Search Results (89)

Passion fruit (Passiflora edulis) is an economically important fruit worldwide. However, heat stress severely threatens its production, particularly in tropical and subtropical regions. To elucidate the molecular and metabolic mechanisms underlying heat tolerance, comparative physiological, transcriptomic, and metabolomic analyses were conducted between two yellow passion fruit cultivars: heat-tolerant ‘Summer Queen’ (F2) and heat-sensitive ‘Qinmi 9’ (QM9). Physiological evaluations demonstrated that QM9 exhibited significantly lower heat tolerance than F2, manifesting as severe leaf wilting, impaired photosynthetic efficiency, and elevated reactive oxygen species (ROS) accumulation. F2 exhibited distinct metabolic and transcriptional adaptations under heat stress, particularly in purine metabolism and flavonoid biosynthesis. Metabolites such as glutamine, xanthine, luteoloside, and trifolin were enriched in F2, alongside the upregulation of genes like adenosine kinase (AK), xanthine dehydrogenase (XDH), guanine deaminase (GDA), and flavonoid 3′-hydroxylase (F3′H). Weighted gene co-expression network analysis (WGCNA) highlighted strong associations between these pathways and transcription factors (e.g., MYB, HSF, WRKY), suggesting their pivotal roles in heat adaptation. Exogenous application of xanthine and trifolin markedly enhanced heat tolerance in passion fruit. Furthermore, knockdown of PeGDA and PeXDH markedly altered the heat tolerance of F2. These findings reveal that elevated metabolites in purine metabolism and flavonoid biosynthesis enhance heat tolerance in passion fruit, offering new insights into the molecular mechanisms of heat tolerance and potential targets for breeding climate-resilient passion fruit varieties. Full article

The heat shock protein 70 (Hsp70) family mediates responses to environmental stress in insects. The wheat midge Sitodiplosis mosellana, a worldwide pest, avoids summer and winter temperature extremes by diapause of the third-instar larvae in the soil. To explore the functions of Hsp70s in this process, we characterized two cytoplasmic Hsp70 genes (SmHsp70A1-1 and SmHsp70A1-2) from this insect. Both SmHsp70s contained three signature motifs of the family and lacked introns. Developmental expression profiling revealed maximal SmHsp70A1-1 expression during early larval stages, while the expression of SmHsp70A1-2 was highest in the pupal stages. The expression of SmHsp70A1-1 was significantly upregulated during diapause, particularly during summer and winter, whereas SmHsp70A1-2 showed marked downregulation and dose-dependent induction by 20-hydroxyecdysone (20E). Furthermore, both genes exhibited similar expression patterns in over-summering and over-wintering larvae under thermal stress, with maximal expression at 40 °C and −10 °C, respectively, but were not significantly induced at prolonged extreme temperatures (50 °C or −15 °C). Knockdown of the two SmHsp70 genes by RNA interference (RNAi) significantly increased the susceptibility of the larvae to cold stress. These results suggest the important role of both SmHsp70 genes in diapause-associated stress tolerance and provide crucial insights into the mechanisms underlying thermal adaptation in S. mosellana. Full article

The extensive utilization of amorphous silica nanoparticles (SiNPs) has raised concerns regarding the potential health risks. Previous studies have indicated that SiNPs could trigger both the activation of heat shock proteins (HSPs) and epithelial–mesenchymal transition (EMT) in BEAS-2B cells; however, the underlying mechanisms require further elucidation. This study aimed to investigate how SiNPs activate the heat shock response (HSR) in BEAS-2B cells, which subsequently triggers EMT. Firstly, we observed that SiNPs were internalized by BEAS-2B cells and localized in the endoplasmic reticulum (ER), inducing ER stress. The ER stress led to the activation of SIRT1 by phosphorylation, which enhanced the nuclear transcriptional activity of HSF1 via deacetylation. HSF1 was found to upregulate the levels of HSP70 and HSP27 proteins, which further affected EMT-related genes and, ultimately, induced EMT. Additionally, 4-phenylbutyric acid (4-PBA) inhibited ER stress, which attenuated the SIRT1/HSF1 signaling pathway. The knockdown of SIRT1 and HSF1 using siRNA effectively suppressed the EMT progression. In summary, these results suggested that SiNPs activated the SIRT1/HSF1/HSPs pathway through ER stress, thereby triggering EMT in BEAS-2B cells. The present study identified a novel mechanism of SiNP-induced EMT, which has provided valuable insights for future toxicity studies and risk assessments of SiNPs. Full article

Previous studies revealed that low expression of Selenoprotein S (SELS) could enhance osteogenic differentiation, but the underlying mechanisms remain unclear. In this study, we aimed to elucidate the role of SELS and its transcription-factor-based regulatory mechanism during osteogenic differentiation. In comparison with 12-week-old mice, which represent the stage of stable osteogenic differentiation, 3-week-old mice, representing the active ossification stage, showed significantly higher levels of SELS in the mandible. Transcriptomic analysis revealed that SELS is primarily associated with extracellular matrix organization and collagen biosynthesis during mandibular development. In bone marrow mesenchymal stem cells (BMSCs) with SELS knockdown, SP7 levels were elevated after 7 days of osteogenic induction in vitro. Consistently, immunohistochemical and immunofluorescence staining confirmed increased SP7 expression in the mandibles of 7-week-old Sels knockout mice. Dual-luciferase reporter assays and chromatin immunoprecipitation (ChIP) analysis demonstrated that SP7 directly binds to the heat shock protein 47 (HSP47) promoter and negatively regulates its transcription. Consequently, upregulation of SP7 following SELS knockdown led to downregulation of HSP47 and concurrent upregulation of the SP7 downstream targets, collagen type I alpha 1 chain (COL1A1) and Secreted protein acidic and rich in cysteine (SPARC). SELS expression is upregulated during active osteogenesis. Low expression of SELS regulates osteogenic differentiation in a bidirectional and fine-tuned manner through the SP7–HSP47/COL1A1/SPARC axis. Full article

Molecular chaperones, especially heat shock proteins (HSPs) have vital functions in cells’ responses to stress. Here, we cloned and sequenced the complete complementary DNA encoding HSP90 (MjHSP90) from the shrimp Marsupenaeus japonicus. The MjHSP90 cDNA comprised 3162 bp, including a 2172 bp coding region encoding a 724 amino acid-protein (predicted molecular mass = 83.12 kDa). Homology and phylogenetic analyses showed that MjHSP90 was highly conserved and most homologous to Litopenaeus vannamei HSP90. MjHSP90 is expressed in all tested tissues, with high expression in gill tissue and the hepatopancreas. Cold stress significantly upregulated MjHSP90 expression in the gill and hepatopancreas (p < 0.05). Following RNA interference knockdown of MjHSP90, the cold stress-related death rate of the shrimp increased significantly, accompanied by significantly upregulated expression of apoptosis-related genes Mjcaspase-3 and Mjbcl-2 (p < 0.05) and an increase in the number of apoptotic cells. The results indicated that MjHSP90 might play a pivotal role in the shrimp’s immune response to cold stress. Full article

Myeloid-derived growth factor (MYDGF), named in reference to its secretion from myeloid cells in bone marrow, is a novel protein with anti-apoptotic and tissue-repairing properties. MYDGF is found in various human tissues affected by different diseases. To date, however, MYDGF expression has yet to be reported in the nervous system. Herein, we demonstrate for the first time that MYDGF mRNA levels increased in the zebrafish retina 1 h after optic nerve injury (ONI). MYDGF-producing cells were located in the photoreceptors and infiltrating leukocytic cells. We prepared the retina for MYDGF gene knockdown by performing intraocular injections using either MYDGF-specific morpholino or the CRISPR/Cas9 system. Under these MYDGF-knockdown retinal conditions, anti-apoptotic Bcl-2 mRNA was suppressed; in comparison, apoptotic caspase-3 and inflammatory TNFα mRNA were significantly upregulated in the zebrafish retina after ONI compared to the control. Furthermore, heat shock factor 1 (HSF1) was evidently suppressed under these conditions, leading to a significant number of apoptotic neurons. These findings indicate that MYDGF is a key molecule in the stimulation of neuronal regeneration in the central nervous system. Full article

Enterotoxigenic Escherichia coli (ETEC) leads to severe diarrhea in piglets. Naringenin (Nar), a natural flavonoid compound, is known for its antibacterial and anti-antioxidant properties. However, the protective effects of Nar against ETEC-induced diarrhea have not been reported yet. This study investigated the protective mechanisms of Nar against ETEC infection in porcine intestinal epithelial cells (IPEC-J2). ETEC infection induced oxidative stress and ferroptosis in IPEC-J2 cells by elevating intracellular iron content and ROS accumulation, increasing MDA levels, downregulating SOD activity and GPX4 expression, and upregulating the transcription of CHAC1 and SLC7A11. In contrast, Nar suppressed ETEC-induced ferroptosis of IPEC-J2 cells by inhibiting the SLC7A11/GPX4 pathway. Specifically, Nar mitigated mitochondrial damage, reduced intracellular iron levels and ROS accumulation, and ultimately reversed the oxidative stress. Network pharmacology and molecular docking identified heat-shock protein 90 (HSP90) as a potential target of Nar. Overexpression and knockdown experiments revealed that ETEC-induced ferroptosis was mediated by upregulation of HSP90, while the protective effects of Nar against ETEC-induced ferroptosis were dependent on the downregulation of HSP90. In conclusion, Nar targets host HSP90 to protect IPEC-J2 cells from ferroptosis caused by ETEC infection. This study demonstrates that Nar is a potent antioxidant natural compound with potential for preventing ETEC-induced intestinal damage. Full article

Soybean meal (SBM) is extensively used as a predominant protein source in animal feed. However, raw soybean cannot be directly utilized in animal feed, due to the presence of the Kunitz trypsin inhibitor (KTi) and the Bowman–Birk protease inhibitor (BBi). These antinutritional factors inhibit the digestive enzymes in animals, trypsin and chymotrypsin, resulting in poor animal performance. To inactivate the activity of protease inhibitors, SBM is subjected to heat processing, a procedure that can negatively impact the soybean protein quality. Thus, it would be beneficial to develop soybean varieties with little or no trypsin inhibitors. In this study, we report on the creation of experimental soybean lines with significantly reduced levels of Bowman–Birk protease inhibitors. RNA interference (RNAi) technology was employed to generate several transgenic soybean lines. Some of these BBi knockdown soybean lines showed significantly lower amounts of both trypsin and chymotrypsin inhibitor activities. Western blot analysis revealed the complete absence of BBi in selected RNAi-derived lines. RNA sequencing (RNAseq) analysis demonstrated a drastic reduction in the seed-specific expression of BBi genes in the transgenic soybean lines during seed development. Confocal fluorescence immunolabeling studies showed that the accumulation of BBi was drastically diminished in BBi knockdown lines compared to wild-type soybeans. The absence of BBi in the transgenic soybean did not alter the overall protein, oil, and sulfur amino acid content of the seeds compared to wild-type soybeans. The seed protein from the BBi knockdown lines were more rapidly hydrolyzed by trypsin and chymotrypsin compared to the wild type, indicating that the absence of BBi enhances protein digestibility. Our study suggests that these BBi knockdown lines could be a valuable resource in order for plant breeders to incorporate this trait into commercial soybean cultivars, potentially enabling the use of raw soybeans in animal feed. Full article

Background: Cancer stem cells (CSCs) are a subpopulation of cancer cells known for their self-renewal capacity, tumorigenicity, and resistance to treatment. Toll-like receptor 3 (TLR3) plays a complex role in cancer, exhibiting both pro-apoptotic and pro-tumorigenic effects. This study investigates the pro-tumorigenic role of TLR3, specifically its impact on CSCs in head and neck cancer. Methods: We have investigated Detroit 562, FaDu and SQ20B cell lines, the latter being stably transfected with a plasmid containing inducible shRNA for TLR3, by cultivating them to form tumor spheres in order to study CSCs. Results: Our findings demonstrate that TLR3 activation promotes stemness in head and neck cancer cell lines. This is evidenced by increased tumor sphere formation, promotion of epithelial-to-mesenchymal transition (EMT), upregulated stemness gene expression, and elevated aldehyde dehydrogenase (ALDH) activity. Conditional TLR3 knockdown abolished tumor sphere formation, confirming its important role. Furthermore, TLR3 activation triggers the secretion of damage-associated molecular patterns (DAMPs) into the tumor microenvironment, leading to increased cancer cell migration. This was inhibited by DAMP inhibitors. In patient tissue samples, we observed co-localization of TLR3 with stemness markers CD133 and ALDH1, as well as with heat shock protein 70 (HSP70) and receptor for advanced glycation end products (RAGE). We then explored potential CSC-targeted therapies, initially combining the apoptosis inducer poly (I:C) with DAMP inhibitors and γ-irradiation. While this combination proved effective in adherent cells, it failed to eliminate tumor spheres. Nevertheless, we discovered that proton radiotherapy, particularly when combined with aspirin (HMGB1 inhibitor) and poly (I:C), effectively eliminates CSCs. Conclusions: This novel combination holds promise for the development of new therapeutic strategies for head and neck cancers, particularly given the promising results of proton therapy in treating this disease. Full article

Abiotic stressors threaten honeybee health, jeopardizing pollination services critical to agriculture and biodiversity. Here, we identified the AmVgR gene, which encodes a member of the low-density lipoprotein receptor family, and examined its function in the response of Apis mellifera to adverse abiotic stress. AmVgR exhibited peak expression in adult workers and was significantly upregulated under heat, cold, heavy metal, and pesticide exposure. RNAi-mediated knockdown of AmVgR suppressed antioxidant enzyme activities, elevated the levels of oxidative damage markers, and downregulated antioxidant gene expression. Crucially, AmVgR silencing reduced survival under H₂O₂-induced oxidative stress, indicating its essential role in stress resilience. Our findings highlight AmVgR as a key regulator of antioxidant defense during development and environmental adaptation in Apis mellifera. This study provides mechanistic insights into bee stress physiology and proposes AmVgR as a novel target for enhancing pollinator protection strategies. Further research should elucidate its molecular pathways and translational applications in mitigating abiotic stress impacts. Full article

Small heat shock proteins (sHsps) play crucial roles in organismal adaptation to stress tolerance. Sitodiplosis mosellana, a devastating insect wheat pest, undergoes long obligatory larval diapause to survive temperature extremes during summer and winter. To elucidate the function of sHsps in this process, two sHsp-encoding genes (SmHsp22.2 and SmHsp26.7) were characterized from S. mosellana, and their responsiveness to diapause and thermal stress, as well as their roles in cold stress, was analyzed. Both SmHsp22.2 and SmHsp26.7 possessed the canonical α-crystallin domain and lacked introns. Quantitative PCR indicated significant upregulation of SmHsp22.2 and SmHsp26.7 during diapause, especially in summer and winter. Notably, SmHsp22.2 exhibited higher expression in summer relative to winter, whereas SmHsp26.7 showed the opposite profile. Moreover, short-term heat shock (≥35 °C) in over-summering larvae or cold shock (≤−10 °C) in over-wintering larvae was found to trigger transcriptional upregulation of both genes, while prolonged temperature extremes (i.e., 45–50 °C or −15 °C) did not elicit a comparable response. RNA interference-mediated knockdown of both genes significantly increased the mortality of S. mosellana larvae under cold stress. These findings indicate the importance of both SmHsps in diapause and environmental adaptation in S. mosellana. Full article

Heat stress in dairy cows is aggravated by Global warming, which negatively affects their performance and health, especially high yielding cows are more susceptible to high temperature and humidity in summer. Besides increasing body temperature and reducing feed intake, heat stress also compromises mammary gland function by inducing apoptosis in bovine mammary epithelial cells (BMECs). UFBP1 (Ufm1-binding protein 1) serves as an essential component of ufmylation, is crucial for the preservation of cellular homeostasis. However, little is known about its contribution to heat stress-induced apoptosis in BMECs. Therefore, the present study aimed to elucidate the effect of UFBP1 on heat stress-induced apoptosis through knockdown and overexpression of UFBP1 in BMECs. The results showed that heat stress triggered cell apoptosis (increased apoptosis rate and Bax/Bcl-2 protein expression) and decreased the expression of genes associated with the production of milk fat and protein both in vivo and in vitro studies. Furthermore, UFBP1 silencing aggravated the high-temperature-induced cell damage, and overexpression of UFBP1 attenuated heat stress-induced mitochondrial dysfunction, as evidenced by increased mitochondrial membrane potential (MMP), ATP synthesis and NAD⁺/NADH ratio, as well as the reduced reactive oxygen species (ROS) generation. Importantly, the mitochondrial apoptosis pathway triggered by heat stress was blocked by UFBP1, as indicated by the reduced apoptosis rate and Bax/Bcl-2 protein expression. In addition, UFBP1 restored the expression of milk fat and protein-related genes in heat-stressed BMECs. In conclusion, these findings indicate that UFBP1 may serve as a promising therapeutic target for ameliorating heat stress in dairy cows, thereby providing novel theoretical insights into the mitigation of adverse thermal stress effects on livestock productivity. Full article

Temperature plays a crucial role in shaping the biology of insects. Developmental temperature and acclimation temperatures influence their ability to cope with extreme thermal conditions. This study investigates the effects of developmental temperatures during the pupal stage and adult acclimation temperatures on the thermal tolerance of Tenebrio molitor Linnaeus, 1758. We investigated cold tolerance based on chill-coma recovery time and heat tolerance based on heat knockdown time. Beetles were reared at five developmental temperatures (16, 21, 25, 30 and 35 °C) and later exposed to corresponding adult acclimation temperatures. From developmental temperatures of 21 and 30 °C, the group of beetles was subjected to different temperatures to induce adult acclimation at a different temperature than the developmental temperature. In cold-tolerance tests, beetles reared at lower temperatures showed better recovery from chill coma, while beetles reared at higher temperatures showed greater resistance to heat shock. Adult beetles acclimated to lower temperatures showed better cold tolerance, while those acclimated to higher temperatures performed better in the heat tolerance test. Interestingly, the developmental temperatures during the pupal stage also contributed to resistance, particularly in the heat-tolerance test. However, pupal stage temperatures had no effect on cold-shock resistance, as indicated by chill-coma recovery time. The results could provide insights into the rearing of T. molitor. Full article

Background/Objectives: 17,18-epoxyeicosatetraenoic acid (17,18-EEQ) and 19,20-epoxydocosapentaenoic acid (19,20-EDP) are bioactive metabolites produced from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), respectively, by CYP450s. These metabolites are unstable and quickly metabolized by auto-oxidation, esterification, β-oxidation, or hydrolysis by soluble epoxide hydrolase (sEH). 17,18-EEQ or 19,20-EDP combined with a potent sEH inhibitor t-TUCB differentially activated brown adipose tissue in diet-induced obesity. In the current study, we investigated whether these n-3 epoxy fatty acids with t-TUCB directly promote brown adipocyte differentiation and their thermogenic capacities. Methods: Murine brown preadipocytes were treated with 17,18-EEQ or 19,20-EDP with t-TUCB during and post differentiation. Brown marker protein expression and mitochondrial respiration were measured. In addition, the activation of PPARγ and suppression of NFκB reporter by 17,18-EEQ or 19,20-EDP alone or with t-TUCB were assessed, and the roles of PPARγ were evaluated with PPARγ knockdown and GW9662. Results: 17,18-EEQ or 19,20-EDP with t-TUCB promoted brown adipogenesis and mitochondrial respiration and uncoupling. Moreover, with t-TUCB, both epoxides improved mitochondrial respiration, but only 17,18-EEQ with t-TUCB significantly increased mitochondrial uncoupling (and heat production) in the differentiated adipocytes. PPARγ may be required for the effects of epoxides on differentiation but not on the thermogenic function post differentiation. Conclusions: The results demonstrate that, with t-TUCB, 17,18-EEQ and 19,20-EDP promote brown adipogenesis and mitochondrial respiration and uncoupling. 17,18-EEQ also promotes thermogenesis in differentiated brown adipocytes. Together, the results suggest thermogenic potentials of tested n-3 epoxides, especially 17,18-EEQ with t-TUCB. Translational studies of these n-3 epoxides on human brown adipocyte differentiation and functions are warranted. Full article

Recently, immune checkpoint inhibitors (ICIs) and cabozantinib, a tyrosine kinase inhibitor (TKI), have been used to treat renal cell carcinoma (RCC); the combination of these agents has become a standard treatment for RCC. TKIs generally target vascular endothelial growth factor. However, cabozantinib is characterized by its targeting of MET. Therefore, cabozantinib can be used as a late-line therapy for TKI-resistant RCC. According to data from The Cancer Genome Atlas (TCGA), heat shock transcription factor 4 (HSF4) expression is higher in RCC tissues than in normal renal tissues. HSF4 binds to the MET promoter in colorectal carcinoma to enhance MET expression and promote tumor progression. However, the functional role of HSF4 in RCC is unclear. We performed loss-of-function assays of HSF4, and our results showed that HSF4 knockdown in RCC cells significantly decreased cell functions. Moreover, MET expression was decreased in HSF4-knockdown cells but elevated in sunitinib-resistant RCC cells. The combination of cabozantinib and HSF4 knockdown reduced cell proliferation in sunitinib-resistant cells more than each monotherapy alone. Furthermore, HSF4 knockdown combined with an ICI showed synergistic suppression of tumor growth in vivo. Overall, our strategy involving HSF4 knockdown may enhance the efficacy of existing therapies, such as cabozantinib and ICIs. Full article