Hsp90-downregulation influences the heat-shock response, innate immune response and onset of oocyte development in nematodes

The neuron-specific IIS/FOXO transcriptome in aged animals reveals regulatory mechanisms of cognitive aging

Cognitive decline is a significant health concern in our aging society. Here, we used the model organism C. elegans to investigate the impact of the IIS/FOXO pathway on age-related cognitive decline. The daf-2 Insulin/IGF-1 receptor mutant exhibits a significant extension of learning and memory span with age compared to wild-type worms, an effect that is dependent on the DAF-16 transcription factor. To identify possible mechanisms by which aging daf-2 mutants maintain learning and memory with age while wild-type worms lose neuronal function, we carried out neuron-specific transcriptomic analysis in aged animals. We observed downregulation of neuronal genes and upregulation of transcriptional regulation genes in aging wild-type neurons. By contrast, IIS/FOXO pathway mutants exhibit distinct neuronal transcriptomic alterations in response to cognitive aging, including upregulation of stress response genes and downregulation of specific insulin signaling genes. We tested the roles of significantly transcriptionally-changed genes in regulating cognitive functions, identifying novel regulators of learning and memory. In addition to other mechanistic insights, a comparison of the aged vs young daf-2 neuronal transcriptome revealed that a new set of potentially neuroprotective genes is upregulated; instead of simply mimicking a young state, daf-2 may enhance neuronal resilience to accumulation of harm and take a more active approach to combat aging. These findings suggest a potential mechanism for regulating cognitive function with age and offer insights into novel therapeutic targets for age-related cognitive decline.

CUL-6/cullin ubiquitin ligase-mediated degradation of HSP-90 by intestinal lysosomes promotes thermotolerance

Heat shock can be a lethal stressor. Previously, we described a CUL-6/cullin-ring ubiquitin ligase complex in the nematode Caenorhabditis elegans that is induced by intracellular intestinal infection and proteotoxic stress and that promotes improved survival upon heat shock (thermotolerance). Here, we show that CUL-6 promotes thermotolerance by targeting the heat shock protein HSP-90 for degradation. We show that CUL-6-mediated lowering of HSP-90 protein levels, specifically in the intestine, improves thermotolerance. Furthermore, we show that lysosomal function is required for CUL-6-mediated promotion of thermotolerance and that CUL-6 directs HSP-90 to lysosome-related organelles upon heat shock. Altogether, these results indicate that a CUL-6 ubiquitin ligase promotes organismal survival upon heat shock by promoting HSP-90 degradation in intestinal lysosomes. Thus, HSP-90, a protein commonly associated with protection against heat shock and promoting degradation of other proteins, is itself degraded to protect against heat shock.

Hepatic immune response of Coilia nasus infected with Anisakidae during ovarian development

Anisakidae parasitism is a prevalent disease in wild populations of Coilia nasus, and can result in a significant loss of germplasm resources. To elucidate the immune response mechanism of C. nasus livers to Anisakidae infection, we collected and analysed 18 parasitic and 18 non-parasitic livers at gonadal developmental stages II, III, and V using histopathology, molecular biology and transcriptome methods. The hepatic portal area of the parasitic group exhibited an increase in the fibrous stroma and thickened hepatic arteries with positive Ly-6G staining, indicating inflammation and immune responses in the liver. Hepatocyte cytokine levels and the expression of liver function-related genes indicated that fish livers responded similarly to Anisakidae parasitism across different gonadal developmental stages. Oxidative stress indices showed more intense changes in stage II samples, whereas gene expression levels of Nrf2 and C3 were significantly increased in parasitised livers during stage III and V. Liver transcriptome sequencing identified 2575 differentially expressed genes between the parasitic and non-parasitic groups at the three gonadal developmental stages. KEGG pathway analysis showed that natural killer cell-mediated cytotoxicity, the NOD-like receptor signaling pathway, neutrophil extracellular trap formation, and other immune pathways were significantly enriched. Expression patterns varied across developmental stages, suggesting that innate immunity was primarily responsible for the liver immune response to Anisakidae infection during C. nasus migration, possibly related to water temperature changes or shifts in the gonadal developmental stage. In summary, this study investigated the immune response of C. nasus to Anisakidae parasitism under natural conditions, focusing on reproductive aspects and environmental changes, thereby establishing a foundation for elucidating the molecular mechanisms underlying the immune response of Anisakidae in C. nasus.

Temperature Effects on Expression Levels of hsp Genes in Eggs and Second-Stage Juveniles of Meloidogyne hapla Chitwood, 1949

Meloidogyne hapla is one of the most important nematode pathogens. It is a sedentary, biotrophic parasite of plants that overwinters in the soil or in diseased roots. The development of M. hapla is temperature dependent. Numerous studies have been performed on the effect of temperature on the development of M. hapla, but only a few of them analyzed the heat shock protein (hsp) genes. The aim of the study was to perform expression profiling of eight hsp genes (Mh-hsp90, Mh-hsp1, Mh-hsp4, Mh-hsp6, Mh-hsp60, Mh-dnj19, Mh-hsp43, and Mh-hsp12.2) at two development stages of M. hapla, i.e., in eggs and second-stage juveniles (J2). The eggs and J2 were incubated under cold stress (5 °C), heat stress (35 °C, 40 °C), and non-stress (10 °C, 20 °C, and 30 °C) conditions. Expression profiling was performed by qPCR. It was demonstrated that only two genes, Mh-hsp60 and Mh-dnj19, have been upregulated by heat and cold stress at both development stages. Heat stress upregulated the expression of more hsp genes than cold stress did. The level of upregulation of most hsp genes was more marked in J2 than in eggs. The obtained results suggest that the Mh-hsp90 and Mh-hsp1 genes can be used as bioindicators of environmental impacts on nematodes of the Meloidogyne genus.

Kaempferol exerts antioxidant effects in age-related diminished ovarian reserve by regulating the HSP90/NRF2 pathway

Kaempferol is the active ingredient of Er-Xian decoction (EXD), a traditional Chinese medicine formula used clinically to treat ovarian dysfunction, but the mechanism of kaempferol relieving age-related diminished ovarian reserve (AR-DOR) is still unclear. In this study, 36 volunteers and 78 DOR patients (37 patients with EXD treatment) were enrolled in the clinical research. Meanwhile, 32-week-old female mice were used to establish the AR-DOR model, and these model mice were intragastrically administered with 100 mg/kg kaempferol in the presence or absence of 200 mg/kg geranylgeranylacetone (GGA) or 1 mg/kg geldanamycin (GDA). The effects of kaempferol on serum hormone levels and oxidative stress-related indexes were detected by enzyme-linked immunosorbent assay. Antral follicle count (AFC) was determined by hematoxylin-eosin staining. The protein levels of HSP90 and nuclear factor erythroid 2-related factor 2 (NRF2) were assayed by Western blot. This study displayed that the serum anti-Mullerian hormone (AMH) level in DOR patients with EXD treatment was higher than that in DOR patients without EXD treatment. Kaempferol treatment reversed the low levels of AMH, estradiol (E2), AFC, superoxide dismutase (SOD), and catalase (CAT), as well as the high levels of follicle-stimulating hormone (FSH), reactive oxygen species (ROS), and malonaldehyde (MDA). The results showed that HSP90 was predicted to have high affinity with kaempferol, and its expression was inhibited by kaempferol, while the expression of NRF2, the target of HSP90, was up-regulated by kaempferol. However, the above effects of kaempferol were reversed by GGA. On the contrary, GDA enhanced the therapeutic effects of kaempferol on AR-DOR mice. Moreover, the treatment of kaempferol resulted in a reduction in the phosphorylation level of heat shock factor 1 (HSF1), the transcription factor associated with HSP90, and an increase in the phosphorylation level of Src, a client protein of HSP90. In summary, kaempferol exerts an antioxidant effect on AR-DOR by inhibiting HSP90 expression to up-regulate NRF2 expression. This study provides a theoretical basis for the clinical application of kaempferol in AR-DOR.

Heat Shock Proteins as Potential Indicators of Induced Stress in Nematodes

Heat shock proteins (HSPs) in all animals studied to date constitute potential indicators of stress, under various environmental conditions. The goal of this chapter is to show, for the first time, the suitability of the approach based on evaluation of the expression levels of heat shock proteins, as good indicators of stress induced in nematodes by the cultivation of resistant plant varieties or by other potential stressors.

Protective effect of Gastrodia elata Blume in a Caenorhabditis elegans model of Alzheimer's disease based on network pharmacology

The aim of the present study was to investigate the protective effect of Gastrodia elata Blume (GEB) against Caenorhabditis elegans (C. elegans) in Alzheimer's disease (AD) through network pharmacology. Firstly, the active constituents of GEB through ETCM and BATMAN-TCM databases were collected and its potential AD-related targets in Swiss Target Prediction were predicted. The potential targets related to AD were collected from the GeneCards, OMIM, CTD and DisGeNET databases, and the differential genes (DEGs) between the normal population and the AD patient population in GSE5281 chip of the Gene Expression Omnibus database were collected at the same time. The intersection of the three targets yielded 59 key targets of GEB for the treatment of AD. The drug-active ingredient-target-AD network diagram was constructed and visualized with Cytoscape software to obtain the core components. Subsequently, protein-protein interaction analysis (PPI) was performed on 59 key targets through STRING database, and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses was performed on 59 key targets. Finally, molecular docking was conducted between core components and core targets using AutoDock software, and the C. elegans AD model was used for experimental verification to explore the regulatory paralysis effect of core components on the C. elegans model, β-amyloid (Aβ) plaque deposition, and quantitative polymerase chain reaction verification of the regulatory effect of components on targets. The GEB components 4,4'-dihydroxydiphenyl methane (DM) and protocatechuic aldehyde (PA) were found to be most strongly associated with AD, and five core targets were identified in the PPI network, including GAPDH, EP300, HSP90AB1, KDM6B, and CREBBP. In addition to GAPDH, the other four targets were successfully docked with DM and PA using AutoDock software. Compared with the control group, 0.5 mM DM and 0.25 mM PA significantly delayed C. elegans paralysis (P<0.01), and inhibited the aggregation of Aβ plaques in C. elegans. Both DM and PA could upregulate the expression level of core target gene HSP90AB1 (P<0.01), and DM upregulated the expression of KDM6B (P<0.01), suggesting that DM and PA may be potential active components of GEB in the treatment of AD.

Transcellular chaperone signaling is an intercellular stress-response distinct from the HSF-1-mediated heat shock response

Organismal proteostasis is maintained by intercellular signaling processes including cell nonautonomous stress responses such as transcellular chaperone signaling (TCS). When TCS is activated upon tissue-specific knockdown of hsp-90 in the Caenorhabditis elegans intestine, heat-inducible hsp-70 is induced in muscle cells at the permissive temperature resulting in increased heat stress resistance and lifespan extension. However, our understanding of the molecular mechanism and signaling factors mediating transcellular activation of hsp-70 expression from one tissue to another is still in its infancy. Here, we conducted a combinatorial approach using transcriptome RNA-Seq profiling and a forward genetic mutagenesis screen to elucidate how stress signaling from the intestine to the muscle is regulated. We find that the TCS-mediated "gut-to-muscle" induction of hsp-70 expression is suppressed by HSF-1 and instead relies on transcellular-X-cross-tissue (txt) genes. We identify a key role for the PDZ-domain guanylate cyclase txt-1 and the homeobox transcription factor ceh-58 as signaling hubs in the stress receiving muscle cells to initiate hsp-70 expression and facilitate TCS-mediated heat stress resistance and lifespan extension. Our results provide a new view on cell-nonautonomous regulation of "inter-tissue" stress responses in an organism that highlight a key role for the gut. Our data suggest that the HSF-1-mediated heat shock response is switched off upon TCS activation, in favor of an intercellular stress-signaling route to safeguard survival.

Organismal Roles of Hsp90

Heat shock protein 90 (Hsp90) is a highly conserved molecular chaperone that assists in the maturation of many client proteins involved in cellular signal transduction. As a regulator of cellular signaling processes, it is vital for the maintenance of cellular proteostasis and adaptation to environmental stresses. Emerging research shows that Hsp90 function in an organism goes well beyond intracellular proteostasis. In metazoans, Hsp90, as an environmentally responsive chaperone, is involved in inter-tissue stress signaling responses that coordinate and safeguard cell nonautonomous proteostasis and organismal health. In this way, Hsp90 has the capacity to influence evolution and aging, and effect behavioral responses to facilitate tissue-defense systems that ensure organismal survival. In this review, I summarize the literature on the organismal roles of Hsp90 uncovered in multicellular organisms, from plants to invertebrates and mammals.

Transcriptome sequencing reveals core regulation modules and gene signatures of Zusanli acupoints in response to different moxibustion warm stimulation in adjuvant arthritis rat

Background

The efficacy of moxibustion in treating rheumatoid arthritis is recognized, but its molecular mechanism is still unclear. This study aimed to characterize the molecular map and potential key genes in the process of different moxibustion warm at Zusanli acupoint treatment of adjuvant arthritis (AA) model.

Methods

AA rat model was induced by complete Freund’s adjuvant (CFA) and then accessed by foot swelling and thermal hyperalgesia test. Transcriptome sequencing, series test of cluster (STC) and weighted gene co-expression network analysis (WGCNA) were used in this study.

Results

CFA-induced inflammation, foot swelling, and pain in AA rats were significantly improved by moxibustion warm. Differentially expressed genes (DEGs) were screened in nine different comparison groups and a total of 4535 DEGs were identified, and these DEGs were preferentially clustered in inflammatory and immune-related pathways, such as MAPK signaling pathway. Only 1 DEG of heat shock protein 90, alpha (cytosolic), class A member 1 (Hsp90aa1) was shared in comparison groups of model with moxibustion treatment. STC analysis also revealed that Hsp90aa1 was increased in AA model, but decreased after 37 °C moxibustion intervention, and constantly decreased after 42 °C moxibustion treatment. GO and KEGG pathway analysis revealed that these genes enriched in inflammatory and immune-related pathways. Moreover, WGCNA identified that violet module was positively correlated with model temperature while negatively correlated with control, and the paleturquoise module was positively correlated with model. The violet and paleturquoise module gene were significantly enriched in MAPK signaling pathway. Importantly, Hsp90aa1 also played a central role in the violet module by interacting with multiple proteins.

Conclusions

Moxibustion warm improved AA in rat, and we obtained the transcriptome profile and excavate a critical gene of Hsp90aa1, and provided insight into gene signatures for moxibustion warm at Zusanli acupoint in AA rat.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41065-022-00221-4.

Induction of oxidative stress and apoptosis in the injured brain: potential relevance to brain regeneration in zebrafish

Recent findings suggest a significant role of the brain-derived neurotrophic factor (BDNF) as a mediator of brain regeneration following a stab injury in zebrafish. Since BDNF has been implicated in many physiological processes, we hypothesized that these processes are affected by brain injury in zebrafish. Hence, we examined the impact of stab injury on oxidative stress and apoptosis in the adult zebrafish brain. Stab wound injury (SWI) was induced in the right telencephalic hemisphere of the adult zebrafish brain and examined at different time points. The biochemical variables of oxidative stress insult and transcript levels of antioxidant genes were assessed to reflect upon the oxidative stress levels in the brain. Immunohistochemistry was performed to detect the levels of early apoptotic marker protein cleaved caspase-3, and the transcript levels of pro-apoptotic and anti-apoptotic genes were examined to determine the effect of SWI on apoptosis. The activity of antioxidant enzymes, the level of lipid peroxidation (LPO) and reduced glutathione (GSH) were significantly increased in the injured fish brain. SWI also enhanced the expression of cleaved caspase-3 protein and apoptosis-related gene transcripts. Our results indicate induction of oxidative stress and apoptosis in the telencephalon of adult zebrafish brain by SWI. These findings contribute to the overall understanding of the pathophysiology of traumatic brain injury and adult neurogenesis in the zebrafish model and raise new questions about the compensatory physiological mechanisms in response to traumatic brain injury in the adult zebrafish brain.

hsp-90 and unc-45 depletion induce characteristic transcriptional signatures in coexpression cliques of C. elegans

Nematode development is characterized by progression through several larval stages. Thousands of genes were found in large scale RNAi-experiments to block this development at certain steps, two of which target the molecular chaperone HSP-90 and its cofactor UNC-45. Aiming to define the cause of arrest, we here investigate the status of nematodes after treatment with RNAi against hsp-90 and unc-45 by employing an in-depth transcriptional analysis of the arrested larvae. To identify misregulated transcriptional units, we calculate and validate genome-wide coexpression cliques covering the entire nematode genome. We define 307 coexpression cliques and more than half of these can be related to organismal functions by GO-term enrichment, phenotype enrichment or tissue enrichment analysis. Importantly, hsp-90 and unc-45 RNAi induce or repress many of these cliques in a coordinated manner, and then several specifically regulated cliques are observed. To map the developmental state of the arrested nematodes we define the expression behaviour of each of the cliques during development from embryo to adult nematode. hsp-90 RNAi can be seen to arrest development close to the L4 larval stage with further deviations in daf-16 regulated genes. unc-45 RNAi instead leads to arrested development at young adult stage prior to the programmatic downregulation of sperm-cell specific genes. In both cases processes can be defined to be misregulated upon depletion of the respective chaperone. With most of the defined gene cliques showing concerted behaviour at some stage of development from embryo to late adult, the “clique map” together with the clique-specific GO-terms, tissue and phenotype assignments will be a valuable tool in understanding concerted responses on the genome-wide level in Caenorhabditis elegans.

Expanding the Organismal Proteostasis Network: Linking Systemic Stress Signaling with the Innate Immune Response

Stress response pathways regulate proteostasis and mitigate macromolecular damage to promote long-term cellular health. Intercellular signaling is an essential layer of systemic proteostasis in an organism and is facilitated via transcellular signaling molecules that orchestrate the activation of stress responses across tissues and organs. Accumulating evidence indicates that components of the immune response act as signaling factors that regulate the cell-non-autonomous proteostasis network. Here, we review emergent advances in our understanding of cell-non-autonomous regulators of proteostasis networks in multicellular settings, from the model organism, Caenorhabditis elegans, to humans. We further discuss how innate immune responses can be players of the organismal proteostasis network and discuss how both are linked in cancer.

Genome-wide analysis of yeast expression data based on a priori generated co-regulation cliques

DNA microarrays are highly sensitive tools to evaluate the gene expression status of organismic samples and standardized array formats exist for many different sample types. Differential expression studies usually utilize the strongest upor downregulated genes to generate networks visualizing the relationships among these genes. To include all yeast genes in one analysis and to get broader information on all cellular responses, we test a priori input of predefined genome-wide expression cliques and subsequent statistical analysis of the expression data. To this end, we generate a set of 72 co-regulation cliques using the information from 3196 microarray experiments. The obtained cliques performed highly significant in gene ontology and transcription factor enrichment analyses. We then tested the clique set on individual microarray experiments reporting on responses to pheromone, glycerol versus glucose based growth and the cellular response to heat. In all cases a highly significant determination of affected expression cliques was possible based on their average expression differences, the positions of their genes within hit rankings (UpRegScore) or the enrichment of the Top200 hits in certain cliques. The 72 cliques were finally used to compare experiments, which reported on the transcriptional response to polyglutamine proteins of different lengths. Using the predefined clique set it is possible to identify with high sensitivity and good significance sample and condition specific changes to gene expression. We thus conclude that an analysis, starting with these 72 preformed expression cliques, can complement traditional microarray analyses by visualizing the entire response on a static genome-wide gene set.

Regulation of the Hsp90 system

Hsp90 is a highly conserved and abundant chaperone. It participates in essential cellular activities by supporting the maturation process of its client proteins, many of which are protein kinases and steroid receptors. Client processing is achieved via extensive conformational changes within the dimeric chaperone. This requires an ATP hydrolysis activity that is controlled by auto-inhibitory mechanisms and several structurally diverse cofactors. Especially the client-specificity of Hsp90 depends on client-specific cofactors, which can adapt Hsp90's activities to the client requirements at different conditions and in different cell types. Additionally, post-translational modifications can influence almost every aspect of Hsp90's interactions and activities. In this review, we present these regulatory principles, discuss the factors that have an impact on Hsp90's function and elaborate the mechanisms that are responsible for regulating the Hsp90 machinery.