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Different types of stress including heat shock may induce genomic instability, due to the derepression and amplification of mobile elements (MEs). It remains unclear, however, whether piRNA-machinery regulating ME expression functions normally under stressful conditions. The aim of this study was to explore the features of piRNA expression after heat shock (HS) exposure inDrosophila melanogaster.We also evaluated functioning of piRNA-machinery in the absence of major stress proteinHsp70in this species. We analyzed the deep sequence data of piRNA expression after HS treatment and demonstrated that it modulates the expression of certain double-stranded germinal piRNA-clusters. Notable, we demonstrated significant changes in piRNA levels targeting a group of MEs after HS only in the strain containing normal set ofhsp70genes. Surprisingly, we failed to detect any correlation between the levels of piRNAs and the transcription of complementary MEs in the studied strains. We propose that modulation of certain piRNA-clusters expression upon HS exposure inD. melanogasteroccurs due to HS-induced altering of chromatin state at certain chromosome regions. [ABSTRACT FROM AUTHOR]

Heat shock protein 70 (HSP70) is activated under stress response. Its involvement in cell protection, including energy metabolism and quality control makes it a promising pharmacological target. A strategy to increase HSP70 levels inside the cells is the application of recombinant HSP70. However, cell permeability and functionality of these exogenously applied proteins inside the cells is still disputable. Here, using fluorescence- labeled HSP70, we have studied permeability and distribution of HSP70 inside primary neurons and astrocytes, and how exogenous HSP70 changes mitochondrial metabolism and mitophagy. We have found that exogenous recombinant HSP70 can penetrate the neurons and astrocytes and distributes in mitochondria, lysosomes and in lesser degree in the endoplasmic reticulum. HSP70 increases mitochondrial membrane potential in control neurons and astrocytes, and in fibroblasts of patients with familial Parkinson´s disease (PD) with PINK1 and LRRK2 mutations. Increased mitochondrial membrane potential was associated with higher mitochondrial ROS production and activation of mitophagy. Importantly, preincubation of the cells with HSP70 protected neurons and astrocytes against cell death in a toxic model of PD induced by rotenone, and in the PINK1 and LRRK2 PD human fibroblasts. Thus, exogenous recombinant HSP70 is cell permeable, and acts as endogenous HSP70 protecting cells in the case of toxic model and familial forms of Parkinson's Disease., (© 2024. The Author(s).)

The phenomenon of paramutation describes the interaction between two alleles, in which one allele initiates inherited epigenetic conversion of another allele without affecting the DNA sequence. Epigenetic transformations due to paramutation are accompanied by the change in DNA and/or histone methylation patterns, affecting gene expression. Studies of paramutation in plants and animals have identified small non-coding RNAs as the main effector molecules required for the initiation of epigenetic changes in gene loci. Due to the fact that small non-coding RNAs can be transmitted across generations, the paramutation effect can be inherited and maintained in a population. In this review, we will systematically analyze examples of paramutation in different living systems described so far, highlighting common and different molecular and genetic aspects of paramutation between organisms, and considering the role of this phenomenon in evolution.

After olfactory bulbectomy, animals are often used as a model of major depression or sporadic Alzheimer's disease and, hence, the status of this model is still disputable. To elucidate the nature of alterations in the expression of the genome after the operation, we analyzed transcriptomes of the cortex, hippocampus, and cerebellum of the olfactory bulbectomized (OBX) mice. Analysis of the functional significance of genes in the brain of OBX mice indicates that the balance of the GABA/glutamatergic systems is disturbed with hyperactivation of the latter in the hippocampus, leading to the development of excitotoxicity and induction of apoptosis in the background of severe mitochondrial dysfunction and astrogliosis. On top of this, the synthesis of neurotrophic factors decreases leading to the disruption of the cytoskeleton of neurons, an increase in the level of intracellular calcium, and the activation of tau protein hyperphosphorylation. Moreover, the acetylcholinergic system is deficient in the background of the hyperactivation of acetylcholinesterase. Importantly, the activity of the dopaminergic, endorphin, and opiate systems in OBX mice decreases, leading to hormonal dysfunction. On the other hand, genes responsible for the regulation of circadian rhythms, cell migration, and innate immunity are activated in OBX animals. All this takes place in the background of a drastic downregulation of ribosomal protein genes in the brain. The obtained results indicate that OBX mice represent a model of Alzheimer's disease with elements of major depression., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Hsp70 is the main molecular chaperone responsible for cellular proteostasis under normal conditions and for restoring the conformation or utilization of proteins damaged by stress. Increased expression of endogenous Hsp70 or administration of exogenous Hsp70 is known to exert neuroprotective effects in models of many neurodegenerative diseases. In this study, we have investigated the effect of exogenous Hsp70 on recovery from peripheral nerve injury in a model of sciatic nerve transection in rats. It was shown that recombinant Hsp70 after being added to the conduit connecting the ends of the nerve at the site of its extended severance, migrates along the nerve into the spinal ganglion and is retained there at least three days. In animals with the addition of recombinant Hsp70 to the conduit, a decrease in apoptosis in the spinal ganglion cells after nerve rupture, an increase in the level of PTEN-induced kinase 1 (PINK1), an increase in markers of nerve tissue regeneration and a decrease in functional deficit were observed compared to control animals. The obtained data indicate the possibility of using recombinant Hsp70 preparations to accelerate the recovery of patients after neurotrauma., Competing Interests: Declaration of Competing Interest The authors have no relevant financial or non-financial interests to disclose., (Copyright © 2023. Published by Elsevier Inc.)

Hsp70 and hydrogen sulfide donors reduce inflammatory processes in human and animal cells. The biological action mediated by Hsp70 and H2S donors (GYY4137 and sodium thiosulfate) depends on their protection kinetics from cell activation by lipopolysaccharides. However, the molecular mechanisms of action of Hsp70 and H2S are not well understood. We studied the effect of human recombinant Hsp70 and H2S donors on the formation of reactive oxygen species and tumor necrosis factor-alpha induced in human cells (THP-1) by lipopolysaccharides. Transcriptomic changes occurring in these cells after LPS administration in combination with GYY4137 pretreatment were investigated. The results we obtained showed that Hsp70 and hydrogen sulfide donors reduce inflammatory processes in cells activated by the action of LPS. Hsp70 and H2S donors differed in the kinetics of the protective action, while hydrogen sulfide donors turned out to be more effective. The role of endocytosis in the mechanisms of protection of cells by H2S and Hsp70 donors from the action of LPS was studied. It has been found that GYY4137 pretreatment of LPS-exposed cells reduces the LPS-induced induction of various pro-inflammatory genes and affects the expression of genes of various intracellular signaling pathways.

Epilepsy is a group of neurological diseases which requires significant economic costs for the treatment and care of patients. The central point of epileptogenesis stems from the failure of synaptic signal transmission mechanisms, leading to excessive synchronous excitation of neurons and characteristic epileptic electroencephalogram activity, in typical cases being manifested as seizures and loss of consciousness. The causes of epilepsy are extremely diverse, which is one of the reasons for the complexity of selecting a treatment regimen for each individual case and the high frequency of pharmacoresistant cases. Therefore, the search for new drugs and methods of epilepsy treatment requires an advanced study of the molecular mechanisms of epileptogenesis. In this regard, the investigation of molecular chaperones as potential mediators of epileptogenesis seems promising because the chaperones are involved in the processing and regulation of the activity of many key proteins directly responsible for the generation of abnormal neuronal excitation in epilepsy. In this review, we try to systematize current data on the role of molecular chaperones in epileptogenesis and discuss the prospects for the use of chemical modulators of various chaperone groups' activity as promising antiepileptic drugs., (© 2023. The Author(s), under exclusive licence to Cell Stress Society International.)

Dysfunction of the RNA-binding protein (RBP) FUS implicated in RNA metabolism can cause amyotrophic lateral sclerosis (ALS) and other neurodegenerative diseases. Mutations affecting FUS nuclear localization can drive RNA splicing defects and stimulate the formation of non-amyloid inclusions in affected neurons. However, the mechanism by which FUS mutations contribute to the development of ALS remains uncertain. Here we describe a pattern of RNA splicing changes in the dynamics of the continuous proteinopathy induced by mislocalized FUS. We show that the decrease in intron retention of FUS-associated transcripts represents the hallmark of the pathogenesis of ALS and is the earliest molecular event in the course of progression of the disease. As FUS aggregation increases, the pattern of RNA splicing changes, becoming more complex, including a decrease in the inclusion of neuron-specific microexons and induction of cryptic exon splicing due to the sequestration of additional RBPs into FUS aggregates. Crucially, the identified features of the pathological splicing pattern are also observed in ALS patients in both sporadic and familial cases. Our data provide evidence that both a loss of nuclear FUS function due to mislocalization and the subsequent cytoplasmic aggregation of mutant protein lead to the disruption of RNA splicing in a multistep fashion during FUS aggregation., (© The Author(s) 2023. Published by Oxford University Press on behalf of Nucleic Acids Research.)

In the present era of global warming and dramatically increased environmental pollution posing a threat to animal life, the understanding and manipulation of organisms' resources of stress tolerance is apparently a question of survival. Heat stress and other forms of stressful factors induce a highly organized response of organisms at the cellular level where heat shock proteins (Hsps) and in particular Hsp70 family of chaperones are among the major players in the protection from the environmental challenge. The present review article summarizes the peculiarities of the Hsp70 family of proteins protective functions being a result of many millions of years of adaptive evolution. It discusses the molecular structure and specific details of hsp70 gene regulation in various organisms, living in diverse climatic zones, with a special emphasis on the protective role of Hsp70 in adverse conditions of the environment. The review discusses the molecular mechanisms underlying Hsp70-specific properties that emerged in the course of adaptation to harsh environmental conditions. This review also includes the data on the anti-inflammatory role of Hsp70 and the involvement of endogenous and recombinant Hsp70 (recHsp70) in proteostatic machinery in various pathologies including neurodegenerative ones such as Alzheimer's and Parkinson's diseases in rodent model organisms and humans in vivo and in vitro . Specifically, the role of Hsp70 as an indicator of disease type and severity and the use of recHsp70 in several pathologies are discussed. The review discusses different roles exhibited by Hsp70 in various diseases including the dual and sometimes antagonistic role of this chaperone in various forms of cancer and viral infection including the SARS-Cov-2 case. Since Hsp70 apparently plays an important role in many diseases and pathologies and has significant therapeutic potential there is a dire need to develop cheap recombinant Hsp70 production and further investigate the interaction of externally supplied and endogenous Hsp70 in chaperonotherapy., Competing Interests: The authors declare no conflict of interest., (© 2023 The Author(s). Published by IMR Press.)

First discovered in maize, paramutation is a phenomenon in which one allele can trigger an epigenetic conversion of an alternate allele. This conversion causes a genetically heterozygous individual to transmit alleles that are functionally the same, in apparent violation of Mendelian segregation. Studies over the past several decades have revealed a strong connection between mechanisms of genome defense against transposable elements by small RNA and the phenomenon of paramutation. For example, a system of paramutation in Drosophila melanogaster has been shown to be mediated by piRNAs, whose primary function is to silence transposable elements in the germline. In this paper, we characterize a second system of piRNA-mediated paramutation-like behavior at the telomere of Drosophila virilis. In Drosophila, telomeres are maintained by arrays of retrotransposons that are regulated by piRNAs. As a result, the telomere and sub-telomeric regions of the chromosome have unique regulatory and chromatin properties. Previous studies have shown that maternally deposited piRNAs derived from a sub-telomeric piRNA cluster can silence the sub-telomeric center divider gene of Drosophila virilis in trans. In this paper, we show that this silencing can also be maintained in the absence of the original silencing allele in a subsequent generation. The precise mechanism of this paramutation-like behavior may be explained by either the production of retrotransposon piRNAs that differ across strains or structural differences in the telomere. Altogether, these results show that the capacity for piRNAs to mediate paramutation in trans may depend on the local chromatin environment and proximity to the uniquely structured telomere regulated by piRNAs. This system promises to provide significant insights into the mechanisms of paramutation.

The gasotransmitter hydrogen sulfide (H 2 S) produced by the transsulfuration pathway (TSP) is an important biological mediator, involved in many physiological and pathological processes in multiple higher organisms, including humans. Cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE) enzymes play a central role in H 2 S production and metabolism. Here, we investigated the role of H 2 S in learning and memory processes by exploring several Drosophila melanogaster strains with single and double deletions of CBS and CSE developed by the CRISPR/Cas9 technique. We monitored the learning and memory parameters of these strains using the mating rejection courtship paradigm and demonstrated that the deletion of the CBS gene, which is expressed predominantly in the central nervous system, and double deletions completely block short- and long-term memory formation in fruit flies. On the other hand, the flies with CSE deletion preserve short- and long-term memory but fail to exhibit long-term memory retention. Transcriptome profiling of the heads of the males from the strains with deletions in Gene Ontology terms revealed a strong down-regulation of many genes involved in learning and memory, reproductive behavior, cognition, and the oxidation-reduction process in all strains with CBS deletion, indicating an important role of the hydrogen sulfide production in these vital processes.

The gasotransmitter hydrogen sulfide (H 2 S) is an important biological mediator, playing an essential role in many physiological and pathological processes. It is produced by transsulfuration - an evolutionarily highly conserved pathway for the metabolism of sulfur-containing amino acids methionine and cysteine. Cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE) enzymes play a central role in cysteine metabolism and H 2 S production. Here we investigated the fitness components (longevity, stress resistance, viability of preimaginal stages, and reproductive function parameters) in D. melanogaster lines containing deletions of the CBS and CSE genes. Surprisingly, in most tests, CSE deletion improved, and CBS worsened the fitness. Lines with deletion of both CBS and CSE demonstrated better stress resistance and longevity than lines with single CBS deletion. At the same time, deletion of both CBS and CSE genes causes more serious disturbances of reproductive function parameters than single CBS deletion. Thus, a complex interaction of H 2 S-producing pathways and cellular stress response in determining the lifespan and fitness components of the whole organism was revealed., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The search for effective neuroprotective agents for the treatment of neurotrauma has always been of great interest to researchers around the world. Extracellular heat shock protein 70 (eHsp70) is considered a promising agent to study, as it has been demonstrated to exert a significant neuroprotective activity against various neurodegenerative diseases. We showed that eHsp70 can penetrate neurons and glial cells when added to the incubation medium, and can accumulate in the nuclei of neurons and satellite glial cells after axotomy. eHsp70 reduces apoptosis and necrosis of the glial cells, but not the neurons. At the same time, co-localization of eHsp70 with p53 protein, one of the key regulators of apoptosis, was noted. eHsp70 reduces the level of the p53 protein apoptosis promoter both in glial cells and in the nuclei and cytoplasm of neurons, which indicates its neuroprotective effect. The ability of eHsp70 to reverse the proapoptotic effect of the p53 activator WR1065 may indicate its ability to regulate p53 activity or its proteosome-dependent degradation.

Audiogenic epilepsy (AE), inherent to several rodent strains is widely studied as a model of generalized convulsive epilepsy. The molecular mechanisms that determine the manifestation of AE are not well understood. In the present work, we compared transcriptomes from the corpora quadrigemina in the midbrain zone, which are crucial for AE development, to identify genes associated with the AE phenotype. Three rat strains without sound exposure were compared: Krushinsky-Molodkina (KM) strain (100% AE-prone); Wistar outbred rat strain (non-AE prone) and "0" strain (partially AE-prone), selected from F2 KM × Wistar hybrids for their lack of AE. The findings showed that the KM strain gene expression profile exhibited a number of characteristics that differed from those of the Wistar and "0" strain profiles. In particular, the KM rats showed increased expression of a number of genes involved in the positive regulation of the MAPK signaling cascade and genes involved in the positive regulation of apoptotic processes. Another characteristic of the KM strain which differed from that of the Wistar and "0" rats was a multi-fold increase in the expression level of the Ttr gene and a significant decrease in the expression of the Msh3 gene. Decreased expression of a number of oxidative phosphorylation-related genes and a few other genes was also identified in the KM strain. Our data confirm the complex multigenic nature of AE inheritance in rodents. A comparison with data obtained from other independently selected AE-prone rodent strains suggests some common causes for the formation of the audiogenic phenotype., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Chuvakova, Funikov, Rezvykh, Davletshin, Evgen’ev, Litvinova, Fedotova, Poletaeva and Garbuz.)

Alzheimer's disease (AD) is a neurodegenerative disease that inevitably results in dementia and death. Currently, there are no pathogenetically grounded methods for the prevention and treatment of AD, and all current treatment regimens are symptomatic and unable to significantly delay the development of dementia. The accumulation of β-amyloid peptide (Aβ), which is a spontaneous, aggregation-prone, and neurotoxic product of the processing of signaling protein APP (Amyloid Precursor Protein), in brain tissues, primarily in the hippocampus and the frontal cortex, was for a long time considered the main cause of neurodegenerative changes in AD. However, attempts to treat AD based on decreasing Aβ production and aggregation did not bring significant clinical results. More and more arguments are arising in favor of the fact that the overproduction of Aβ in most cases of AD is not the initial cause, but a concomitant event of pathological processes in the course of the development of sporadic AD. The concept of neuroinflammation has come to the fore, suggesting that inflammatory responses play the leading role in the initiation and development of AD, both in brain tissue and in the periphery. The hypothesis about the key role of neuroinflammation in the pathogenesis of AD opens up new opportunities in the search for ways to treat and prevent this socially significant disease.

This review describes a brief history of the discovery and studies in Russia and associated countries of the main stress protein (Hsp70) that plays important roles both in the normal function of the cell and body as well as under various stressful stimuli. Research on this protein at the Institute of Molecular Biology (Moscow) began with the elucidation of its adaptive functions at the cellular level and at the level of the whole organism. These studies examined the function of Hsp70 under normal and extreme conditions using a wide range of model and non-model animal species, from Leishmania and Drosophila to camels and humans. These analyses made it possible to elucidate the primary regulations in the evolution and function of heat shock (HS) genes in the studied organisms. Next, we studied the structure and characteristic features of heat shock genes and proteins in species with contrasting habitat temperatures. The systems of Hsp70 expression and isolation we developed using various research objects allowed us to proceed to study the protective properties of human recombinant Hsp70 in normal-aging animal models as well as animal models experiencing sepsis, Alzheimer's disease, and stroke. The results obtained open the prospects of using recombinant Hsp70 for the treatment of various neuropathologies in humans. This review describes the logic and history of investigation of Hsp70 performed by one group of scientists from Engelhardt Institute of Molecular Biology, Russian Academy of Sciences. It was not the goal of this paper to give a comprehensive general picture of other similar studies carried out in Russia during this period., (© 2021. Cell Stress Society International.)

Heat shock proteins (Hsps) represent the most evolutionarily ancient, conserved, and universal system for protecting cells and the whole body from various types of stress. Among Hsps, the group of proteins with a molecular weight of 70 kDa (Hsp70) plays a particularly important role. These proteins are molecular chaperones that restore the native conformation of partially denatured proteins after exposure to proteotoxic forms of stress and are critical for the folding and intracellular trafficking of de novo synthesized proteins under normal conditions. Hsp70s are expressed at high levels in the central nervous system (CNS) of various animals and protect neurons from various types of stress, including heat shock, hypoxia, and toxins. Numerous molecular and behavioral studies have indicated that Hsp70s expressed in the CNS are important for memory formation. These proteins contribute to the folding and transport of synaptic proteins, modulate signaling cascades associated with synaptic activation, and participate in mechanisms of neurotransmitter release. In addition, HSF1, a transcription factor that is activated under stress conditions and mediates Hsps transcription, is also involved in the transcription of genes encoding many synaptic proteins, whose levels are increased in neurons under stress and during memory formation. Thus, stress activates the molecular mechanisms of memory formation, thereby allowing animals to better remember and later avoid potentially dangerous stimuli. Finally, Hsp70 has significant protective potential in neurodegenerative diseases. Increasing the level of endogenous Hsp70 synthesis or injecting exogenous Hsp70 reduces neurodegeneration, stimulates neurogenesis, and restores memory in animal models of ischemia and Alzheimer's disease. These findings allow us to consider recombinant Hsp70 and/or Hsp70 pharmacological inducers as potential drugs for use in the treatment of ischemic injury and neurodegenerative disorders.

Heat shock proteins, in particular Hsp70, play a central role in proteostasis in eukaryotic cells. Due to its chaperone properties, Hsp70 is involved in various processes after stress and under normal physiological conditions. In contrast to mammals and many Diptera species, inducible members of the Hsp70 family in Drosophila are constitutively synthesized at a low level and undergo dramatic induction after temperature elevation or other forms of stress. In the courtship suppression paradigm used in this study, Drosophila males that have been repeatedly rejected by mated females during courtship are less likely than naive males to court other females. Although numerous genes with known function were identified to play important roles in long-term memory, there is, to the best of our knowledge, no direct evidence implicating Hsp70 in this process. To elucidate a possible role of Hsp70 in memory formation, we used D. melanogaster strains containing different hsp70 copy numbers, including strains carrying a deletion of all six hsp70 genes. Our investigations exploring the memory of courtship rejection paradigm demonstrated that a low constitutive level of Hsp70 is apparently required for learning and the formation of short and long-term memories in males. The performed transcriptomic studies demonstrate that males with different hsp70 copy numbers differ significantly in the expression of a few definite groups of genes involved in mating, reproduction, and immunity in response to rejection. Specifically, our analysis reveals several major pathways that depend on the presence of hsp70 in the genome and participate in memory formation and consolidation, including the cAMP signaling cascade.

Pericentromeric heterochromatin in Drosophila generally consists of repetitive DNA, forming the environment associated with gene silencing. Despite the expanding knowledge of the impact of transposable elements (TEs) on the host genome, little is known about the evolution of pericentromeric heterochromatin, its structural composition, and age. During the evolution of the Drosophilidae , hundreds of genes have become embedded within pericentromeric regions yet retained activity. We investigated a pericentromeric heterochromatin fragment found in D. virilis and related species, describing the evolution of genes in this region and the age of TE invasion. Regardless of the heterochromatic environment, the amino acid composition of the genes is under purifying selection. However, the selective pressure affects parts of genes in varying degrees, resulting in expansion of gene introns due to TEs invasion. According to the divergence of TEs, the pericentromeric heterochromatin of the species of virilis group began to form more than 20 million years ago by invasions of retroelements, miniature inverted repeat transposable elements (MITEs), and Helitrons. Importantly, invasions into the heterochromatin continue to occur by TEs that fall under the scope of piRNA silencing. Thus, the pericentromeric heterochromatin, in spite of its ability to induce silencing, has the means for being dynamic, incorporating the regions of active transcription.

Ischaemic stroke is an acute interruption of the blood supply to the brain, which leads to rapid irreversible damage to nerve tissue. Ischaemic stroke is accompanied by the development of neuroinflammation and neurodegeneration observed around the affected brain area. Heat shock protein 70 (Hsp70) facilitates cell survival under a variety of different stress conditions. Hsp70 may be secreted from cells and exhibits cytoprotective activity. This activity most likely occurs by decreasing the levels of several proinflammatory cytokines through interaction with a few receptors specific to the innate immune system. Herein, we demonstrated that intranasal administration of recombinant human Hsp70 shows a significant twofold decrease in the volume of local ischaemia induced by photothrombosis in the mouse prefrontal brain cortex. Our results revealed that intranasal injections of recombinant Hsp70 decreased the apoptosis level in the ischaemic penumbra, stimulated axonogenesis and increased the number of neurons producing synaptophysin. Similarly, in the isolated crayfish stretch receptor, consisting of a single sensory neuron surrounded by the glial envelope, exogenous Hsp70 significantly decreased photoinduced apoptosis and necrosis of glial cells. The obtained data enable one to consider human recombinant Hsp70 as a promising compound that could be translated from the bench into clinical therapies.

The effects of exogenous recombinant human heat shock protein Hsp70 and hydrogen sulfide donor GYY4137 on the mechanisms of endocytosis of lipopolysaccharide (LPS) by human neuroblastoma cells SH-SY5Ywas studied. Hsp70 and GYY4137 have been shown to significantly reduce LPS-induced production of inflammatory mediators by SH-SY5Y cells, including reactive oxygen species, nitric oxide, TNFα, IL-1β, and IL-6. Both the recombinant protein Hsp70 and the hydrogen sulfide donor GYY4137 exhibited significant protective effects; however, the combined use of these agents did not lead to a cumulative effect. It has been shown that pinocytosis, as well as clathrin-, caveolin-, tubulin- and receptor-dependent endocytosis were involved in protecting the cells by both the hydrogen sulfide donor and Hsp70 from LPS-induced production of reactive oxygen species and NO.

Pericentromeric heterochromatin is generally composed of repetitive DNA forming a transcriptionally repressive environment. Dozens of genes were embedded into pericentromeric heterochromatin during evolution of Drosophilidae lineage while retaining activity. However, factors that contribute to insusceptibility of gene loci to transcriptional silencing remain unknown. Here, we find that the promoter region of genes that can be embedded in both euchromatin and heterochromatin exhibits a conserved structure throughout the Drosophila phylogeny and carries motifs for binding of certain chromatin remodeling factors, including insulator proteins. Using ChIP-seq data, we demonstrate that evolutionary gene relocation between euchromatin and pericentric heterochromatin occurred with preservation of sites of insulation of BEAF-32 in evolutionarily distant species, i.e. D. melanogaster and D. virilis. Moreover, promoters of virtually all protein-coding genes located in heterochromatin in D. melanogaster are enriched with insulator proteins BEAF-32, GAF and dCTCF. Applying RNA-seq of a BEAF-32 mutant, we show that the impairment of BEAF-32 function has a complex effect on gene expression in D. melanogaster, affecting even those genes that lack BEAF-32 association in their promoters. We propose that conserved intrinsic properties of genes, such as sites of insulation near the promoter regions, may contribute to adaptation of genes to the heterochromatic environment and, hence, facilitate the evolutionary relocation of genes loci between euchromatin and heterochromatin.

Background: Hydrogen sulfide donors reduce inflammatory signaling in vitro and in vivo. The biological effect mediated by H 2 S donors depends on the kinetics of the gas release from the donor molecule. However, the molecular mechanisms of H 2 S-induced immunomodulation were poorly addressed. Here, we studied the effect of two different hydrogen sulfide (H 2 S)-producing agents on the generation of the LPS-induced inflammatory mediators. Importantly, we investigated the transcriptomic changes that take place in human cells after the LPS challenge, combined with the pretreatment with a slow-releasing H 2 S donor-GYY4137., Methods: We investigated the effects of GYY4137 and sodium hydrosulfide on the release of proinflammatory molecules such as ROS, NO and TNF-α from LPS-treated human SH-SY5Y neuroblastoma and the THP-1 promonocytic cell lines. Transcriptomic and RT-qPCR studies using THP-1 cells were performed to monitor the effects of the GYY4137 on multiple signaling pathways, including various immune-related and proinflammatory genes after combined action of LPS and GYY4137., Results: The GYY4137 and sodium hydrosulfide differed in the ability to reduce the production of the LPS-evoked proinflammatory mediators. The pre-treatment with GYY4137 resulted in a drastic down-regulation of many TNF-α effectors that are induced by LPS treatment in THP-1 cells. Furthermore, GYY4137 pretreatment of LPS-exposed cells ameliorates the LPS-mediated induction of multiple pro-inflammatory genes and decreases expression of immunoproteasome genes. Besides, in these experiments we detected the up-regulation of several important pathways that are inhibited by LPS., Conclusion: Based on the obtained results we believe that our transcriptomic analysis significantly contributes to the understanding of the molecular mechanisms of anti-inflammatory and cytoprotective activity of hydrogen sulfide donors, and highlights their potential against LPS challenges and other forms of inflammation.

Neuroinflammation plays a key role in the pathogenesis of neurodegenerative diseases. Microglial cells are the main immune cells of the central nervous system. On exposure to lipopolysaccharides (LPS, components of the cell wall of Gram-negative enterobacteria), microglia is activated to produce reactive oxygen species (ROS), cytokines, and inflammatory mediators, which may cause neuron death. Exogenous recombinant human heat shock protein 70 (HSP70) was tested for effect on the activation of human microglial and neuroblastoma cells in response to LPS from Escherichia coli. Experiments included cell cultivation separately and transferring the conditioned medium from A-172 microglial cells to SK-N-SH neuroblastoma cells to simulate the effect of microglia treated with LPS and/or HSP70. The levels of ROS, TNFα, and apoptosis in LPS-treated cells were estimated in the presence or absence of HSP70. HSP70 was found to reduce the LPS-induced ROS generation, TNFα production, apoptosis, and necrosis, in both separate cell cultures and neuroblastoma cells grown in the conditioned medium from microglial cells. Signaling pathways involving protein kinases p38MAPK, JNK, and PI3K were demonstrated to play an important role in HSP70-mediated protection of microglial and neuroblastoma cells from LPS-induced apoptosis and ROS production.

Body size reduction, also known as miniaturization, is an important evolutionary process that affects a number of physiological and phenotypic traits and helps animals conquer new ecological niches. However, this process is poorly understood at the molecular level. Here, we report genomic and transcriptomic features of arguably the smallest known insect-the parasitoid wasp, Megaphragma amalphitanum (Hymenoptera: Trichogrammatidae). In contrast to expectations, we find that the genome and transcriptome sizes of this parasitoid wasp are comparable to other members of the Chalcidoidea superfamily. Moreover, compared to other chalcid wasps the gene content of M. amalphitanum is remarkably conserved. Intriguingly, we observed significant changes in M. amalphitanum transposable element dynamics over time, in which an initial burst was followed by suppression of activity, possibly due to a recent reinforcement of the genome defense machinery. Overall, while the M. amalphitanum genomic data reveal certain features that may be linked to the unusual biological properties of this organism, miniaturization is not associated with a large decrease in genome complexity., Competing Interests: The authors have declared that no competing interests exist.

Previously, we demonstrated that species of the Stratiomyidae family exhibit higher tolerance to thermal stress in comparison with that of many representatives of Diptera, including Drosophila species. We hypothesized that species of this group inherited the specific structures of their chaperones from an ancestor of the Stratiomyidae family, and this enabled the descendants to colonize various extreme habitats. To explore this possibility, we cloned and expressed in Escherichia coli copies of the Hsp70 genes from Stratiomys singularior, a typical eurythermal species, and Drosophila melanogaster, for comparison. To investigate the thermal sensitivity of the chaperone function of the inducible 70-kDa heat shock proteins from these species, we used an in vitro refolding luciferase assay. We demonstrated that under conditions of elevated temperature, S. singularior Hsp70 exhibited higher reactivation activity in comparison with D. melanogaster Hsp70 and even human Hsp70. Similarly, S. singularior Hsp70 was significantly more thermostable and showed in vitro refolding activity after preheatment at higher temperatures than D. melanogaster paralog. Thermally induced unfolding experiments using differential scanning calorimetry indicated that Hsp70 from both Diptera species is formed by two domains with different thermal stabilities and that the ATP-binding domain of S. singularior is stable at temperatures 4 degrees higher than that of the D. melanogaster paralog. To the best of our knowledge, this study represents the first report that provides direct experimental data indicating that the evolutionary history of a species may result in adaptive changes in the structures of chaperones to enable them to elicit protective functions at extreme environments.

Heat shock proteins (HSPs) are important factors of protein homeostasis and possess chaperone properties, providing for a folding and intracellular transport of proteins and facilitating the recovery or utilization of proteins partly denatured on exposure to various stress factors. Proteins of the Hsp70 family are the most universal molecular chaperones and interact with the greatest number of protein substrates. Several proteins of the Hsp70 family are released into the extracellular space, where they play an important role in intercellular communications and act as alarmins, or "danger signals," to modulate the immune response. The secreted Hsp70 can additionally act as an effective neuroprotector, increasing the survival of neurons in various proteinopathies, as has been demonstrated in Alzheimer's and Parkinson's disease models. In this regard, recombinant Hsp70 and inducers of endogenous Hsp70 synthesis may be considered as candidate therapeutics with immune-modulating and neuroprotective properties.Heat shock proteins (HSPs) are important factors of protein homeostasis and possess chaperone properties, providing for a folding and intracellular transport of proteins and facilitating the recovery or utilization of proteins partly denatured on exposure to various stress factors. Proteins of the Hsp70 family are the most universal molecular chaperones and interact with the greatest number of protein substrates. Several proteins of the Hsp70 family are released into the extracellular space, where they play an important role in intercellular communications and act as alarmins, or "danger signals," to modulate the immune response. The secreted Hsp70 can additionally act as an effective neuroprotector, increasing the survival of neurons in various proteinopathies, as has been demonstrated in Alzheimer's and Parkinson's disease models. In this regard, recombinant Hsp70 and inducers of endogenous Hsp70 synthesis may be considered as candidate therapeutics with immune-modulating and neuroprotective properties.

The accumulation and aggregation of β-amyloids are major molecular events underlying the progression of Alzheimer's disease. In neural cells, recombinant HSP70 reduces the toxic effect of Aβ and its isomeric forms. Here we describe the proteome of the neuroblastoma cell line after incubation with amyloid peptides Aβ42 and isomerized Asp7 (isoAβ42) without and with human recombinant heat shock protein 70 (HSP70). Incubation of SH-SY5Y cell culture with the synthetic Aβ-peptides leads to a decrease in the levels of several cytoskeleton proteins (e.g., ACTN1, VIME, TPM3) and several chaperonines involved in the folding of actin and tubulin (TCPQ, TCPG, TCPE, TCPB). These changes are accompanied by an increase in the expression of calmodulin and the proteins involved in folding in the endoplasmic reticulum and endoplasmic cell stress response. The presence of exogenous HSP70 has led to an increase in expression of several chaperones and a few other proteins including endogenous HSP70. A combined effect of recombinant HSP70 with Aβ peptides reduced cell apoptosis and significantly decreased the level of tubulin phosphorylation caused by the addition of Aβ peptides.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder that leads to the eventual death of motor neurons. Described cases of familial ALS have emphasized the significance of protein misfolding and aggregation of two functionally related proteins, FUS (fused in sarcoma) and TDP-43, implicated in RNA metabolism. Herein, we performed a comprehensive analysis of the in vivo model of FUS-mediated proteinopathy (ΔFUS(1-359) mice). First, we used the Noldus CatWalk system and confocal microscopy to determine the time of onset of the first clinical symptoms and the appearance of FUS-positive inclusions in the cytoplasm of neuronal cells. Second, we applied RNA-seq to evaluate changes in the gene expression profile encompassing the pre-symptomatic and the symptomatic stages of disease progression in motor neurons and the surrounding microglia of the spinal cord. The resulting data show that FUS-mediated proteinopathy is virtually asymptomatic in terms of both the clinical symptoms and the molecular aspects of neurodegeneration until it reaches the terminal stage of disease progression (120 days from birth). After this time, the pathological process develops very rapidly, resulting in the formation of massive FUS-positive inclusions accompanied by a transcriptional "burst" in the spinal cord cells. Specifically, it manifests in activation of a pro-inflammatory phenotype of microglial cells and malfunction of acetylcholine synapse transmission in motor neurons. Overall, we assume that the highly reproducible course of the pathological process, as well as the described accompanying features, makes ΔFUS(1-359) mice a convenient model for testing potential therapeutics against proteinopathy-induced decay of motor neurons.

Syndromes of hybrid dysgenesis (HD) have been critical for our understanding of the transgenerational maintenance of genome stability by piRNA. HD in D. virilis represents a special case of HD since it includes simultaneous mobilization of a set of TEs that belong to different classes. The standard explanation for HD is that eggs of the responder strains lack an abundant pool of piRNAs corresponding to the asymmetric TE families transmitted solely by sperm. However, there are several strains of D. virilis that lack asymmetric TEs, but exhibit a "neutral" cytotype that confers resistance to HD. To characterize the mechanism of resistance to HD, we performed a comparative analysis of the landscape of ovarian small RNAs in strains that vary in their resistance to HD mediated sterility. We demonstrate that resistance to HD cannot be solely explained by a maternal piRNA pool that matches the assemblage of TEs that likely cause HD. In support of this, we have witnessed a cytotype shift from neutral (N) to susceptible (M) in a strain devoid of all major TEs implicated in HD. This shift occurred in the absence of significant change in TE copy number and expression of piRNAs homologous to asymmetric TEs. Instead, this shift is associated with a change in the chromatin profile of repeat sequences unlikely to be causative of paternal induction. Overall, our data suggest that resistance to TE-mediated sterility during HD may be achieved by mechanisms that are distinct from the canonical syndromes of HD., Competing Interests: The authors have declared that no competing interests exist.

Neuronal dysfunction and loss associated with the accumulation of amyloid-β (Aβ) in the form of extracellular amyloid plaques and hyperphosphorylated tau in the form of intraneuronal neurofibrillary tangles represent key features of Alzheimer's disease (AD). Amyloid plaques found in the brains of AD patients are predominantly composed of Aβ42 and its multiple chemically or structurally modified isoforms. Recently, we demonstrated that Aβ42 with isomerised Asp7 (isoAβ42) which is one of the most abundant Aβ isoform in plaques, exhibited high neurotoxicity in human neuronal cells. Here, we show that, in SH-SY5Y neuroblastoma cells, the administration of synthetic isoAβ42 rather than intact Aβ42 resulted in a significantly higher level of protein phosphorylation, especially the phosphorylation of tau, tubulins, and matrin 3. IsoAβ42 induced a drastic reduction of tau protein levels. Our data demonstrate, for the first time, that isoAβ42, being to date the only known synthetic Aβ species to cause AD-like amyloidogenesis in an animal AD model, induced cell death by disabling structural proteins in a manner characteristic of that observed in the neurons of AD patients. The data emphasize an important role of isoAβ42 in AD progression and provide possible neurotoxicity paths for this particular isoform.

Heat shock proteins (Hsp70s) from two Diptera species that drastically differ in their heat shock response and longevity were investigated. Drosophila melanogaster is characterized by the absence of Hsp70 and other hsps under normal conditions and the dramatic induction of hsp synthesis after temperature elevation. The other Diptera species examined belongs to the Stratiomyidae family (Stratiomys singularior) and exhibits high levels of inducible Hsp70 under normal conditions coupled with a thermotolerant phenotype and much longer lifespan. To evaluate the impact of hsp70 genes on thermotolerance and longevity, we made use of a D. melanogaster strain that lacks all hsp70 genes. We introduced single copies of either S. singularior or D. melanogaster hsp70 into this strain and monitored the obtained transgenic flies in terms of thermotolerance and longevity. We developed transgenic strains containing the S. singularior hsp70 gene under control of a D. melanogaster hsp70 promoter. Although these adult flies did synthesize the corresponding mRNA after heat shock, they were not superior to the flies containing a single copy of D. melanogaster hsp70 in thermotolerance and longevity. By contrast, Stratiomyidae Hsp70 provided significantly higher thermotolerance at the larval stage in comparison with endogenous Hsp70., (© 2017 The Royal Entomological Society.)

Genomic disorders, the syndromes with multiple manifestations, may occur sporadically due to unequal recombination in chromosomal regions with specific architecture. Therefore, each patient may carry an individual structural variant of DNA sequence (SV) with small insertions and deletions (INDELs) sometimes less than 10 bp. The transposable elements of the Tc1/ mariner superfamily are often associated with hotspots for homologous recombination involved in human genetic disorders, such as Williams Beuren Syndromes (WBS) with LIM-kinase 1-dependent cognitive defects. The Drosophila melanogaster mutant agn ts 3 has unusual architecture of the agnostic locus harboring LIMK1 : it is a hotspot of chromosome breaks, ectopic contacts, underreplication, and recombination. Here, we present the analysis of LIMK1 -containing locus sequencing data in agn ts 3 and three D. melanogaster wild-type strains- Canton-S, Berlin , and Oregon-R . We found multiple strain-specific SVs, namely, single base changes and small INDEls. The specific feature of agn ts 3 is 28 bp A/T-rich insertion in intron 1 of LIMK1 and the insertion of mobile S-element from Tc1/ mariner superfamily residing ~460 bp downstream LIMK1 3'UTR. Neither of SVs leads to amino acid substitutions in agn ts 3 LIMK1. However, they apparently affect the nucleosome distribution, non-canonical DNA structure formation and transcriptional factors binding. Interestingly, the overall expression of miRNAs including the biomarkers for human neurological diseases, is drastically reduced in agn ts 3 relative to the wild-type strains. Thus, LIMK1 DNA structure per se , as well as the pronounced changes in total miRNAs profile, probably lead to LIMK1 dysregulation and complex behavioral dysfunctions observed in agn ts 3 making this mutant a simple plausible Drosophila model for WBS.

The heat shock protein 70 (Hsp70, human HSPA1A) plays indispensable roles in cellular stress responses and protein quality control (PQC). In the framework of PQC, it cooperates with the ubiquitin-proteasome system (UPS) to clear damaged and dysfunctional proteins in the cell. Moreover, Hsp70 itself is rapidly degraded following the recovery from stress. It was demonstrated that its fast turnover is mediated via ubiquitination and subsequent degradation by the 26S proteasome. At the same time, the effect of Hsp70 on the functional state of proteasomes has been insufficiently investigated. Here, we characterized the direct effect of recombinant Hsp70 on the activity of 20S and 26S proteasomes and studied Hsp70 degradation by the 20S proteasome in vitro. We have shown that the activity of purified 20S proteasomes is decreased following incubation with recombinant human Hsp70. On the other hand, high concentrations of Hsp70 activated 26S proteasomes. Finally, we obtained evidence that in addition to previously reported ubiquitin-dependent degradation, Hsp70 could be cleaved independent of ubiquitination by the 20S proteasome. The results obtained reveal novel aspects of the interplay between Hsp70 and proteasomes.

Miniaturization is an evolutionary process that is widely represented in both invertebrates and vertebrates. Miniaturization frequently affects not only the size of the organism and its constituent cells, but also changes the genome structure and functioning. The structure of the main heat shock genes (hsp70 and hsp83) was studied in one of the smallest insects, the Megaphragma amalphitanum (Hymenoptera: Trichogrammatidae) parasitic wasp, which is comparable in size with unicellular organisms. An analysis of the sequenced genome has detected six genes that relate to the hsp70 family, some of which are apparently induced upon heat shock. Both induced and constitutively expressed hsp70 genes contain a large number of introns, which is not typical for the genes of this family. Moreover, none of the found genes form clusters, and they are all very heterogeneous (individual copies are only 75-85% identical), which indicates the absence of gene conversion, which provides the identity of genes of this family in Drosophila and other organisms. Two hsp83 genes, one of which contains an intron, have also been found in the M. amalphitanum genome.

Human heat shock protein Hsp70 was experimentally inserted into polyelectrolyte microcapsules. Encapsulated recombinant Hsp70 was studied in terms of its effects on neutrophil apoptosis, the production of reactive oxygen species, and the secretion of tumor necrosis factor alpha by promonocytic THP-1 cells. It was found that encapsulated Hsp70 effectively inhibits neutrophil apoptosis, unlike free exogenous protein used in solution. In THP-1 cells, encapsulated and free Hsp70 reduced LPS-induced tumor necrosis factor alpha production with a similar efficiency. Encapsulated Hsp70 reduces LPS-induced reactive oxygen species production by neutrophils in the course of its release from the microcapsules but not as much as free Hsp70. Thus, the polyelectrolyte microcapsules can be used as containers for the effective delivery of Hsp70 to neutrophils and monocytes to significantly improve the functioning of the innate immune system.

Heat shock genes are the most evolutionarily ancient among the systems responsible for adaptation of organisms to a harsh environment. The encoded proteins (heat shock proteins, Hsps) represent the most important factors of adaptation to adverse environmental conditions. They serve as molecular chaperones, providing protein folding and preventing aggregation of damaged cellular proteins. Structural analysis of the heat shock genes in individuals from both phylogenetically close and very distant taxa made it possible to reveal the basic trends of the heat shock gene organization in the context of adaptation to extreme conditions. Using different model objects and nonmodel species from natural populations, it was demonstrated that modulation of the Hsps expression during adaptation to different environmental conditions could be achieved by changing the number and structural organization of heat shock genes in the genome, as well as the structure of their promoters. It was demonstrated that thermotolerant species were usually characterized by elevated levels of Hsps under normal temperature or by the increase in the synthesis of these proteins in response to heat shock. Analysis of the heat shock genes in phylogenetically distant organisms is of great interest because, on one hand, it contributes to the understanding of the molecular mechanisms of evolution of adaptogenes and, on the other hand, sheds the light on the role of different Hsps families in the development of thermotolerance and the resistance to other stress factors.

Heat shock protein 70, encoded by the HSPA1A gene in humans, is a key component of the machinery that protects neuronal cells from various stress conditions and whose production significantly declines during the course of aging and as a result of several neurodegenerative diseases. Herein, we investigated whether sub-chronic intranasal administration of exogenous Hsp70 (eHsp70) exerts a neuroprotective effect on the temporal cortex and areas of the hippocampus in transgenic 5XFAD mice, a model of Alzheimer's disease. The quantitative analysis of neuronal pathologies in the compared groups, transgenic (Tg) versus non-transgenic (nTg), revealed high level of abnormalities in the brains of transgenic mice. Treatment with human recombinant Hsp70 had profound rejuvenation effect on both neuronal morphology and functional state in the temporal cortex and hippocampal regions in transgenic mice. Hsp70 administration had a smaller, but still significant, effect on the functional state of neurons in non-transgenic mice as well. Using deep sequencing, we identified multiple differentially expressed genes (DEGs) in the hippocampus of transgenic and non-transgenic mice. Furthermore, this analysis demonstrated that eHsp70 administration strongly modulates the spectrum of DEGs in transgenic animals, reverting to a pattern similar to that observed in non-transgenic age-matched mice, which included upregulation of genes responsible for amine transport, transmission of nerve impulses and other pathways that are impaired in 5XFAD mice. Overall, our data indicate that Hsp70 treatment may be an effective therapeutic against old age diseases of the Alzheimer's type.

Experimental evidences indicate that heat-shock protein 70 (HSP70) can serve as a prospective therapeutic agent to treat Alzheimer's disease (AD). It has demonstrated a neuroprotective effect in vivo on mice models of AD. Moreover, HSP70 decreases oxidative stress in neurons induced by amyloid-β (Aβ42) and its more toxic form with isomerized Asp7 (isoAβ42). The dysfunction of Ubiquitin-proteasome system (UPS) is observed in AD. UPS is responsible for the degradation of the majority of cellular proteins and plays an important role in protecting cells from oxidative stress. Here, we have shown that the incubation of human neuroblastoma cells SK-N-SH with isoAβ42 increases the activity of intracellular proteasomes, which are the principal elements of the UPS. On the contrary, the proteasomal activity was decreased in isoAβ42-treated cells in the presence of exogenous HSP70. These results highlight the existence of an interplay between Aβ peptides, proteasomes, and HSP70.

The progress of neurodegeneration in Alzheimer's disease is closely associated with inflammatory processes in the brain tissues induced by beta-amyloid peptides (Aβ). In this paper, we showed that Aβ(1-42) and isoAβ(1-42) in human neuroblastoma cells SK-N-SH and promonocyte THP-1 activated the production of tumor necrosis factor (TNFα). Notably, isoAβ(1-42) had the strongest effect on the increase in the level of TNFα. The addition of recombinant heat-shock protein HSP70 reduces TNFα production induced by Aβ, which leads to a decrease in neuronal cell damage at the organism level.

The production of major human heat shock protein Hsp70 (HSPA1A) in a eukaryotic expression system is needed for testing and possible medical applications. In this study, transgenic mice were produced containing wild-type human Hsp70 allele in the vector providing expression in the milk. The results indicated that human Hsp70 was readily expressed in the transgenic animals but did not apparently preserve its intact structure and, hence, it was not possible to purify the protein using conventional isolation techniques. It was suggested that the protein underwent glycosylation in the process of expression, and this quite common modification for proteins expressed in the milk complicated its isolation. To check this possibility, we mutated all presumptive sites of glycosylation and tested the properties of the resulting modified Hsp70 expressed in E. coli. The investigation demonstrated that the modified protein exhibited all beneficial properties of the wild-type Hsp70 and was even superior to the latter for a few parameters. Based on these results, a transgenic mouse strain was obtained which expressed the modified Hsp70 in milk and which was easy to isolate using ATP columns. Therefore, the developed construct can be explored in various bioreactors for reliable manufacture of high quality, uniform, and reproducible human Hsp70 for possible medical applications including neurodegenerative diseases and cancer., Competing Interests: The authors declare they have no conflict of interest.

The genome expression pattern is strongly modified during the heat shock response (HSR) to form an adaptive state. This may be partly achieved by modulating microRNA levels that control the expression of a great number of genes that are embedded within the gene circuitry. Here, we investigated the cross-talk between two highly conserved and universal house-keeping systems, the HSR and microRNA machinery, in Drosophila melanogaster We demonstrated that pronounced interstrain differences in the microRNA levels are alleviated after heat shock (HS) to form a uniform microRNA pattern. However, individual strains exhibit different patterns of microRNA expression during the course of recovery. Importantly, HS-regulated microRNAs may target functionally similar HS-responsive genes involved in the HSR. Despite the observed general downregulation of primary microRNA precursor expression as well as core microRNA pathway genes after HS, the levels of many mature microRNAs are upregulated. This indicates that the regulation of miRNA expression after HS occurs at transcriptional and post-transcriptional levels. It was also shown that deletion of all hsp70 genes had no significant effect on microRNA biogenesis but might influence the dynamics of microRNA expression during the HSR., (© 2016 The Authors.)

Accumulation of amyloid-β (Aβ) in neurons accompanies Alzheimer's disease progression. In the cytoplasm Aβ influences activity of proteasomes, the multisubunit protein complexes that hydrolyze the majority of intracellular proteins. However, the manner in which Aβ affects the proteolytic activity of proteasomes has not been established. In this study the effect of Aβ42 and Aβ42 with isomerized Asp7 on activity of different forms of proteasomes has been analyzed. It has been shown that Aβ peptides efficiently reduce activity of the 20S proteasomes, but increase activity of the 20S proteasomes capped with the 19S and/or 11S regulators. Modulation of proteasome activity is mainly determined by the C-terminal segment of Aβ (amino acids 17-42). This study demonstrated an important role of proteasome regulators in the interplay between Aβ and the proteasomes.

Heat shock protein 70 (Hsp70) is the major player that underlies adaptive response to hyperthermia in all organisms studied to date. We investigated patterns of Hsp70 expression in larvae of dipteran species collected from natural populations of species belonging to four families from different evolutionary lineages of the order Diptera: Stratiomyidae, Tabanidae, Chironomidae and Ceratopogonidae. All investigated species showed a Hsp70 expression pattern that was different from the pattern in Drosophila. In contrast to Drosophila, all of the species in the families studied were characterized by high constitutive levels of Hsp70, which was more stable than that in Drosophila. When Stratiomyidae Hsp70 proteins were expressed in Drosophila cells, they became as short-lived as the endogenous Hsp70. Interestingly, three species of Ceratopogonidae and a cold-water species of Chironomidae exhibited high constitutive levels of Hsp70 mRNA and high basal levels of Hsp70. Furthermore, two species of Tabanidae were characterized by significant constitutive levels of Hsp70 and highly stable Hsp70 mRNA. In most cases, heat-resistant species were characterized by a higher basal level of Hsp70 than more thermosensitive species. These data suggest that different trends were realized during the evolution of the molecular mechanisms underlying the regulation of the responses of Hsp70 genes to temperature fluctuations in the studied families., (© 2016 The Royal Entomological Society.)

Heat shock proteins including the major stress protein HSP70 support intracellular homeostasis and prevent protein damage after a temperature increase and other stressful environmental stimuli, as well as during aging. We have shown earlier that prolonged administration of recombinant human HSP70 to mice exhibiting Alzheimer's-like neurodegeneration as well as during sepsis reduces the clinical manifestations of these pathologies. Herein, we studied the action of recombinant human HSP70 on young and aged mouse mesenchymal stem cells (MSCs) in culture. The results obtained indicate that HSP70 at concentrations of 2 μg/ml and higher significantly stimulates growth of aged but not young MSCs. A similar effect is produced by application of a mild heat shock (42 °C 5 min) to the cells. Importantly, responses of young and aged MSCs to heat shock treatment of various durations differed drastically, and aged MSCs were significantly more sensitive to higher heat stress exposures than the young cells. Western blotting and protein labeling experiments demonstrated that neither mild heat shock nor exogenous HSP70 administration resulted in significant endogenous HSP70 induction in young and aged MSCs, whereas mild heat shock increased HSC70 levels in aged MSCs. The results of this study suggest that the administration of exogenous HSP70 and the application of mild heat stress may produce a certain "rejuvenating" effect on MSCs and possibly other cell types in vivo, and these interventions may potentially be used for life extension by delaying various manifestations of aging at the molecular and cellular level.

The effect of exogenous heat shock protein HSP70 and lipopolysaccharide (LPS) on the production of reactive oxygen species (ROS), TNFα secretion, and mRNA expression by human neuroblastoma SK-N-SH cells. It was shown that exogenous HSP70 protects neuroblastoma cells from the action of LPS. The protection mechanism of HSP70 includes a reduction in the production of ROS and TNFα and a decrease in the expression of TLR4 and IL-1β mRNA in SK-N-SH cells induced by LPS.