Heat Shock Protein Genes Research Articles

SARS-CoV-2 S, M, and E Structural Glycoproteins Differentially Modulate Endoplasmic Reticulum Stress Responses

We have previously shown that the hepatitis C virus (HCV) E1E2 envelope glycoprotein can regulate HIV-1 long-terminal repeat (LTR) activity through disruption to NF-κB activation. This response is associated with upregulation of the endoplasmic reticulum (ER) stress response pathway. Here, we demonstrate that the SARS-CoV-2 S, M, and E but not the N structural protein can perform similar downmodulation of HIV-1 LTR activation, and in a dose-dependent manner, in both HEK293 and lung BEAS-2B cell lines. This effect is highest with the SARS-CoV-2 Wuhan S strain and decreases over time for the subsequent emerging variants of concern (VOC), with Omicron providing the weakest effect. We developed pseudo-typed viral particle (PVP) viral tools that allowed for the generation of cell lines constitutively expressing the four SARS-CoV-2 structural proteins and utilising the VSV-g envelope protein to deliver the integrated gene construct. Differential gene expression analysis (DGEA) was performed on cells expressing S, E, M, or N to determine cell activation status. Gene expression differences were found in a number of interferon-stimulated genes (ISGs), including IF16, IFIT1, IFIT2, and ISG15, as well as for a number of heat shock protein (HSP) genes, including HSPH1, HSPA6, and HSPBP1, with all four SARS-CoV-2 structural proteins. There were also differences observed in expression patterns of transcription factors, with both SP1 and MAVS upregulated in the presence of S, M, and E but not the N protein. Collectively, the results indicate that gene expression patterns associated with ER stress pathways can be activated by SARS-CoV-2 envelope glycoprotein expression. The results suggest the SARS-CoV-2 infection can modulate an array of cell pathways, resulting in disruption to NF-κB signalling, hence providing alterations to multiple physiological responses of SARS-CoV-2-infected cells.

The Hsf1-sHsp cascade has pan-antiviral activity in mosquito cells

Aedes mosquitoes transmit pathogenic arthropod-borne (arbo) viruses, putting nearly half the world’s population at risk. Blocking virus replication in mosquitoes is a promising approach to prevent arbovirus transmission, the development of which requires in-depth knowledge of virus-host interactions and mosquito immunity. By integrating multi-omics data, we find that heat shock factor 1 (Hsf1) regulates eight small heat shock protein (sHsp) genes within one topologically associated domain in the genome of the Aedes aegypti mosquito. This Hsf1-sHsp cascade acts as an early response against chikungunya virus infection and shows pan-antiviral activity against chikungunya, Sindbis, and dengue virus as well as the insect-specific Agua Salud alphavirus in Ae. aegypti cells and against chikungunya virus and O’nyong-nyong virus in Aedes albopictus and Anopheles gambiae cells, respectively. Our comprehensive in vitro data suggest that Hsf1 could serve as a promising target for the development of novel intervention strategies to limit arbovirus transmission by mosquitoes.

Muscle and Metabolic Genes Are Differentially Expressed During Thermal Acclimation by the Brook Trout Myotome.

Cold-water fishes, such as Brook trout (Salvelinus fontinalis), are being challenged by the consequences of climate change. The ability of these fish to acclimate to warmer environmental conditions is vital to their survival. Acclimation to warmer water may allow brook trout to reduce the metabolic costs of higher temperatures. Previous work has shown that brook trout display a significant thermal acclimation response in their myotomal muscle, with slower contractile properties observed in warm acclimated fish. In this study, gene expression was examined in hatchery brook trout acclimated to a range in temperatures (4, 10 or 20°C). Brook trout displayed variations in gene expression in their myotomal muscle in accordance with acclimation temperature. Genes important for muscle function, cellular metabolism, protein degradation, and stress response showed variation to both warm (20°C) and cold (4°C) acclimation. The warm acclimated fish also showed decreased expression of genes associated with aerobic metabolism and increased expression of genes for heat shock proteins, while the cold acclimated fish showed increased expression of genes associated with lipid metabolism and protein turnover. α-tubulin displayed a close association with thermal acclimation, increasing in expression with acclimation temperature. The patterns of muscle gene expression were the opposite of what was expected. Although warm acclimated fish have previously been shown to display slow muscle contractile properties, this study found that warm acclimation is associated with increased expression of genes for kinetically faster isoforms of important muscle proteins. Collectively, the results demonstrate a robust response to elevated temperature in the hatchery fish greater than 10,000 genes showing differential expression with temperature. These results provide a roadmap for the analysis of the acclimation response of native populations of brook trout encountering climate change.

Gene Expression in Aphelid Zoospores Reveals Their Transcriptional and Translational Activity and Alacrity for Invasion.

In Aphelidium insulamus (Opisthokonta, Aphelida) zoospores, the expression of 7708 genes out of 7802 described genes was detected. For 589 of them, expression levels were shown to be more than 10 times higher than the median level. Among the highly expressed genes with known functions, the largest functional categories were "Cellular Metabolism", "Protein Synthesis", "Cell State Control", and "Nucleic Acid Processing". Unlike fungal zoospores, translational and transcriptional activity was demonstrated for A. insulamus zoospores. With increasing temperature, the expression of many zoospore genes changed dramatically; the expression of heat shock and chaperone protein genes multiplied more than 30 times, indicating the high sensitivity of aphelid zoospores and their response to environmental changes.

Hsf1 is essential for proteotoxic stress response in smyd1b-deficient embryos and fish survival under heat shock.

Molecular chaperones play critical roles in post-translational maintenance in protein homeostasis. Previous studies have shown that loss of Smyd1b function results in defective myofibril organization and dramatic upregulation of heat shock protein gene (hsp) expression in muscle cells of zebrafish embryos. To investigate the molecular mechanisms and functional importance of this stress response, we characterized changes of gene expression in smyd1b knockdown and knockout embryos using RNA-seq. The results showed that the top upregulated genes encode mostly cytosolic heat shock proteins. Co-IP assay revealed that the upregulated cytosolic Hsp70s associate with myosin chaperone UNC45b which is critical for myosin protein folding and sarcomere assembly. Strikingly, several hsp70 genes also display muscle-specific upregulation in response to heat shock-induced stress in zebrafish embryos. To investigate the regulation of hsp gene upregulation and its functional significance in muscle cells, we generated heat shock factor 1 (hsf-/-) knockout zebrafish mutants and analyzed hsp gene expression and muscle phenotype in the smyd1b-/-single and hsf1-/-;smyd1b-/- double-mutant embryos. The results showed that knockout of hsf1 blocked the hsp gene upregulation and worsened the muscle defects in smyd1b-/- mutant embryos. Moreover, we demonstrated that Hsf1 is essential for fish survival under heat shock (HS) conditions. Together, these studies uncover a correlation between Smyd1b deficiency and the Hsf1-activated heat shock response (HSR) in regulating muscle protein homeostasis and myofibril assembly and demonstrate that the Hsf1-mediated hsp gene upregulation is vital for the survival of zebrafish larvae under thermal stress conditions.

Transcriptional dynamics during Heliothis zea nudivirus 1 infection in an ovarian cell line from Helicoverpa zea.

Nudiviruses (family Nudiviridae) are double-stranded DNA viruses that infect various insects and crustaceans. Among them, Heliothis zea nudivirus 1 (HzNV-1) represents the rare case of a lepidopteran nudivirus inducing a sexual pathology. Studies about molecular pathological dynamics of HzNV-1 or other nudiviruses are scarce. Hence, this study aims to provide a transcriptomic profile of HzNV-1 in an ovary-derived cell line of Helicoverpa zea (HZ-AM1), during early (3, 6 and 9 h post-infection) and advanced (12 and 24 h post-infection) stages of infection. Total RNA was extracted from both virus- and mock-infected cells, and RNA-seq analysis was performed to examine both virus and host transcriptional dynamics. Hierarchical clustering was used to categorize viral genes, while differential gene expression analysis was utilized to pinpoint host genes that are significantly affected by the infection. Hierarchical clustering classified the 154 HzNV-1 genes into four temporal phases, with early phases mainly involving transcription and replication genes and later phases including genes for virion assembly. In addition, a novel viral promoter motif was identified in the upstream region of early-expressed genes. Host gene analysis revealed significant upregulation of heat shock protein genes and downregulation of histone genes. The identification of temporal patterns in viral gene expression enhances the molecular understanding of nudivirus pathology, while the identified differentially expressed host genes highlight the key pathways most hijacked by HzNV-1 infection.

Molecular cloning, expression profiling and functional characterization of three small heat shock protein genes in Sogatella furcifera reveals their roles in heat tolerance

Molecular cloning, expression profiling and functional characterization of three small heat shock protein genes in Sogatella furcifera reveals their roles in heat tolerance

Genome-Wide Analysis of the Hsf Gene Family in Rosa chinensis and RcHsf17 Function in Thermotolerance.

Heat shock transcription factors (Hsfs) play an important role in response to high temperatures by binding to the promoter of the heat shock protein gene to promote its expression. As an important ornamental plant, the rose often encounters heat stress during the flowering process. However, there are few studies on the Hsf family in roses (Rosa. chinensis). In the current study, 19 Hsf genes were identified from R. chinensis and grouped into three main subfamilies (A, B, and C) according to their structural characteristics and phylogenetic analysis. The expression patterns of RcHsf genes were detected in different tissues by quantitative real-time PCR. The RcHsf genes exhibited distinct expression patterns at high temperatures, with RcHsf17 having the highest expression level. RcHsf17 was localized in the nucleus and had transcriptional activity. The overexpression of RcHsf17 increased thermotolerance in Arabidopsis, suggesting the potential role of RcHsf17 in the regulation of the high-temperature response. In addition, RcHsf17 overexpressed in Arabidopsis could enhance the response of transgenic Arabidopsis to methyl jasmonate. Collectively, this study identified and screened RcHsfs in response to high temperatures in roses, providing new insights into the functional divergence of RcHsfs and a basis for screening new varieties of rose.

Spatial Genomics Identifies Heat Shock Proteins as Key Molecular Changes Associated to Adipose Periprostatic Space Invasion in Prostate Cancer.

To identify molecular changes during PCa invasion of adipose space using Spatial Transcriptomic Profiling of PCa cells. This study was performed on paired intraprostatic and extraprostatic samples obtained from radical prostatectomy with pT3a pathological stages. Differential gene expression revealed upregulation of heat shock protein genes: DNAJB1, HSPA8, HSP90AA1, HSPA1B, HSPA1A in PCa PanCK+ cells from the adipose periprostatic space. Extraprostatic extension was significantly associated with overexpression of genes involved in metastatic spread (EGR1, OR51E2, SPON2), of aggressiveness ERG negative signature of enhancers of androgen receptor (HOXB13, FOXA1), and of PSMA (FOLH1). They were associated with loss at 6q, 10q, 16q, and gain at 8q24 locus. PCa invasion of adipose EPE induces adaptative process related to heat shock proteins; PCa cells in EPE also present transcriptomics signatures for ERG independent aggressiveness, androgen receptor co-activation, and specific CNV changes.

Effect of Propolis Applied to Goat Kids at Weaning Period on Heat Shock Protein Genes

In recent years, studies on the use of natural and organic additives have gained importance in goat breeding in order to prevent offspring losses and to encourage their growth and development by limiting the use of antibiotics. Especially the weaning period is a stressful period for kids and negative effects such as weight loss, increased susceptibility to viral and bacterial infections may be observed as a result of decreased nutrient intake and utilisation during this period. Considering these disadvantages that occur during the weaning period, it was thought that propolis would increase the potential to protect the health and welfare of kids during the weaning period due to its immunomodulatory, antioxidant, and anti-inflammatory effects. Therefore, we aimed to examine the expression levels of HSP27, HSP60, and HSP70 molecular chaperones that modulate the cellular stress response, which partially express the effects of propolis on weaning stress. Saanen kids were divided into propolis treated (n=10) and control (no propolis treatment; n=10) groups. The propolis-treated group received 0.4 cc propolis once a day for two weeks after weaning. Expression levels were calculated by 2-ΔΔCt using the Pfaffl method and statistical significance levels were determined by Student t test. Blood samples were taken on the day of weaning and the following day to determine the effect of weaning stress on HSP27, HSP60, and HSP70 expression levels. The effect of propolis on weaning stress was examined in samples taken after two weeks of propolis treatment. The expression levels of HSP27 and HSP60 increased by approximately 2-fold during weaning stress, while HSP70 increased by 3.35-fold. When 0.4 cc propolis was applied to kids under weaning stress, a statistically significant downregulation of HSP27 level 1.08-fold, HSP60 level 1.56-fold, and HSP70 level 2.12-fold was obtained at the end of 2 weeks compared to the control group. Our study showed that propolis treatment decreased stress protein levels during weaning stress.

Molecular characterization and polymorphism detection in HSPB6 gene in Sahiwal cattle

The present study was undertaken with the objectives of molecular characterization and detection of genetic polymorphisms in the HSPB6 gene of Sahiwal cattle. A total of 100 Sahiwal cattle maintained at LRC, NDRI, Karnal (Haryana) were included in the study. HSPB6 gene has been mapped on Bos taurus autosome 18 (BTA 18) and spans nearly 2620 bp comprising 3 exons and 2 introns. Four sets of forward and reverse gene-specific oligonucleotide primers of HSPB6 gene were designed using Primer3 software and amplicon size of 529 bp, 460 bp, 670 bp and 502 bp were ascertained. On the basis of comparative sequence analysis, total three polymorphic loci (SNPs) were detected at locus G436A, A2152G and A2417T in HSPB6 gene as compare to Bos taurus (NCBI GenBank AC_000175.1). Out of these three SNPs, two (A2152G and A2417T) were found in 3´-UTR region and third one (G436A) was detected in intronic region 1. However, monomorphic pattern was found in exon 2 of HSPB6 gene in Sahiwal cattle. Further research need be directed to find out the association of allelic variants in major heat shock protein genes to establish markers for the future genetic improvement of livestock through marker assisted selection.

Characterization and functional analysis of small heat shock protein gene HSP20.1 in Bombyx mandarina

Characterization and functional analysis of small heat shock protein gene HSP20.1 in Bombyx mandarina

Identification, Phylogeny, and Expression Profiling of Pineapple Heat Shock Proteins (HSP70) Under Various Abiotic Stresses.

Pineapple (Ananas comosus (L.) Merr.) is an economically significant and delicious tropical fruit. Pineapple commercial production faces severe decline due to abiotic stresses, which affect the development and quality of pineapple fruit. Heat shock protein 70 (HSP70) plays an essential role in abiotic stress tolerance. However, the pineapple HSP70 family identification and expression analysis in response to abiotic stresses has not been studied. To explore the functional role of AcHSP70, different abiotic stress treatments were applied to pineapple cultivar "Bali" seedlings. A total of 21 AcHSP70 members were identified in the pineapple genome. The identified genes were classified into four subfamilies (I-IV) using phylogenetic analysis. The AcHSP70 family is expressed under different stress conditions. Quantitative real time polymerase chain reaction (qRT-PCR) revealed the expression pattern of the AcHSP70 family under cold, drought, salt, and heat stress. The expression level of genes such as AcHSP70-2 increased under heat, cold, and drought stress, while the expression level of genes such as AcHSP70-3 decreased under salt stress. Furthermore, the expression profile of AcHSP70s in different tissues and development stages was analyzed using transcriptome analysis. The HSP70 genes exhibited unique expression patterns in pineapple tissue at different developmental stages. The study therefore provides a list of HSP70 genes with substantial roles in abiotic stress response and valuable information for understanding AcHSP70 functional characteristics during abiotic stress tolerance in pineapple.

Heat alters diverse thermal tolerance mechanisms: An organismal framework for studying climate change effects in a wild bird

Abstract The ability to cope with heat is likely to influence species success amidst climate change. However, heat coping mechanisms are poorly understood in wild endotherms, which are increasingly pushed to their thermoregulatory limits. We take an organismal approach to this problem, unveiling how behavioural and physiological responses may allow success in the face of sublethal heat. We experimentally elevated nest temperatures for 4 h to mimic a future climate scenario (+4.5°C) during a critical period of post‐natal development in tree swallows (Tachycineta bicolor). Heat‐exposed nestlings exhibited marked changes in behaviour, including movement to cooler microclimates in the nest. They panted more and weighed less than controls at the end of the four‐hour heat challenge, suggesting panting‐induced water loss. Physiologically, heat induced high levels of heat shock protein (HSP) gene expression in the blood, alongside widespread transcriptional differences related to antioxidant defences, inflammation and apoptosis. Critically, all nestlings survived the heat challenge, and those exposed to milder heat were more likely to recruit into the breeding population. Early life but sub‐lethal heat may therefore act as a selective event, with the potential to shape population trajectories. Within the population, individuals varied in their physiological response to heat, namely in HSP gene expression, which exhibited higher mean and higher variance in heat‐exposed nestlings than in controls. Heat‐induced HSP levels were unrelated to individual body mass, or among‐nest differences in brood size, temperature, and behavioural thermoregulation. Nest identity explained a significant amount of HSP variation, yet siblings in the same nest differed by an average of ~4‐fold and individuals in the population differed by as much as ~100‐fold in their HSP response. This massive variation extends previous laboratory work in model organisms showing that heat shock proteins may harbour cryptic phenotypic variation. These results shed light on oft‐ignored elements of thermotolerance in wild birds at a critical stage of post‐natal development. By highlighting the scope of heat‐induced HSP gene expression and coupling it with a suite of organismal traits, we provide a framework for future testing of the mechanisms that shape species success in the face of change. Read the free Plain Language Summary for this article on the Journal blog.

Cyst hatching and nauplii vitality of <em>Artemia salina</em> treated with different potencies of Silicea terra

This study is a preliminary step of the Terra Project, a multicentric study aiming to develop methods for improving agriculture and husbandry production through potentized high dilutions (dynamized products), popularly known as “agro-homeopathy.” The present data reflect the characterization of the biological effects of different potencies of Silicea terra on the Artemia salina model concerning cyst hatching, nauplii vitality, and heat shock proteins (HSPs) gene expression, following the standards previously established to study bio-resilience processes [1]. Later, a similar protocol will be tested in rice germination in greenhouses to compose the whole data framework. Herein, the following potencies of Silicea terra were used: 6, 9, 12, 15, 18, 21, 24, 27, and 30cH, all prepared in purified sterile water (PSW). PSW and succussed PSW were used as controls. The potencies and controls were poured into the seawater (10% of the volume) at the moment of cyst seeding using 96-well plates kept at room temperature (average 25oC). All experiment steps were run during the full moon phase due to the high sensitivity of Artemia spp to the circalunar cycle. Two protocols were tested: (a) the constant temperature for 48 hours of incubation and (b) the exposition to one hour of thermic stress (40oC) after 24 hours of incubation. The samples were tested in octuplicate, and each data point was defined as a well containing 5 to 8 cysts. After 24 and 48 hours, the following parameters were evaluated: cyst hatching rate, nauplii vitality (number of live nauplii/total of cysts per well), and nauplii lethality (number of dead nauplii/total of cysts per well). After 48 hours, the remaining biological material was pooled according to each treatment, including a supplementary series of no-treated wells (baseline control), and the mRNA was extracted for further assay of HSP gene expression (HSP40, HSP90, HSP26, and p26). The statistical analysis was made by two-way ANOVA and Tukey test to compare potencies and controls in the function of time, being α=0.05. Lagrangian statistics was used to evaluate the linear time-dependent response in the function of the potencies. Among the different potencies, the 24cH showed a significant reduction in the lethality rate and a significant increase in the hatching and vitality rates when exposed to thermic stress. These data were similar to the baseline standards. The Lagrangian statistics showed a linear relation between time and potencies. The evaluation of HSP gene expression is still in course. This step concludes that Silicea terra 24cH is a good model for the embryo development of Artemia salina and bio-resilience. Both statistical approaches are valuable tools to characterize the mode of action of Silicea terra on biological systems, giving scientific plausibility for its further use in food production chains. Since Artemia salina are non-sentient animals, there is no need for ethical committee approval.

Unveiling the HSF1 Interaction Network: Key Regulators of Its Function in Cancer.

Heat shock factor 1 (HSF1) plays a central role in orchestrating the heat shock response (HSR), leading to the activation of multiple heat shock proteins (HSPs) genes and approximately thousands of other genes involved in various cellular functions. In cancer cells, HSPs play a particular role in coping with the accumulation of damaged proteins resulting from dysregulated translation and post-translational processes. This proteotoxic stress is a hallmark of cancer cells and causes constitutive activation of HSR. Beyond its role in the HSR, HSF1 regulates diverse processes critical for tumor cells, including proliferation, cell death, and drug resistance. Emerging evidence also highlights HSF1's involvement in remodeling the tumor immune microenvironment as well as in the maintenance of cancer stem cells. Consequently, HSF1 has emerged as an attractive therapeutic target, prompting the development of specific HSF1 inhibitors that have progressed to clinical trials. Importantly, HSF1 possesses a broad interactome, forming protein-protein interactions (PPIs) with components of signaling pathways, transcription factors, and chromatin regulators. Many of these interactors modulate HSF1's activity and HSF1-dependent gene expression and are well-recognized targets for cancer therapy. This review summarizes the current knowledge on HSF1 interactions with molecular chaperones, protein kinases, and other regulatory proteins. Understanding the key HSF1 interactions promoting cancer progression, along with identifying factors that disrupt these protein complexes, may offer valuable insights for developing innovative therapeutic strategies against cancer.

Systemic Granulomatosis in the Meagre Argyrosomus regius: Fishing for a Plausible Etiology.

Meagre (Argyrosomus regius) is one of the fast-growing species considered for sustainable aquaculture development along the Mediterranean and Eastern Atlantic coasts. The emergence of Systemic Granulomatosis (SG), a disease marked by multiple granulomas in various tissues, poses a significant challenge in meagre aquaculture. In the current study, we investigate the association of Mycobacterium spp. and SG in offshore aquaculture facilities in Sardinia, Italy. A total of 34 adult seemingly healthy meagre were arbitrarily collected and analyzed, combining histological, microbiological, molecular, metagenomics, and in situ techniques to investigate the presence of pathogens. Ziehl-Neelsen (ZN), periodic acid-schiff (PAS), and Giemsa stains were performed for the detection of acid-fast bacteria, common parasites, and fungi within granulomas, respectively. Granulomas were detected in 91% (31/34) of fish. The affected organs were kidney (88%), liver (47%), heart (41%), intestine (17.6%), and brain (5%). Acid-fast staining, along with Mycobacterium spp. specific quantitative PCR (qPCR), in situ hybridization (ISH) assay, and microbiological analyses showed negative results for the detection of Mycobacterium spp. and other bacteria implicated in granuloma formation. However, PCR amplification and sequencing of the 65-kDa heat shock protein gene revealed the presence of M. chelonae in 13% of both formalin-fixed and frozen liver tissues. Bacterial isolation failed to detect nontuberculous mycobacteria (NTM) and other bacteria typically associated with granulomas. Consistently, the use of an M. chelonae-specific probe in ISH failed to identify this bacterial species in granulomas. Collectively, results do not support the role of M. chelonae in the development of granulomas and suggest rejecting the hypothesis of a potential link between NTM and SG.

High Dietary Zinc Promotes its Optimal Absorption Through Modulation of Key Transporter Genes, SOD1, and HSP70 Expression in Heat-stressed Rats.

Global warming causes heat stress (HS) in animals, impacting nutrient absorption and metabolism. Antioxidant nutrients are crucial for combating HS. This study assessed the impact of increased dietary Zn on nutrient utilization, mineral absorption, and expression of Zn homeostasis regulators, superoxide dismutase-1 (SOD1), and heat shock protein-70 (HSP70) genes in rats under HS. Seventy-two four-week-old Wistar rats were assigned to six groups in a 3×2 factorial design, with three dietary Zn levels (14.6, 32.7, and 48.9 ppm) and two environments, thermo-neutral (TN) and HS, for 42 days, including 14 days of HS exposure. Results showed that HS reduced nutrient intake across Zn levels, though ether extract digestibility increased at 32.7 and 48.9 ppm Zn. Intake, excretion, and apparent daily absorption of Ca, P, Zn, Cu, Mn, and Fe were lower in HS than in TN groups. Hepatic metallothionein-1 (MT1) mRNA expression was downregulated in rats fed 14.6 and 32.7 ppm Zn compared to 48.9 ppm Zn under both environmental conditions. Duodenal Zinc transporter-1 (ZnT1) and Zrt- and Irt-like protein-1 (ZIP1) mRNA expression increased with dietary Zn under TN and HS conditions, respectively. Hepatic SOD1 mRNA expression was significantly downregulated in HS groups, while hepatic HSP70 mRNA expression was significantly upregulated at 48.9 ppm Zn under HS. Present study suggests that, under HS conditions in rats, a higher dietary Zn level of 48.9 ppm may be optimal for improving Zn absorption, enhancing ZIP1, MT1, and HSP70 gene expression, and alleviating the negative effects of HS.

Regulation mechanism of oxidative status, immunity and apoptosis induced by hypoxia and heat exposure via PI3K/Akt signaling pathway in Megalobrama amblycephala

Megalobrama amblycephala, a main herbivorous fish with notable economic benefits in China, often faces serious challenges to its survival and growth due to hypoxia and heat caused by factors such as global warming and intensive aquaculture. To evaluate the combined effects of these stressors, we performed a two-factor crossover test to assess the impacts of simultaneous exposure to hypoxia (2 mg/L) and heat (35 °C) on oxidative stress, immunity and apoptosis in M. amblycephala. These results showed that hypoxia and heat exposure significantly enhanced the expression of oxygen-sensing and heat shock protein (HSP) genes, hypoxia inducible factor 1α (Hif-1α), HIF-prolyl hydroxylase-2 (phd2) and factor inhibiting Hif-1 (fih-1), as well as hsp70 and hsp90α. Furthermore, M. amblycephala suffering from hypoxia and heat exposure exhibited several changes in liver tissues, with the most severe lesions and up-regulation of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) observed in those subjected to simultaneous exposure. Moreover, the combined hypoxia and heat exposure initially triggered an increase in the activities of total antioxidant capacity (T-AOC), superoxide dismutase (SOD) and catalase (CAT), and glutathione (GSH) contents, followed by a reduction, and the accumulation of malondialdehyde (MDA), which induced oxidative stress. This was accompanied by an increase and subsequent reduction in the contents of alkaline phosphatase (AKP), acid phosphatase (ACP), complement component 3 (C3) and C4, immunoglobulin M (IgM), and interferon-γ (IFN-γ) leading to immunosuppression. Additionally, hypoxia and heat exposure up-regulated the expression of antioxidant enzyme genes (nrf2, cu/zn-sod, mn-sod cat, ho-1, pi3k and gpx-1a), inflammatory genes (interleukin il-1β, il-8 and tnf-α), immunity effectors (igm and lyz), as well as apoptosis genes (casp3, casp8, casp9 and p53) and activated p-Akt/Akt, suggesting apoptosis may be linked with oxidative stress and inflammation and mediated through the PI3K/Akt signaling pathway. In short, the combined hypoxia and heat exposure disrupted homoeostasis in M. amblycephala, with a more pronounced detrimental effect than exposure to either stressor alone These results will contribute to understanding the mechanism of combined exposure to hypoxia and heat in fish and provide a fundamental base for fisheries management.

Unlocking marine microbial treasures: new PBP2a-targeted antibiotics elicited by metals and enhanced by RSM-driven transcriptomics and chemoinformatics

Elicitation through abiotic stress, including heavy metals, is a new natural product drug discovery technique. In this research, three compounds 1, 2, and 6, were achieved by triggering zinc and nickel on marine Sphingomonas sp. and Streptomyces sp., which were absent in normal culture. Compound 5 was obtained for the first time from marine bacteria. All compounds showed potent antibacterial activity against Staphylococcus aureus and bactericidal effect at 300 µm, but 6 was more active. The potent compound 6 production was further enhanced through response surface methodology by optimizing the condition consisting of nickel 1 mM ions, 20 mg/L sucrose, 30 mg/L salt and culture time 14 days. Under these conditions, the SM-6 production was enhanced with a yield of 6.3 mg/L, which was absent in the normal culture. Further transcriptome analysis of compound 6 unveiled its antibacterial activity on S. aureus by modulating heat shock protein genes, disrupting protein folding and synthesis, and perturbing cellular redox balance, leading to a comprehensive inhibition of normal bacterial growth. In addition, ADMET has shown that all compounds are safe for cardiac and hepatotoxicity. To determine the anti-bacterial mechanism, all compounds were docked with PBP2a and DNA gyrase enzyme, and TLR-4 protein for predicting vaccine construct, and the best docking score was achieved against PBP2a enzyme with the highest score of −10.2 for compound 6. In-silico cloning was carried out to ensure the expression of proteins generated and were cloned using S.aureus as a host. The simulation studies have shown that both SM-6-PBP2a and TLR-4-PBP2a complex are stable with the system. This study presents a new approach to anti-bacterial drug discovery from microorganisms through heavy metals triggering and enhancing the compound production through response surface methodology.