Heat shock transcription factor HSF1 maintains proteome integrity via the induction of heat shock proteins. Here, we provide a comprehensive overview on the structure, function and regulation of HSF1 in multiple organisms. We summarize the aging-associated changes of HSF1 function, the reduced inducibility of the heat shock response, leading to a model of age-related stochastic HSF1 activity decline. Besides, we review basal, non-canonic HSF1 functions through regulating distinct transcriptional outputs which support development, reproduction, tissue proteostasis maintenance, growth- and cancer-related anabolic processes. Based on major observations in the nematode C. elegans demonstrating differential regulation of these outputs, we propose a novel mechanistic framework that draws on the life history-coupled programmed remodeling of its transcriptional function at the onset of reproduction. The HSF1 output selection model accounts for the coexistence of diminished stress inducibility with sustained or increased basal HSF1 activity and explains why broad HSF1 activation may benefit proteotoxic diseases but pose risks in cancer-prone conditions. Experimental approaches leveraging age- and tissue-specific transcriptomic, chromatin, and post-translational analyses are outlined, emphasizing selective restoration of protective HSF1 outputs over indiscriminate activation.

BackgroundExcessive alcohol consumption is a global health issue and a leading cause of disease, disability, and mortality. This study aimed to determine the effects of a 24-hour ethanol exposure, post-exposure withdrawal (cessation of alcohol intake), and post-exposure withdrawal relief on the sensorimotor performance of the nematode Caenorhabditis elegans.MethodsA modified kinetic chemotaxis assay (commonly referred as "diacetyl race") was conducted with worm populations subjected to three different doses of ethanol pre-exposure to assess the impact of ethanol on locomotion. Additionally, we employed lifespan, mobility, gene expression analysis and imaging assays to evaluate health status and molecular alterations occurring in the worms under different levels of ethanol exposure.ResultsWild-type, dopamine receptor mutant and serotonin biosynthesis null mutant worms presented different responses to ethanol in the kinetic chemotaxis assay. Furthermore, exposure to ethanol altered vesicle exocytosis in dopaminergic and serotonergic neurons and the expression of a panel of genes associated with stress responses. Additionally, 24-hour ethanol exposure differentially influenced the lifespan of wild-type and mutant worms.ConclusionsDifferent responses, which may be relevant to the pathogenesis of human alcohol use disorder, were observed in wild-type worms, a dopamine receptor mutant, and a serotonin biosynthesis null mutant in a variety of assays performed. Furthermore, we present a 3-step experimental model for drug tolerance, based on the well-established kinetic chemotaxis behavioral paradigm ("diacetyl race"). This model provides new insights into the effects of alcohol in worms, particularly regarding the roles of dopamine and serotonin neurotransmission. Importantly, this model holds potential for investigating the effects of other addictive substances beyond alcohol.

Infections, such as that by the multiresistant opportunistic bacterial pathogen Pseudomonas aeruginosa, may pose a serious health risk, especially on vulnerable patient populations. The nematode Caenorhabditis elegans provides a simple organismal model to investigate both pathogenic mechanisms and the emerging role of innate immunity in host protection. Here, we review the virulence and infection strategies of P. aeruginosa and host defenses of C. elegans. We summarize the recognition mechanisms of patterns of pathogenesis, including novel pathogen-associated molecular patterns and surveillance immunity of translation, mitochondria, and lysosome-related organelles. We also review the regulation of antimicrobial and behavioral defenses by the worm’s neuroendocrine system. We focus on how discoveries in this rich field align with well-characterized evolutionary conserved protective pathways, as well as on potential crossovers to human pathogenesis and innate immune responses.

Proteostasis maintenance and lipid metabolism are critical for survival and promote longevity, however, their coordination is largely unclear. Here we show that the heat shock factor HSF-1 and the proteostasis state regulates lipolysis in C. elegans . We find that in response to starvation, the sirtuin 1 ortholog SIR-2.1 activates lipolysis by upregulation of the adipose triglyceride lipase ATGL-1. In feeding worms, intestinal HSF-1 represses ATGL-1 expression and lipolysis via the microRNA system. In starving worms, SIR-2.1 suspends a miR-53- mediated suppression of lipolysis by inhibiting its HSF-1-dependent expression. The apparent antagonism of SIR-2.1 and HSF-1, distinct from their synergism at heat shock promoters suggests a context-specific regulation of HSF-1 by SIR-2.1. We demonstrate that the SIR-2.1 and protein kinase A pathways are both indispensable, and independently converge on ATGL- 1 for lipolysis. HSF-1 activation by proteostasis disturbances inhibits starvation-induced lipid mobilization, whereas its age-related decline limits fat deposition through atgl-1 . Our findings reveal a crosstalk between proteostasis and lipid/energy metabolism, which may modulate stress resilience and aging.### Competing Interest StatementThe authors have declared no competing interest.

Prostate cancer metastasis is a significant cause of mortality in men. PKD3 facilitates tumor growth and metastasis, however, its regulation is largely unclear. The Hsp90 chaperone stabilizes an array of signaling client proteins, thus is an enabler of the malignant phenotype. Here, using different prostate cancer cell lines, we report that Hsp90 ensures PKD3 conformational stability and function to promote cancer cell migration. We found that pharmacological inhibition of either PKDs or Hsp90 dose-dependently abrogated the migration of DU145 and PC3 metastatic prostate cancer cells. Hsp90 inhibition by ganetespib caused a dose-dependent depletion of PKD2, PKD3, and Akt, which are all involved in metastasis formation. Proximity ligation assay and immunoprecipitation experiments demonstrated a physical interaction between Hsp90 and PKD3. Inhibition of the chaperone–client interaction induced misfolding and proteasomal degradation of PKD3. PKD3 siRNA combined with ganetespib treatment demonstrated a specific involvement of PKD3 in DU145 and PC3 cell migration, which was entirely dependent on Hsp90. Finally, ectopic expression of PKD3 enhanced migration of non-metastatic LNCaP cells in an Hsp90-dependent manner. Altogether, our findings identify PKD3 as an Hsp90 client and uncover a potential mechanism of Hsp90 in prostate cancer metastasis. The molecular interaction revealed here may regulate other biological and pathological functions.

Lysosome-related organelles (LROs) play diverse roles and their dysfunction causes immunodeficiency. However, their primordial functions remain unclear. Here, we report that C. elegans LROs (gut granules) promote organismal defenses against various stresses. We find that toxic benzaldehyde exposure induces LRO autofluorescence, stimulates the expression of LRO-specific genes and enhances LRO transport capacity as well as increases tolerance to benzaldehyde, heat and oxidative stresses, while these responses are impaired in glo-1/Rab32 and pgp-2 ABC transporter LRO biogenesis mutants. Benzaldehyde upregulates glo-1- and pgp-2-dependent expression of heat shock, detoxification and antimicrobial effector genes, which requires daf-16/FOXO and/or pmk-1/p38MAPK. Finally, benzaldehyde preconditioning increases resistance against Pseudomonas aeruginosa PA14 in a glo-1- and pgp-2-dependent manner, and PA14 infection leads to the deposition of fluorescent metabolites in LROs and induction of LRO genes. Our study suggests that LROs may play a role in systemic responses to stresses and in pathogen resistance.

Assuring a healthy proteome is indispensable for survival and organismal health. Proteome disbalance and the loss of the proteostasis buffer are hallmarks of various diseases. The essential molecular chaperone Hsp90 is a regulator of the heat shock response via HSF1 and a stabilizer of a plethora of signaling proteins. In this review, we summarize the role of Hsp90 in the cellular and organismal regulation of proteome maintenance.

While the elderly segment of the population continues growing in importance, neurodegenerative diseases increase exponentially. Lifestyle factors such as nutrition, exercise, and education, among others, influence ageing progression, throughout life. Notably, the Central Nervous System (CNS) can benefit from nutritional strategies and dietary interventions that prevent signs of senescence, such as cognitive decline or neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s Disease. The dietary polyphenol Resveratrol (RV) possesses antioxidant and cytoprotective effects, producing neuroprotection in several organisms. The oxidative stress (OS) occurs because of Reactive oxygen species (ROS) accumulation that has been proposed to explain the cause of the ageing. One of the most harmful effects of ROS in the cell is DNA damage. Nevertheless, there is also evidence demonstrating that OS can produce other molecular changes such as mitochondrial dysfunction, inflammation, apoptosis, and epigenetic modifications, among others. Interestingly, the dietary polyphenol RV is a potent antioxidant and possesses pleiotropic actions, exerting its activity through various molecular pathways. In addition, recent evidence has shown that RV mediates epigenetic changes involved in ageing and the function of the CNS that persists across generations. Furthermore, it has been demonstrated that RV interacts with gut microbiota, showing modifications in bacterial composition associated with beneficial effects. In this review, we give a comprehensive overview of the main mechanisms of action of RV in different experimental models, including clinical trials and discuss how the interconnection of these molecular events could explain the neuroprotective effects induced by RV.

Recognition of stress and mobilization of adequate “fight-or-flight” responses is key for survival and health. Previous studies have shown that exposure of Caenorhabditis elegans to pathogens or toxins simultaneously stimulates cellular stress and detoxification responses and aversive behavior. However, whether a coordinated regulation exists between cytoprotective stress responses and behavioral defenses remains unclear. Here, we show that exposure of C. elegans to high concentrations of naturally attractive food-derived odors, benzaldehyde and diacetyl, induces toxicity and food avoidance behavior. Benzaldehyde preconditioning activates systemic cytoprotective stress responses involving DAF-16/FOXO, SKN-1/Nrf2, and Hsp90 in non-neuronal cells, which confer both physiological (increased survival) and behavioral tolerance (reduced food avoidance) to benzaldehyde exposure. Benzaldehyde preconditioning also elicits behavioral cross-tolerance to the structurally similar methyl-salicylate, but not to the structurally unrelated diacetyl. In contrast, diacetyl preconditioning augments diacetyl avoidance, weakens physiological diacetyl tolerance, and does not induce apparent molecular defenses. The inter-tissue connection between cellular and behavioral defenses is mediated by JNK-like stress-activated protein kinases and the neuropeptide Y receptor NPR-1. Reinforcement of the stressful experiences using spaced training forms stable stress-specific memories. Memory retrieval by the olfactory cues leads to avoidance of food contaminated by diacetyl and context-dependent behavioral decision to avoid benzaldehyde only if there is an alternative, food-indicative odor. Our study reveals a regulatory link between conserved cytoprotective stress responses and behavioral avoidance, which underlies “fight-or-flight” responses and facilitates self-protection in real and anticipated stresses. These findings imply that variations in the efficiency of physiological protection during past episodes of stress might shape current behavioral decisions.

Exercise elicits a systemic adaptation reaction, involving both neuroendocrine and cellular/paracrine stress responses, exemplified by the sympathoadrenergic activity and the release of cellular Hsp70 into the circulation. Regular sports training is known to result in increased fitness. In this study, we characterized the plasma norepinephrine and Hsp70 levels and modeled their relationship in response to exercise stress by bicycle ergometer in 12 trained judoka athletes and in 10 healthy controls. Resting norepinephrine was similar in both groups, whereas Hsp70 was significantly higher in controls compared to athletes. Intense exercise load induced both norepinephrine and Hsp70 elevation. However, both norepinephrine and Hsp70 were significantly lower in athletes compared to the control group. A reaction kinetic model was developed that provided a quantitative description of norepinephrine-facilitated extracellular Hsp70 release, congruent with the experimental data. Our study indicates that exercise-induced norepinephrine and extracellular Hsp70 may be coordinated responses to physiological stress, which are robustly affected by regular sports activity.

Integrative medicine is a new approach in the 21st century healthcare system, which integrates conventional medicine and evidence-based, safe and efficient complementary therapies into a unified biomedicine. Medical doctors and complementary therapists work together in partnership with patients to help them recover and live a whole life. Equally important is the maintenance and enhancement of health and well-being in which therapists become role-models. In this article, the authors introduce a proposal for the concept and major elements of a two-year integrative medicine postgraduate training for specialist doctors in Hungary and summarize international progress in the field. Orv Hetil. 2020; 161(27): 1122-1130.

Graph theoretical analyses of nervous systems usually omit the aspect of connection polarity, due to data insufficiency. The chemical synapse network of Caenorhabditis elegans is a well-reconstructed directed network, but the signs of its connections are yet to be elucidated. Here, we present the gene expression-based sign prediction of the ionotropic chemical synapse connectome of C. elegans (3,638 connections and 20,589 synapses total), incorporating available presynaptic neurotransmitter and postsynaptic receptor gene expression data for three major neurotransmitter systems. We made predictions for more than two-thirds of these chemical synapses and observed an excitatory-inhibitory (E:I) ratio close to 4:1 which was found similar to that observed in many real-world networks. Our open source tool (http://EleganSign.linkgroup.hu) is simple but efficient in predicting polarities by integrating neuronal connectome and gene expression data.

Stress exposure early in life is implicated in various behavioural and somatic diseases. Experiences during the critical perinatal period form permanent, imprinted memories promoting adult survival. Although imprinting is widely recognized to dictate behaviour, whether it actuates specific transcriptional responses at the cellular level is unknown. Here we report that in response to early life stresses, Caenorhabditis elegans nematodes form an imprinted cellular defense memory. We show that exposing newly-born worms to toxic antimycin A and paraquat, respectively, stimulates the expression of toxin-specific cytoprotective reporters. Toxin exposure also induces avoidance of the toxin-containing bacterial lawn. In contrast, adult worms do not exhibit aversive behaviour towards stress-associated bacterial sensory cues. However, the mere re-encounter with the same cues reactivates the previously induced cytoprotective reporters. Learned adult defenses require memory formation during the L1 larval stage and do not appear to confer increased protection against the toxin. Thus, exposure of C. elegans to toxic stresses in the critical period elicits adaptive behavioural and cytoprotective responses, which do not form imprinted aversive behaviour, but imprint a cytoprotective memory. Our findings identify a novel form of imprinting and suggest that imprinted molecular defenses might underlie various pathophysiological alterations related to early life stress.

In this paper, performance analyses of mechanical systems having ideal/non-ideal kinematic joints and pseudo joint (flexural pivot connection) are investigated. A 3D slider-crank mechanism is considered for computational and experimental studies. Power consumption of main actuator is evaluated in case of different clearance sizes, diameters of small flexural pivot and driving speeds. Hertz contact theory comprising the Lankarani and Nikravesh model is considered to describe the contact forces in the clearance joint. In order to overcome the computational drawbacks, a modified Coulomb's friction model is preferred to define the friction effects between matting parts in the clearance joint. Same mechanism models are also used in the experimental stage to measure the real change in the actuator current. Even if the same working parameters are performed, the outputs of this study outline that the clearance in a joint can cause a crucial increase in the current level of actuator. Irregular current fluctuation on actuator can also lead to undesired effects on the actuator lifetime and power consumption. Suitable diameter of the flexural pivot is a solution to decrease the amplitude and peak frequency values of motor currents. Particularly, small pivot diameter can be used as a design variable to decrease the actuator current level at the higher working velocity. This may be an advantage to make the motor lifetime longer, to decrease the power consumption and to prevent the thermal problem in electric motors.

Feeding rats with high-fat diet (HFD) with a single streptozotocin (STZ) injection induced obesity, slightly elevated fasting blood glucose and impaired glucose and insulin tolerance, and caused cardiac hypertrophy and mild diastolic dysfunction as published before by Koncsos et al. in 2016. Here we aimed to explore the renal consequences in the same groups of rats. Male Long-Evans rats were fed normal chow (CON; n = 9) or HFD containing 40% lard and were administered STZ at 20 mg/kg (i.p.) at week four (prediabetic rats, PRED, n = 9). At week 21 blood and urine samples were taken and kidney and liver samples were collected for histology, immunohistochemistry and for analysis of gene expression. HFD and STZ increased body weight and visceral adiposity and plasma leptin concentration. Despite hyperleptinemia, plasma C-reactive protein concentration decreased in PRED rats. Immunohistochemistry revealed elevated collagen IV protein expression in the glomeruli, and Lcn2 mRNA expression increased, while Il-1β mRNA expression decreased in both the renal cortex and medulla in PRED vs. CON rats. Kidney histology, urinary protein excretion, plasma creatinine, glomerular Feret diameter, desmin protein expression, and cortical and medullary mRNA expression of TGF-β1, Nrf2, and PPARγ were similar in CON and PRED rats. Reduced AMPKα phosphorylation of the autophagy regulator Akt was the first sign of liver damage, while plasma lipid and liver enzyme concentrations were similar. In conclusion, glomerular collagen deposition and increased lipocalin-2 expression were the early signs of kidney injury, while most biomarkers of inflammation, oxidative stress and fibrosis were negative in the kidneys of obese, prediabetic rats with mild heart and liver injury.

The FOXO transcription factor family is a conserved regulator of longevity and the downstream target of insulin/insulin-like signaling. In Caenorhabditis elegans , the FOXO ortholog DAF-16A and D/F isoforms extend lifespan in daf - 2 insulin-like receptor mutants. Here we identify the DAF-21/Hsp90 chaperone as a longevity regulator. We find that reducing DAF-21 capacity by daf - 21 ( RNAi ) initiated either at the beginning or at the end of larval development shortens wild-type lifespan. daf - 21 knockdown employed from the beginning of larval development also decreases longevity of daf - 2 mutant and daf -2 silenced nematodes. daf - 16 loss-of-function mitigates the lifespan shortening effect of daf - 21 silencing. We demonstrate that DAF-21 specifically promotes daf - 2 and heat-shock induced nuclear translocation of DAF-16A as well as the induction of DAF-16A-specific mRNAs, without affecting DAF-16D/F localization and transcriptional function. DAF-21 is dispensable for the stability and nuclear import of DAF-16A, excluding a chaperone-client interaction and suggesting that DAF-21 regulates DAF-16A activation upstream of its cellular traffic. Finally, we show a selective requirement for DAF-21 to extend lifespan of DAF-16A, but not DAF-16D/F, transgenic daf - 2 mutant strains. Our findings indicate a spatiotemporal determination of multiple DAF-21 roles in fertility, development and longevity and reveal an isoform-specific regulation of DAF-16 activity.

Sirtuin 1 (SIRT1) othologs are ubiquitous NAD+-dependent deacetylases that act as nutrient sensors and modulate metabolism and stress responses in diverse organisms. Both mammalian SIRT1 and Caenorhabditis elegans SIR-2.1 have been implicated in dietary restriction, longevity, and healthspan. Hsp90 is an evolutionarily conserved molecular chaperone that stabilizes a plethora of signaling ’client’ proteins and regulates fundamental biological processes. Here we report that Hsp90 is required for conformational stabilization of SIRT1 and SIR-2.1. We find that inhibition of Hsp90 by geldanamycin (GA) induces the depletion of mammalian SIRT1 protein in a concentration and time dependent manner in COS-7 and HepG2 cells. In contrast to SIRT1, SIRT2 level remains unchanged by GA treatment, reflecting a specific Hsp90 SIRT1 interaction. Hsp90 inhibition leads to the destabilization and proteasomal degradation of SIRT1. Moreover, we observe a GA-sensitive physical interaction between SIRT1 and Hsp90 by immunoprecipitation. We also demonstrate that hsp-90 gene silencing also induces SIR-2.1 protein depletion and proteasomal degradation in C. elegans. Our findings identify metazoan SIRT1 orthologs as Hsp90 clients and reveal a novel crosstalk between the proteostasis and nutrient signaling networks, which may have implications in various age related diseases.

The Ras GTPase activating proteins (RasGAPs) are regulators of the conserved Ras/MAPK pathway. Various roles of some of the RasGAPs in learning and memory have been reported in different model systems, yet, there is no comprehensive study to characterize all gap genes in any organism. Here, using reverse genetics and neurobehavioural tests, we studied the role of all known genes of the rasgap family in C. elegans in associative learning and memory. We demonstrated that their proteins are implicated in different parts of the learning and memory processes. We show that gap-1 contribute redundantly with gap-3 to the chemosensation of volatile compounds, gap-1 plays a major role in associative learning, while gap-2 and gap-3 are predominantly required for short- and long-term associative memory. Our results also suggest that the C. elegans Ras orthologue let-60 is involved in multiple processes during learning and memory. Thus, we show that the different classes of RasGAP proteins are all involved in cognitive function and their complex interplay ensures the proper formation and storage of novel information in C. elegans.