA. In this study, we test an interesting epigenetic effect with an unexpected length after 40 generations and test what is its cause. Such transfer of RNA to subsequent generations may have a greater evolutionary significance than previously thought. Based on some analogies, we also discuss of the connection with the SIR2 gene.

Genome-Wide Analysis of the Oat (Avena sativa) HSP90 Gene Family Reveals Its Identification, Evolution, and Response to Abiotic Stress

Oats (Avena sativa) are an important cereal crop and cool-season forage worldwide. Heat shock protein 90 (HSP90) is a protein ubiquitously expressed in response to heat stress in almost all plants. To date, the HSP90 gene family has not been comprehensively reported in oats. Herein, we have identified twenty HSP90 genes in oats and elucidated their evolutionary pathways and responses to five abiotic stresses. The gene structure and motif analyses demonstrated consistency across the phylogenetic tree branches, and the groups exhibited relative structural conservation. Additionally, we identified ten pairs of segmentally duplicated genes in oats. Interspecies synteny analysis and orthologous gene identification indicated that oats share a significant number of orthologous genes with their ancestral species; this implies that the expansion of the oat HSP90 gene family may have occurred through oat polyploidization and large fragment duplication. The analysis of cis-acting elements revealed their influential role in the expression pattern of HSP90 genes under abiotic stresses. Analysis of oat gene expression under high-temperature, salt, cadmium (Cd), polyethylene glycol (PEG), and abscisic acid (ABA) stresses demonstrated that most AsHSP90 genes were significantly up-regulated by heat stress, particularly AsHSP90-7, AsHSP90-8, and AsHSP90-9. This study offers new insights into the amplification and evolutionary processes of the AsHSP90 protein, as well as its potential role in response to abiotic stresses. Furthermore, it lays the groundwork for understanding oat adaptation to abiotic stress, contributing to research and applications in plant breeding.

Heat-shock protein 90 alleviates oxidative stress and reduces apoptosis in liver of Seriola aureovittata (yellowtail kingfish) under high-temperature stress

Hsp90s are molecular chaperones that enhance fish tolerance to high-temperature stress. However, the function of Hsp90s in Seriola aureovittata (yellowtail kingfish) under high-temperature stress remains largely unknown. Here, two Hsp90 isoforms were identified in S. aureovittata by bioinformatics analysis: SaHsp90α and SaHsp90β. The coding sequence of SaHsp90α was 2193-bp long and encoded a polypeptide of 730 amino acids; SaHsp90β was 2178-bp long and encoded a polypeptide of 725 amino acids. SaHsp90α and SaHsp90β both contained a HATPase domain and a HSP90 domain. Their transcripts were detected in all examined S. aureovittata tissues, with relatively high levels in the gonads, head kidney, and intestine. During high-temperature stress at 28 °C, the expression levels of SaHsp90α and SaHsp90β transcripts were significantly increased in liver. After simultaneously knocking down the expression of the SaHsp90s, there was a significant decrease in liver superoxide dismutase (SOD) activity and a remarkable increase of malondialdehyde content in liver after high-temperature stress. The expression levels of the key caspase family genes caspase-3 and caspase-7 were also significantly upregulated by high-temperature stress in SaHsp90-knockdown liver. TUNEL labeling demonstrated that the number of apoptotic cells significantly increased in the SaHsp90-knockdown group when high-temperature treatment lasted for 48 h. Protein-protein docking analysis predicted that SaHsp90α and SaHsp90β can bind to S. aureovittata SOD and survivin, which are key proteins for maintenance of redox homeostasis and inhibition of apoptosis. These findings demonstrate that SaHsp90α and SaHsp90β play a crucial role in resistance to high-temperature stress by regulating redox homeostasis and apoptosis in yellowtail kingfish.

Heat shock protein 90: biological functions, diseases, and therapeutic targets

Heat shock protein 90 (Hsp90) is a predominant member among Heat shock proteins (HSPs), playing a central role in cellular protection and maintenance by aiding in the folding, stabilization, and modification of diverse protein substrates. It collaborates with various co-chaperones to manage ATPase-driven conformational changes in its dimer during client protein processing. Hsp90 is critical in cellular function, supporting the proper operation of numerous proteins, many of which are linked to diseases such as cancer, Alzheimer's, neurodegenerative conditions, and infectious diseases. Recognizing the significance of these client proteins across diverse diseases, there is a growing interest in targeting Hsp90 and its co-chaperones for potential therapeutic strategies. This review described biological background of HSPs and the structural characteristics of HSP90. Additionally, it discusses the regulatory role of heat shock factor-1 (HSF-1) in modulating HSP90 and sheds light on the dynamic chaperone cycle of HSP90. Furthermore, the review discusses the specific contributions of HSP90 in various disease contexts, especially in cancer. It also summarizes HSP90 inhibitors for cancer treatment, offering a thoughtful analysis of their strengths and limitations. These advancements in research expand our understanding of HSP90 and open up new avenues for considering HSP90 as a promising target for therapeutic intervention in a range of diseases.

Upregulation of TaHSP90A transcripts enhances heat tolerance and increases grain yield in wheat under changing climate conditions

Plants have certain adaptation mechanisms to combat temperature extremes and fluctuations. The heat shock protein (HSP90A) plays a crucial role in plant defence mechanisms under heat stress. In silico analysis of the eight TaHSP90A transcripts showed diverse structural patterns in terms of intron/exons, domains, motifs and cis elements in the promoter region in wheat. These regions contained cis elements related to hormones, biotic and abiotic stress and development. To validate these findings, two contrasting wheat genotypes E-01 (thermo-tolerant) and SHP-52 (thermo-sensitive) were used to evaluate the expression pattern of three transcripts TraesCS2A02G033700.1, TraesCS5B02G258900.3 and TraesCS5D02G268000.2 in five different tissues at five different temperature regimes. Expression of TraesCS2A02G033700.1 was upregulated (2-fold) in flag leaf tissue after 1 and 4h of heat treatment in E-01. In contrast, SHP-52 showed downregulated expression after 1h of heat treatment. Additionally, it was shown that under heat stress, the increased expression of TaHSP90A led to an increase in grain production. As the molecular mechanism of genes involved in heat tolerance at the reproductive stage is mostly unknown, these results provide new insights into the role of TaHSP90A transcripts in developing phenotypic plasticity in wheat to develop heat-tolerant cultivars under the current changing climate scenario.

Ligand-Based Competition Binding by Real-Time 19F NMR in Human Cells

The development of more effective drugs requires knowledge of their bioavailability and binding efficacy directly in the native cellular environment. In-cell nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for investigating ligand-target interactions directly in living cells. However, the target molecule may be NMR-invisible due to interactions with cellular components, while observing the ligand by 1H NMR is impractical due to the cellular background. Such limitations can be overcome by observing fluorinated ligands by 19F in-cell NMR as they bind to the intracellular target. Here we report a novel approach based on real-time in-cell 19F NMR that allows measuring ligand binding affinities in human cells by competition binding, using a fluorinated compound as a reference. The binding of a set of compounds toward Hsp90α was investigated. In principle, this approach could be applied to other pharmacologically relevant targets, thus aiding the design of more effective compounds in the early stages of drug development.

Update on Combination Strategies of PARP Inhibitors

The application of PARP inhibitors has revolutionized cancer treatment and has achieved significant advancements, particularly with regard to tumors with defects in genes involved in homologous recombination repair (HRR) processes, such as BRCA1 and BRCA2. Despite the promising outcomes of PARP inhibitors, certain limitations and challenges still exist, including acquired drug resistance, severe side effects, and limited therapeutic benefits for patients without homologous recombination deficiency (HRD). Various combinations involving PARP inhibitors have been developed to overcome these limitations. Among these, combinations with immune checkpoint inhibitors, antiangiogenic agents, and various small-molecule inhibitors are well-studied strategies that show great potential for optimizing the efficacy of PARP inhibitors, overcoming resistance mechanisms, and expanding target populations. However, the efficiency and overlapping toxicity of these combination strategies for cancers vary among studies, thereby limiting their use. In this review, we describe the mechanisms and limitations of PARP inhibitors to better understand the mechanisms of combination treatments. Furthermore, we have summarized recent studies on the combination of PARP inhibitors with a range of medications and discussed their clinical efficacy. The objective of this review is to enhance the comprehensiveness of information pertaining to this topic.

The multi-faceted roles of R2TP complex span across regulation of gene expression, translation, and protein functional assembly

Macromolecular complexes play essential roles in various cellular processes. The assembly of macromolecular assemblies within the cell must overcome barriers imposed by a crowded cellular environment which is characterized by an estimated concentration of biological macromolecules amounting to 100-450 g/L that take up approximately 5-40% of the cytoplasmic volume. The formation of the macromolecular assemblies is facilitated by molecular chaperones in cooperation with their co-chaperones. The R2TP protein complex has emerged as a co-chaperone of Hsp90 that plays an important role in macromolecular assembly. The R2TP complex is composed of a heterodimer of RPAP3:P1H1DI that is in turn complexed to members of the ATPase associated with diverse cellular activities (AAA +), RUVBL1 and RUVBL2 (R1 and R2) families. What makes the R2TP co-chaperone complex particularly important is that it is involved in a wide variety of cellular processes including gene expression, translation, co-translational complex assembly, and posttranslational protein complex formation. The functional versatility of the R2TP co-chaperone complex makes it central to cellular development; hence, it is implicated in various human diseases. In addition, their roles in the development of infectious disease agents has become of interest. In the current review, we discuss the roles of these proteins as co-chaperones regulating Hsp90 and its partnership with Hsp70. Furthermore, we highlight the structure-function features of the individual proteins within the R2TP complex and describe their roles in various cellular processes.

Understanding fluconazole tolerance in Candida albicans: implications for effective treatment of candidiasis and combating invasive fungal infections

OBJECTIVES

Fluconazole (FLC) tolerant phenotypes in Candida species contribute to persistent candidemia and the emergence of FLC resistance. Therefore, making FLC fungicidal and eliminating FLC tolerance are important for treating invasive fungal diseases (IFDs) caused by Candida species. However, the mechanisms of FLC tolerance in Candida species remain to be fully explored.

METHODS

This review discusses the high incidence of FLC tolerance in Candida species and the importance of successfully clearing FLC tolerance in treating candidiasis. We further define and characterize FLC tolerance in C. albicans.

RESULTS

This review identifies global factors affecting FLC tolerance and suggest that FLC tolerance is a strategy of C. albicans response to FLC damage whose mechanism differs from FLC resistance.

CONCLUSIONS

This review highlights the significance of the cell membrane and cell wall integrity in FLC tolerance, guiding approaches to combat IFDs caused by Candida species..

The development of cancers research based on mitochondrial heat shock protein 90

Mitochondrial heat shock protein 90 (mtHsp90), including Tumor necrosis factor receptor-associated protein 1 (TRAP1) and Hsp90 translocated from cytoplasm, modulating cellular metabolism and signaling pathways by altering the conformation, activity, and stability of numerous client proteins, and is highly expressed in tumors. mtHsp90 inhibition results in the destabilization and eventual degradation of its client proteins, leading to interference with various tumor-related pathways and efficient control of cancer cell development. Among these compounds, gamitrinib, a specific mtHsp90 inhibitor, has demonstrated its safety and efficacy in several preclinical investigations and is currently undergoing evaluation in clinical trials. This review aims to provide a comprehensive overview of the present knowledge pertaining to mtHsp90, encompassing its structure and function. Moreover, our main emphasis is on the development of mtHsp90 inhibitors for various cancer therapies, to present a thorough overview of the recent pre-clinical and clinical advancements in this field.

Functionally comparable but evolutionarily distinct nucleotide-targeting effectors help identify conserved paradigms across diverse immune systems

While nucleic acid-targeting effectors are known to be central to biological conflicts and anti-selfish element immunity, recent findings have revealed immune effectors that target their building blocks and the cellular energy currency-free nucleotides. Through comparative genomics and sequence-structure analysis, we identified several distinct effector domains, which we named Calcineurin-CE, HD-CE, and PRTase-CE. These domains, along with specific versions of the ParB and MazG domains, are widely present in diverse prokaryotic immune systems and are predicted to degrade nucleotides by targeting phosphate or glycosidic linkages. Our findings unveil multiple potential immune systems associated with at least 17 different functional themes featuring these effectors. Some of these systems sense modified DNA/nucleotides from phages or operate downstream of novel enzymes generating signaling nucleotides. We also uncovered a class of systems utilizing HSP90- and HSP70-related modules as analogs of STAND and GTPase domains that are coupled to these nucleotide-targeting- or proteolysis-induced complex-forming effectors. While widespread in bacteria, only a limited subset of nucleotide-targeting effectors was integrated into eukaryotic immune systems, suggesting barriers to interoperability across subcellular contexts. This work establishes nucleotide-degrading effectors as an emerging immune paradigm and traces their origins back to homologous domains in housekeeping systems.

Protection against Aβ-induced neuronal damage by KU-32: PDHK1 inhibition as important target

A feature of most neurodegenerative diseases is the presence of "mis-folded proteins" that form aggregates, suggesting suboptimal activity of neuronal molecular chaperones. Heat shock protein 90 (Hsp90) is the master regulator of cell responses to "proteotoxic" stresses. Some Hsp90 modulators activate cascades leading to upregulation of additional chaperones. Novobiocin is a modulator at the C-terminal ATP-binding site of Hsp90. Of several novobiocin analogs synthesized and tested for protection against amyloid beta (Aβ)-induced neuronal death, "KU-32" was the most potent in protecting primary neurons, but did not increase expression of other chaperones believed to help clear misfolded proteins. However, KU-32 reversed Aβ-induced superoxide formation, activated Complex I of the electron transfer chain in mitochondria, and blocked the Aβ-induced inhibition of Complex I in neuroblastoma cells. A mechanism for these effects of KU-32 on mitochondrial metabolism appeared to be the inhibition of pyruvate dehydrogenase kinase (PDHK), both in isolated brain mitochondria and in SH-SY5Y cells. PDHK inhibition by the classic enzyme inhibitor, dichloroacetate, led to neuroprotection from Aβ25-35-induced cell injury similarly to KU-32. Inhibition of PDHK in neurons would lead to activation of the PDH complex, increased acetyl-CoA generation, stimulation of the tricarboxylic acid cycle and Complex I in the electron transfer chain, and enhanced oxidative phosphorylation. A focus of future studies may be on the potential value of PDHK as a target in AD therapy.

Simulation of the ligand-leaving process of the human heat shock protein

The human heat shock protein plays a critical role in various diseases and is an important target for pharmacological modulation. Simulation of conformational changes and free energy profiles of the human heat shock protein derived by the ligand-leaving process is a challenging issue. In this work, steered molecular dynamics simulation was adopted to simulate the ligand-leaving process. Two composite systems of heat shock protein NHSP90 and small molecules 6FJ and 6G7 are selected as research objects. The free energy during the leaving of ligand small molecules is calculated using conventional molecular dynamics simulation, steered molecular dynamics simulation (SMD), and the umbrella sampling method. We found that the a slower pulling velocity (0.001 nm ns-1) will result in 2.19 kcal mol-1, and the umbrella sampling method gives a value of 3.26 kcal mol-1 for the free energy difference for the two systems, which reasonably agrees with experimental results. A faster-pulling velocity (0.01 nm ns-1) leads to a large overestimation of free energy. At the same time, the conformational analysis indicated that the faster pulling velocity may lead to the conformational change of NHSP90, which was proved to be false by the slower pulling velocity and the umbrella sampling method.

Neoantigen identification: Technological advances and challenges

Neoantigens have emerged as promising targets for cutting-edge immunotherapies, such as cancer vaccines and adoptive cell therapy. These neoantigens are unique to tumors and arise exclusively from somatic mutations or non-genomic aberrations in tumor proteins. They encompass a wide range of alterations, including genomic mutations, post-transcriptomic variants, and viral oncoproteins. With the advancements in technology, the identification of immunogenic neoantigens has seen rapid progress, raising new opportunities for enhancing their clinical significance. Prediction of neoantigens necessitates the acquisition of high-quality samples and sequencing data, followed by mutation calling. Subsequently, the pipeline involves integrating various tools that can predict the expression, processing, binding, and recognition potential of neoantigens. However, the continuous improvement of computational tools is constrained by the availability of datasets which contain validated immunogenic neoantigens. This review article aims to provide a comprehensive summary of the current knowledge as well as limitations in neoantigen prediction and validation. Additionally, it delves into the origin and biological role of neoantigens, offering a deeper understanding of their significance in the field of cancer immunotherapy. This article thus seeks to contribute to the ongoing efforts to harness neoantigens as powerful weapons in the fight against cancer.

Human Aha1's N-terminal extension confers it holdase activity in vitro

Molecular chaperones are key components of protein quality control system, which plays an essential role in controlling protein homeostasis. Aha1 has been identified as a co-chaperone of Hsp90 known to strongly accelerate Hsp90's ATPase activity. Meanwhile, it is reported that Aha1 could also act as an autonomous chaperone and protect stressed or disordered proteins from aggregation. Here, in this article, a series of in vitro experiments were conducted to verify whether Aha1 has a non-Hsp90-dependent holdase activity and to elucidate the associated molecular mechanism for substrate recognition. According to the results of the refolding assay, the highly conserved N-terminal extension spanning M1 to R16 in Aha1 from higher eukaryotes is responsible for the holdase activity of the protein. As revealed by the NMR data, Aha1's N-terminal extension mainly adopts a disordered conformation in solution and shows no tight contacts with the core structure of Aha1's N-terminal domain. Based on the intrinsically disordered structure feature and the primary sequence of Aha1's N-terminal extension, the fuzzy-type protein-protein interactions involving this specific region and the unfolded substrate proteins are expected. The following mutation analysis data demonstrated that the Van der Waals contacts potentially involving two tryptophans including W4 and W11 do not play a dominant role in the interaction between Aha1 and unfolded maltose binding protein (MBP). Meanwhile, since the high concentration of NaCl could abolish the holdase activity of Aha1, the electrostatic interactions mediated by those charged residues in Aha1's N-terminal extension are thus indicated to play a crucial role in the substrate recognition.

Metal Messengers: Communication in the Bacterial World through Transition-Metal-Sensing Two-Component Systems

Bacteria survive in highly dynamic and complex environments due, in part, to the presence of systems that allow the rapid control of gene expression in the presence of changing environmental stimuli. The crosstalk between intra- and extracellular bacterial environments is often facilitated by two-component signal transduction systems that are typically composed of a transmembrane histidine kinase and a cytosolic response regulator. Sensor histidine kinases and response regulators work in tandem with their modular domains containing highly conserved structural features to control a diverse array of genes that respond to changing environments. Bacterial two-component systems are widespread and play crucial roles in many important processes, such as motility, virulence, chemotaxis, and even transition metal homeostasis. Transition metals are essential for normal prokaryotic physiological processes, and the presence of these metal ions may also influence pathogenic virulence if their levels are appropriately controlled. To do so, bacteria use transition-metal-sensing two-component systems that bind and respond to rapid fluctuations in extracytosolic concentrations of transition metals. This perspective summarizes the structural and metal-binding features of bacterial transition-metal-sensing two-component systems and places a special emphasis on understanding how these systems are used by pathogens to establish infection in host cells and how these systems may be targeted for future therapeutic developments.

QHRD106 ameliorates ischemic stroke injury as a long-acting tissue kallikrein preparation

Ischemic stroke is the second leading cause of death worldwide, and there are limited effective treatment strategies. QHRD106, a polyethyleneglycol (PEG)-modified long-acting tissue kallikrein preparation, has not been reported previously. In this study, we aimed to investigate the therapeutic effect of QHRD106 in ischemic stroke and its possible mechanism. We found that QHRD106 treatment alleviated brain injury after stroke via bradykinin (BK) receptor B2 (B2R) instead of BK receptor B1 (B1R). Mechanistically, QHRD106 reduced high-mobility group box 1 (HMGB1)-induced apoptosis and inflammation after ischemic stroke in vivo and in vitro. Moreover, we confirmed that QHRD106 reduced the level of acetylated HMGB1 and reduced the binding between heat shock protein 90 alpha family class A member 1 (HSP90AA1) and HMGB1, thus inhibiting the translocation and release of HMGB1. In summary, these findings indicate that QHRD106 treatment has therapeutic potential for cerebral ischemic stroke.

The roles of molecular chaperones in regulating cell metabolism

Fluctuations in nutrient and biomass availability, often as a result of disease, impart metabolic challenges that must be overcome in order to sustain cell survival and promote proliferation. Cells adapt to these environmental changes and stresses by adjusting their metabolic networks through a series of regulatory mechanisms. Our understanding of these rewiring events has largely been focused on those genetic transformations that alter protein expression and the biochemical mechanisms that change protein behavior, such as post-translational modifications and metabolite-based allosteric modulators. Mounting evidence suggests that a class of proteome surveillance proteins called molecular chaperones also can influence metabolic processes. Here, we summarize several ways the Hsp90 and Hsp70 chaperone families act on human metabolic enzymes and their supramolecular assemblies to change enzymatic activities and metabolite flux. We further highlight how these chaperones can assist in the translocation and degradation of metabolic enzymes. Collectively, these studies provide a new view for how metabolic processes are regulated to meet cellular demand and inspire new avenues for therapeutic intervention.

Binding Mechanism of Inhibitors to Heat Shock Protein 90 Investigated by Multiple Independent Molecular Dynamics Simulations and Prediction of Binding Free Energy

The heat shock protein (HSP90) has been an import target of drug design in the treatment of human disease. An exploration of the conformational changes in HSP90 can provide useful information for the development of efficient inhibitors targeting HSP90. In this work, multiple independent all-atom molecular dynamics (AAMD) simulations followed by calculations of the molecular mechanics generalized Born surface area (MM-GBSA) were performed to explore the binding mechanism of three inhibitors (W8Y, W8V, and W8S) to HSP90. The dynamics analyses verified that the presence of inhibitors impacts the structural flexibility, correlated movements, and dynamics behavior of HSP90. The results of the MM-GBSA calculations suggest that the selection of GB models and empirical parameters has important influences on the predicted results and verify that van der Waals interactions are the main forces that determine inhibitor-HSP90 binding. The contributions of separate residues to the inhibitor-HSP90 binding process indicate that hydrogen-bonding interactions (HBIs) and hydrophobic interactions play important roles in HSP90-inhibitor identifications. Moreover, residues L34, N37, D40, A41, D79, I82, G83, M84, F124, and T171 are recognized as hot spots of inhibitor-HSP90 binding and provide significant target sites of for the design of drugs related to HSP90. This study aims to contribute to the development of efficient inhibitors that target HSP90 by providing an energy-based and theoretical foundation.

Metal-enriched HSP90 nanoinhibitor overcomes heat resistance in hyperthermic intraperitoneal chemotherapy used for peritoneal metastases

Clinical hyperthermic intraperitoneal chemotherapy (HIPEC) is regarded as a potential treatment that can prolong survival of patients with peritoneal metastases after cytoreductive surgery. However, treated tumor cells are prone to becoming heat resistant to HIPEC therapy through high expression of heat shock proteins (HSPs). Here, a carrier-free bifunctional nanoinhibitor was developed for HIPEC therapy in the management of peritoneal metastases. Self-assembly of the nanoinhibitor was formed by mixing Mn ion and epigallocatechin gallate (EGCG) in a controllable manner. Such nanoinhibitor directly inhibited HSP90 and impaired the HSP90 chaperone cycle by reduced intracellular ATP level. Additionally, heat and Mn ion synergistically induced oxidative stress and expression of caspase 1, which activated GSDMD by proteolysis and caused pyroptosis in tumor cells, triggering immunogenic inflammatory cell death and induced maturation of dendritic cells through the release of tumor antigens. This strategy to inhibit heat resistance in HIPEC presented an unprecedented paradigm for converting "cold" tumors into "hot" ones, thus significantly eradicating disseminated tumors located deep in the abdominal cavity and stimulating immune response in peritoneal metastases of a mouse model. Collectively, the nanoinhibitor effectively induced pyroptosis of colon tumor cells under heat conditions by inhibiting heat stress resistance and increasing oxidative stress, which may provide a new strategy for treatment of colorectal peritoneal metastases.

Exploration of anti-stress mechanisms in high temperature exposed juvenile golden cuttlefish (Sepia esculenta) based on transcriptome profiling

Sepia esculenta is a cephalopod widely distributed in the Western Pacific Ocean, and there has been growing research interest due to its high economic and nutritional value. The limited anti-stress capacity of larvae renders challenges for their adaptation to high ambient temperatures. Exposure to high temperatures produces intense stress responses, thereby affecting survival, metabolism, immunity, and other life activities. Notably, the molecular mechanisms by which larval cuttlefish cope with high temperatures are not well understood. As such, in the present study, transcriptome sequencing of S. esculenta larvae was performed and 1,927 differentially expressed genes (DEGs) were identified. DEGs were subjected to functional enrichment analyses using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. The top 20 terms of biological processes in GO and 20 high-temperature stress-related pathways in KEGG functional enrichment analysis were identified. A protein-protein interaction network was constructed to investigate the interaction between temperature stress-related genes. A total of 30 key genes with a high degree of participation in KEGG signaling pathways or protein-protein interactions were identified and subsequently validated using quantitative RT-PCR. Through a comprehensive analysis of the protein-protein interaction network and KEGG signaling pathway, the functions of three hub genes (HSP90AA1, PSMD6, and PSMA5), which belong to the heat shock protein family and proteasome, were explored. The present results can facilitate further understanding of the mechanism of high temperature resistance in invertebrates and provide a reference for the S. esculenta industry in the context of global warming.