Negative Transcriptional Regulator Research Articles

Targeting MAPK14 by Lobeline Upregulates Slurp1-Mediated Inhibition of Alternative Activation of TAM and Retards Colorectal Cancer Growth.

Colorectal cancer (CRC) usually creates an immunosuppressive microenvironment, thereby hindering immunotherapy response. Effective treatment options remain elusive. Using scRNA-seq analysis in a tumor-bearing murine model, it is found that lobeline, an alkaloid from the herbal medicine lobelia, promotes polarization of tumor-associated macrophages (TAMs) toward M1-like TAMs while inhibiting their polarization toward M2-like TAMs. Additionally, lobeline upregulates mRNA expression of secreted Ly-6/UPAR-related protein 1 (Slurp1) in cancer cells. The inhibitory effects of lobeline on tumor load and TAM polarization are almost completely eliminated when Slurp1-deficient MC38 cells are subcutaneously injected into mice, suggesting that lobeline exerts an antitumor effect in a Slurp1-dependent manner. Furthermore, using target-responsive accessibility profiling, MAPK14 is identified as the direct target protein of lobeline. Mechanistically, upon binding to MAPK14 in colon cancer cells, lobeline prevents nuclear translocation of MAPK14, resulting in decreased levels of phosphorylated p53. Consequently, negative transcriptional regulation of SLURP1 by p53 is suppressed, leading to enhanced transcription and secretion of SLURP1. Finally, combination therapy using lobeline and anti-PD1 exhibits stronger antitumor effects. Taken together, these findings suggest that remodeling the immunosuppressive microenvironment using small-molecule lobeline may represent a promising therapeutic strategy for CRC.

The Response Regulator OmpR Negatively Controls the Expression of Genes Implicated in Tilimycin and Tilivalline Cytotoxin Production in Klebsiella oxytoca.

Klebsiella oxytoca toxigenic strains represent a critical health threat, mainly due to their link to antibiotic-associated hemorrhagic colitis. This serious condition results from the bacteria's ability to produce tilimycin and tilivalline cytotoxins. Our research highlights the pivotal role of OmpR, a key regulator within the EnvZ/OmpR two-component system, in controlling the virulence factors associated with K. oxytoca. Our findings strongly indicate that OmpR is a repressor of the aroX and npsA genes, the first genes of aroX and NRPS operons, respectively, which are indispensable for producing these enterotoxins. Notably, in the absence of OmpR, we observe a significant increase in cytotoxic effects on Caco-2 cells. These observations identify OmpR as a crucial negative transcription regulator for both operons, effectively managing the release of these cytotoxins. This research deepens our understanding of the mechanisms of toxigenic K. oxytoca and opens promising avenues for targeting OmpR for new therapeutic interventions. By focusing on this innovative approach, we can develop more effective solutions to combat this pressing health challenge, ultimately improving patient outcomes against this pathogen.

Age-dependent increase in apoptosis is associated with dysregulation of miR-92a/Akt/mTOR and NF-κB signaling pathways in male rats.

Brain aging is the leading risk factor for most neurodegenerative diseases and has been linked with high rates of neuron loss. Thus, identifying molecular mechanisms underlying neuron loss and pharmacological modulation may be of great importance for slowing or preventing age-related diseases. Herein, we investigated the roles of miR-92a, Akt, mTOR, and NF-κB in age-associated apoptosis in the hippocampus (a critical structure involved in brain aging) of male rats alone and in combination with prazosin. Twenty-four male Wistar rats were grouped into young control (3-month-old), aged (18-month-old), and aged + prazosin groups (n = 8 for each). Prazosin (1 mg/kg; i.p.) was administered for 4 weeks to aged rats. Apoptosis was detected by TUNEL staining. Western blot for Akt, mTOR, and NF-κB was conducted. miR-92a gene expression was performed by using RT-PCR. The results indicated a marked enhancement of apoptosis in the aging hippocampus. We also detected substantial up-regulation of NF-κB as well as substantial down-regulation of phosphorylated-Akt and mTOR in the aging hippocampus. Moreover, miR-92a gene expression was markedly reduced in the aging hippocampus. Treatment with prazosin significantly suppressed apoptosis and reversed miR-92a gene expression, as well as Akt, mTOR, and NF-κB protein expressions in the aging hippocampus. Considering the NF-κB regulatory role on miRNAs, our results suggest that NF-κB may be a negative transcriptional regulator of miR-92a, which in turn could regulate the Akt/mTOR signaling. In this regard, NF-κB upregulation may mediate the downregulation of miR-92a/Akt/mTOR axis, and thereby contribute to age-related neurodegeneration. This may provide a novel treatment target for delaying or preventing age-related problems.

Heat-tolerant subtropical Porites lutea may be better adapted to future climate change than tropical one in the South China Sea.

Coral reefs are degrading at an accelerating rate owing to climate change. Understanding the heat stress tolerance of corals is vital for their sustainability. However, this tolerance varies substantially geographically, and information regarding coral responses across latitudes is lacking. In this study, we conducted a high temperature (34°C) stress experiment on Porites lutea from tropical Xisha Islands (XS) and subtropical Daya Bay (DY) in the South China Sea (SCS). We compared physiological levels, antioxidant activities, and transcriptome sequencing to explore heat tolerance mechanisms and adaptive potential. At 34°C, both XS and DY corals experienced significant bleaching and the physiological/biochemical index decreased, with XS corals exhibiting greater changes than DY corals. Transcriptome analysis revealed that coral hosts respond to heat stress mainly by boosting metabolic activity. The subtle transcriptional responses of zooxanthellae C15 underscored the host's pivotal role in thermal stress responses. DY coral hosts showed lower bleaching, stronger physiological plasticity, and higher temperature tolerance thresholds than XS, indicating superior heat tolerance. This superiority is linked to negative feedback transcriptional regulation strategies, including active environmental stress response and genetic information damage repair. The differences in thermal adaptability between tropical and subtropical P. lutea in the SCS may be attributed to their genetic differences and native habitat environments, suggesting that subtropical P. lutea may have the potential to adapt to future climate change. This study provides novel insights for predicting the fate of corals at different latitudes in terms of global warming and provides instructive guidance for coral reef ecological restoration.

VprBP regulates osteoclast differentiation via an epigenetic mechanism involving histone H2A phosphorylation

BackgroundBone remodeling is a continuous and balanced process which relies on the dynamic equilibrium between osteoclastic bone resorption and osteoblastic bone formation. During osteoclast differentiation, pro-osteoclastogenic and anti-osteoclastogenic genes are selectively targeted by positive and negative transcription regulators, respectively. VprBP, also known as DCAF1, is a recently identified kinase and plays an important role in driving epigenetic gene silencing and oncogenic transformation. However, nothing is currently known about a possible involvement of VprBP in signaling pathways that regulate other cellular processes.ResultsWe demonstrate that VprBP stimulates RANKL-induced differentiation of osteoclast precursor cells (OCPs) into mature osteoclasts by suppressing the expression of anti-osteoclastogenic genes through phosphorylation of threonine 120 on histone H2A (H2AT120p). H2AT120p is critical for VprBP function, because abrogating VprBP kinase activity toward H2AT120 transcriptionally reactivates anti-osteoclastogenic genes and significantly attenuates osteoclast differentiation. Consistent with this notion, our in vivo studies established the importance of VprBP-mediated H2AT120p in low bone mass phenotypes and osteoporosis caused by overactive osteoclasts.ConclusionsOur data reveal a previously unrecognized function of VprBP in supporting RANKL-induced osteoclast differentiation and the molecular mechanism underlying its action as a negative regulator of anti-osteoclastogenic genes.

Effect of TetR Family Transcriptional Regulator PccD on Phytosterol Metabolism of Mycolicibacterium.

Androstenedione (AD) is an important intermediate for the production of steroidal drugs. The process of transforming phytosterols into AD by Mycolicibacterium is mainly the degradation process of the phytosterol side chain, and the excessive accumulation of propionyl-CoA produced by Mycobacterium will produce toxic effects, which seriously restricts the transformation performance of strains. In this study, Mycolicibacterium sp. LZ2 (Msp) was used as the research object to study the transcription factor PccD of the TetR family, which has the role of propionyl-CoA metabolism regulation. By constructing overexpression and deletion strains of pccD, it was confirmed that pccD had an inhibitory effect on the transcription of propionyl-CoA carboxylase genes (pccA and pccB). Electrophoretic Mobility Shift Assay (EMSA) and DNase I footprint analysis demonstrated that PccD is directly involved in the transcriptional regulation of pccA and pccB and is a negative transcriptional regulator of the pcc operon. In the study of phytosterol transformation, the growth rate and bacterial viability of Msp-ΔpccD were higher than Msp, but the growth of Msp-pccD was inhibited. As a result of testing of intracellular propionyl-CoA levels and AD production yields, it was found that lower propionyl-CoA levels and higher AD production yields were observed in Msp-ΔpccD. The results expand the cognition of propionyl-CoA metabolism regulation and provide a theoretical basis and reference for the rational transformation of phytosterol transformation strains and secondary metabolite synthesis strains with propionyl-CoA as a substrate, which has important research significance.

Abf1 negatively regulates the expression of EPA1 and affects adhesion in Candida glabrata.

Introduction. Adherence is a major virulence trait in Candida glabrata that, in many strains, depends on the EPA (epithelial adhesin) genes, which confer the ability to adhere to epithelial and endothelial cells of the host. The EPA genes are generally found at subtelomeric regions, which makes them subject to subtelomeric silencing. In C. glabrata, subtelomeric silencing depends on different protein complexes, such as silent information regulator and yKu complexes, and other proteins, such as Repressor/activator protein 1 (Rap1) and Abf1. At the EPA1 locus, which encodes the main adhesin Epa1, we previously found at least two cis-acting elements, the protosilencer Sil2126 and the negative element, that contribute to the propagation of silencing from the telomere to the subtelomeric region.Hypothesis. Abf1 binds to the regulatory regions of EPA1 and other regions at the telomere E-R, thereby negatively regulating EPA1 transcription.Aim. To determine whether Abf1 and Rap1 silencing proteins bind to previously identified cis-acting elements on the right telomere of chromosome E (E-R subtelomeric region), resulting in negative regulation of EPA1 transcription and infer Abf1 and Rap1 recognition sites in C. glabrata.Methodology. We used chromatin immunoprecipitation (ChIP) followed by quantitative PCR to determine the binding sites for Abf1 and Rap1 in the intergenic regions between EPA1 and EPA2 and HYR1 and EPA1, and mutants were used to determine the silencing level of the EPA1 promoter region.Results. We found that Abf1 predominantly binds to the EPA1 promoter region, leading to negative regulation of EPA1 expression. Furthermore, the mutant abf1-43, which lacks the last 43 amino acids at its C-terminal end and is defective for subtelomeric silencing, exhibits hyperadherence to epithelial cells in vitro compared to the parental strain, suggesting that EPA1 is derepressed. We also determined the motif-binding sequences for Abf1 and Rap1 in C. glabrata using data from the ChIP assays.Conclusion. Together these data indicate that Abf1 negatively regulates EPA1 expression, leading to decreased adhesion of C. glabrata to epithelial cells.

ETS1 Expression in Diabetic Foot Ulcers: Implications for Fibroblast Phenotype and Wound Healing Through the PP2A/YAP Pathway.

Diabetic foot ulcers (DFUs) are a serious complication of diabetes, characterized by impaired wound healing and high morbidity and mortality risks. While ETS1 is known to influence fibroblast pathological remodeling, its specific role in DFU and fibroblast wound healing remains unclear. Skin tissue samples from DFU patients were categorized by Wagner grades to analyze ETS1 expression. Primary fibroblasts derived from diabetes mellitus wound (DMFBs) were collected from wound margins to test migration ability and analyze cell phenotype by immunofluorescence; they were further treated with siETS1 and the ETS1 inhibitor YK-4-279. Techniques including Western blotting, quantitative Real-Time PCR (qRT-PCR), and immunofluorescence were used to assess the expressionof ETS1, Collagen I, and phenotype in DMFBs. Additionally, the binding sites between human ETS1 and the PP2A promoter were predicted by the UCSC and JASPAR databases. It intended to explore the negative transcriptional regulation of PP2A by ETS1 and its implications in fibroblast function and wound healing. Fibroblasts derived from Wagner Grades II-IV exhibit differences in cell morphology, migratory ability, and phenotype. Our findings indicate a significant upregulation of ETS1 in Wagner III and IV. The downregulation of ETS1 was observed to enhance DMFB migration and increase the expression of Collagen I and α-SMA. These changes suggest a potential mechanism by which PP2A regulates the YAP/Hippo pathway in diabetic wound healing. ETS1 appears to impede the repair processes in DFUs, likely through the negative regulation of PP2A, affecting fibroblast function and wound healing.

Negative regulation of activation-induced cytidine deaminase gene transcription in developing B cells by a PU.1-interacting intronic region

Activation-induced cytidine deaminase (AID, encoded by Aicda) plays a key role in somatic hypermutation and class switch recombination in germinal center B cells. However, off-target effects of AID are implicated in human leukemia and lymphoma. A mouse model of precursor B cell acute lymphoblastic leukemia driven by deletion of the related transcription factors PU.1 and Spi-B revealed C->T transition mutations compatible with being induced by AID. Therefore, we hypothesized that PU.1 negatively regulates Aicda during B cell development. Aicda mRNA transcript levels were increased in leukemia cells and bone marrow pre-B cells lacking PU.1 and/or Spi-B, relative to wild type cells. Using chromatin immunoprecipitation, PU.1 was found to interact with a negative regulatory region (R2–1) within the first intron of Aicda. CRISPR-Cas9-induced mutagenesis of R2–1 in cultured pre-B cells resulted in upregulation of Aicda in response to lipopolysaccharide stimulation. Mutation of the PU.1 interaction site and neighboring sequences resulted in reduced repressive ability of R2–1 in transient transfection analysis followed by luciferase assays. These results show that a PU.1-interacting intronic region negatively regulates Aicda transcription in developing B cells.

Long non-coding RNA SUN2-AS1 acts as a negative regulator of ISGs transcription to promote flavivirus infection

Recent studies highlight the critical involvement of long non-coding RNAs (lncRNAs) in modulating viral replication and immune responses, yet their specific roles in flavivirus infections remain underexplored. Our study has identified lncRNA SUN2-AS1, which is significantly upregulated in response to flavivirus infection in A549, Huh7 cells, and monocyte-differentiated macrophages (MDMs). SUN2-AS1 interacts with the transcription factors NF-κB and STAT1, andits expression is induced by ZIKV RNA via the type I interferon (IFN) pathway. Notably, SUN2-AS1 enhances the infection of flaviviruses, including ZIKV, DENV2, and JEV, while showing no effect on VSV or HSV-1 infections. Mechanistically, SUN2-AS1 exerts a proviral effect by inhibiting the transcription of interferon-stimulated genes (ISGs). These findings uncover a novel mechanism by which lncRNAs facilitate flavivirus propagation and highlight SUN2-AS1 as a potential target for antiviral therapeutic strategies.

SVA Regulation of Transposable Element Clustered Transcription within the Major Histocompatibility Complex Genomic Class II Region of the Parkinson's Progression Markers Initiative.

SINE-VNTR-Alu (SVA) retrotransposons can regulate expression quantitative trait loci (eQTL) of coding and noncoding genes including transposable elements (TEs) distributed throughout the human genome. Previously, we reported that expressed SVAs and human leucocyte antigen (HLA) class II genotypes on chromosome 6 were associated significantly with Parkinson's disease (PD). Here, our aim was to follow-up our previous study and evaluate the SVA associations and their regulatory effects on the transcription of TEs within the HLA class II genomic region. We reanalyzed the transcriptome data of peripheral blood cells from the Parkinson's Progression Markers Initiative (PPMI) for 1530 subjects for TE and gene RNAs with publicly available computing packages. Four structurally polymorphic SVAs regulate the transcription of 20 distinct clusters of 235 TE loci represented by LINES (37%), SINES (28%), LTR/ERVs (23%), and ancient transposon DNA elements (12%) that are located in close proximity to HLA genes. The transcribed TEs were mostly short length, with an average size of 389 nucleotides. The numbers, types and profiles of positive and negative regulation of TE transcription varied markedly between the four regulatory SVAs. The expressed SVA and TE RNAs in blood cells appear to be enhancer-like elements that are coordinated differentially in the regulation of HLA class II genes. Future work on the mechanisms underlying their regulation and potential impact is essential for elucidating their roles in normal cellular processes and disease pathogenesis.

IFNh and IRF9 influence the transcription of MHCII mediated by IFNγ to maintain immune balance in sea perch lateolabrax japonicus

The major histocompatibility complex class II (MHCII) molecules are crucial elements of the adaptive immune system, essential for orchestrating immune responses against foreign pathogens. However, excessive expression of MHCII can disrupt normal physiological functions. Therefore, the host employs various mechanisms to regulate MHCII expression and maintain immune homeostasis. Despite this importance, limited studies have explored the negative regulation of MHCII transcription in bony fish. In this study, we found that interferon h (IFNh), a subtype of type I IFN in sea perch Lateolabrax japonicus, could inhibit the activation of IFNγ induced-MHCII expression by modulating the transcription of the class II major histocompatibility complex transactivator (CIITA). Transcriptome analysis revealed 57 up-regulated and 69 down-regulated genes in cells treated with both IFNγ and IFNh compared to those treated with IFNγ alone. To maintain cellular homeostasis, interferon regulatory factor 9 (IRF9) was up-regulated following IFNγ stimulation, thereby preventing MHCII overexpression. Mechanistically, IRF9 bound to the CIITA promoter and suppressed its expression activated by IRF1. Furthermore, IRF9 inhibited the promoter activity of both MHCII-α and MHCII-β induced by CIITA. Our findings highlight the roles of IFNh and IRF9 as suppressors regulating MHCII expression at different hierarchical levels. This study provides insights into the intricate regulation of antigen presentation and the foundation for further exploration of the interaction mechanisms between aquatic virus and fish.

Negative Regulators, TUP1, NRG1, and TOR1: Possible Molecular Targets of Antibiofilm Activity of Nano-Fe3 O4 in Candida albicans

Background: Candida albicans is an opportunistic pathobiont that manifests as candidiasis. Drug-resistant biofilms hinder current treatment of candidiasis. The morphological control of filamentous growth and biofilm formation is vital for the pathogenicity of C. albicans. This study aimed to investigate the antifungal activity of magnetic iron oxide nanoparticles (nano-Fe3 O4 ) against C. albicans, their ability to inhibit pre-formed biofilms, and to examine the expression levels of negative regulators, transcriptional repressors thymidine uptake 1 (TUP1), the negative transcriptional regulator of glucose repressed genes (NRG1), and target of rapamycin (TOR1) in C. albicans pre-formed biofilms after treatment with nano-Fe3 O4 . Methods: This study examines the antifungal activity of nano-Fe3 O4 against C. albicans, its ability to inhibit pre-formed biofilms, and investigates the expression levels of negative regulators, TUP1, NRG1, and TOR1 in C. albicans pre-formed biofilms after treatment with nano-Fe3 O4 . Results: Nano-Fe3 O4 at concentrations of 2× minimum inhibitory concentration (MIC), 1× MIC, and ½× MIC showed significant inhibitory effects on C. albicans pre-formed biofilm formation by 2,3-bis (2-methoxy-4-nitro-5 sulfophenyl)-5-[(phenylamino) carbonyl])-2H-tetrazolium hydroxide (XTT), crystal violet staining and light field microscopy with a MIC of 50 μg/mL. Gene expression profiling showed that nano-Fe3 O4 upregulates targets TUP1, NRG1, and TOR1 in C. albicans pre-formed biofilms. Conclusion: Our results suggest that nano-Fe3 O4 diminishes pre-formed biofilms and may subsequently reduce the pathogenicity of C. albicans, which can be responsible for biofilm-associated infections. TUP1, NRG1, and TOR1 may be possible molecular targets in C. albicans pre-formed biofilms after treatment with nano-Fe3 O4.

Long non-coding RNA SIX1-1 promotes proliferation of cervical cancer cells via negative transcriptional regulation of RASD1.

Cervical cancer poses a significant health burden for women globally, and the rapid proliferation of cervical cancer cells greatly worsens patient prognosis. Long non-coding RNAs (lncRNAs) play a crucial role in regulating tumor cell proliferation. However, the involvement of lncRNAs in cervical cancer cell proliferation remains unclear. In this study, we investigated the lncRNA SIX1-1, which was found to be upregulated in cervical cancer tissues and cell lines. Functional assays revealed that knockdown of SIX1-1 inhibited cell proliferation in vitro and reduced tumor growth in vivo. Mechanistically, SIX1-1 was predominantly localized in the nucleus and could bind with DNMT1 protein. The expression of SIX1-1 enhanced the interaction of DNMT1 with RASD1 promoter, leading to the methylation of the promoter and decreased mRNA transcription. Then RASD1 downregulation activated the cAMP/PKA/CREB signaling pathway, promoting cell proliferation. Rescue experiments showed that knockdown of RASD1 restored the inhibited cell proliferation caused by decreased expression of SIX1-1, indicating that RASD1 acted as the functional mediator of SIX1-1. In conclusion, SIX1-1 promoted cervical cancer cell proliferation by modulating RASD1 expression. This suggests that targeting the SIX1-1/RASD1 axis could be a potential antitumor strategy for cervical cancer.

Negative regulation of HDAC3 transcription by histone acetyltransferase TIP60 in colon cancer

BackgroundColon cancer is the third most common cancer globally. The expression of histone deacetylase 3 (HDAC3) is upregulated, whereas the expression of tat interactive protein, 60 kDa (TIP60) is downregulated in colon cancer. However, the relationship between HDAC3 and TIP60 in colon cancer has not been clearly elucidated.ObjectiveWe investigated whether TIP60 could regulate the expression of HDAC3 and suppress colon cancer cell proliferation.MethodsRNA sequencing data (GSE108834) showed that HDAC3 expression was regulated by TIP60. Subsequently, we generated TIP60-knockdown HCT116 cells and examined the expression of HDAC3 by western blotting and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). We examined the expression pattern of HDAC3 in various cancers using publicly available datasets. The promoter activity of HDAC3 was validated using a dual-luciferase assay, and transcription factors binding to HDAC3 were identified using GeneCards and Promo databases, followed by validation using chromatin immunoprecipitation-quantitative polymerase chain reaction. Cell proliferation and apoptosis were assessed using colony formation assays and fluorescence-activated cell sorting analysis of HCT116 cell lines.ResultsIn response to TIP60 knockdown, the expression level and promoter activity of HDAC3 increased. Conversely, when HDAC3 was downregulated by overexpression of TIP60, proliferation of HCT116 cells was inhibited and apoptosis was promoted.ConclusionTIP60 plays a crucial role in the regulation of HDAC3 transcription, thereby influencing cell proliferation and apoptosis in colon cancer. Consequently, TIP60 may function as a tumor suppressor by inhibiting HDAC3 expression in colon cancer cells.

Suppression of TNF-α activity by immobilization rescues Mkx expression and attenuates tendon ossification in a mouse Achilles tenotomy model.

Traumatic heterotopic ossification is a condition in which extraskeletal bone formation occurs in soft tissues after injury. It most commonly occurs in patients who had major orthopedic surgery and in those with severe extremity injuries. The lesion causes local pain and can impair motor function of the affected limb, but there is currently no established prophylaxis or treatment for this condition. In this study, we show that immobilization at an early stage of the inflammatory response after injury can attenuate ossification formation in a murine Achilles tenotomy model. Gene expression analysis revealed a decrease in the expression of Tnf and an increase in the expression of Mkx, which encodes one of the master regulators of tendon differentiation, Mohawk. Notably, we found that TNF-α suppressed the expression of Mkx transcripts and accelerated the osteogenic differentiation of tendon-derived mesenchymal stem cells (MSCs), suggesting that TNF-α acts as a negative regulator of Mkx transcription. Consistent with these findings, pharmaceutical inhibition of TNF-α increased the expression of Mkx transcripts and suppressed bone formation in this mouse model. These findings reveal the previously unrecognized involvement of TNF-α in regulating tendon MSC fate through suppression of Mkx expression and suggest that TNF-α is a potential target for preventing traumatic heterotopic ossification.

Inhibition of Hmbox1 Promotes Cardiomyocyte Survival and Glucose Metabolism Through Gck Activation in Ischemia/Reperfusion Injury.

Exercise-induced physiological cardiac growth regulators may protect the heart from ischemia/reperfusion (I/R) injury. Homeobox-containing 1 (Hmbox1), a homeobox family member, has been identified as a putative transcriptional repressor and is downregulated in the exercised heart. However, its roles in exercise-induced physiological cardiac growth and its potential protective effects against cardiac I/R injury remain largely unexplored. We studied the function of Hmbox1 in exercise-induced physiological cardiac growth in mice after 4 weeks of swimming exercise. Hmbox1 expression was then evaluated in human heart samples from deceased patients with myocardial infarction and in the animal cardiac I/R injury model. Its role in cardiac I/R injury was examined in mice with adeno-associated virus 9 (AAV9) vector-mediated Hmbox1 knockdown and in those with cardiac myocyte-specific Hmbox1 ablation. We performed RNA sequencing, promoter prediction, and binding assays and identified glucokinase (Gck) as a downstream effector of Hmbox1. The effects of Hmbox1 together with Gck were examined in cardiomyocytes to evaluate their cell size, proliferation, apoptosis, mitochondrial respiration, and glycolysis. The function of upstream regulator of Hmbox1, ETS1, was investigated through ETS1 overexpression in cardiac I/R mice in vivo. We demonstrated that Hmbox1 downregulation was required for exercise-induced physiological cardiac growth. Inhibition of Hmbox1 increased cardiomyocyte size in isolated neonatal rat cardiomyocytes and human embryonic stem cell-derived cardiomyocytes but did not affect cardiomyocyte proliferation. Under pathological conditions, Hmbox1 was upregulated in both human and animal postinfarct cardiac tissues. Furthermore, both cardiac myocyte-specific Hmbox1 knockout and AAV9-mediated Hmbox1 knockdown protected against cardiac I/R injury and heart failure. Therapeutic effects were observed when sh-Hmbox1 AAV9 was administered after I/R injury. Inhibition of Hmbox1 activated the Akt/mTOR/P70S6K pathway and transcriptionally upregulated Gck, leading to reduced apoptosis and improved mitochondrial respiration and glycolysis in cardiomyocytes. ETS1 functioned as an upstream negative regulator of Hmbox1 transcription, and its overexpression was protective against cardiac I/R injury. Our studies unravel a new role for the transcriptional repressor Hmbox1 in exercise-induced physiological cardiac growth. They also highlight the therapeutic potential of targeting Hmbox1 to improve myocardial survival and glucose metabolism after I/R injury.

Hypoxia treatment and resistance training alters microRNA profiling in rats skeletal muscle

MicroRNAs (miRNAs) may play a crucial regulatory role in the process of muscle atrophy induced by high-altitude hypoxia and its amelioration through resistance training. However, research in this aspect is still lacking. Therefore, this study aimed to employ miRNA microarray analysis to investigate the expression profile of miRNAs in skeletal muscle from an animal model of hypoxia-induced muscle atrophy and resistance training aimed at mitigating muscle atrophy. The study utilized a simulated hypoxic environment (oxygen concentration at 11.2%) to induce muscle atrophy and established a rat model of resistance training using ladder climbing, with a total intervention period of 4 weeks. The miRNA expression profile revealed 9 differentially expressed miRNAs influenced by hypoxia (e.g., miR-341, miR-32-5p, miR-465-5p) and 14 differentially expressed miRNAs influenced by resistance training under hypoxic conditions (e.g., miR-338-5p, miR-203a-3p, miR-92b-3p) (∣log2(FC)∣ ≥ 1.5, p < 0.05). The differentially expressed miRNAs were found to target genes involved in muscle protein synthesis and degradation (such as Utrn, mdm2, eIF4E), biological processes (such as negative regulation of transcription from RNA polymerase II promoter, regulation of transcription, DNA-dependent), and signaling pathways (such as Wnt signaling pathway, MAPK signaling pathway, ubiquitin-mediated proteolysis, mTOR signaling pathway). This study provides a foundation for understanding and further exploring the molecular mechanisms underlying hypoxia-induced rats muscle atrophy and the mitigation of atrophy through resistance training.

Computational Analysis of Single Nucleotide Polymorphisms in Human HIC1 Gene.

Background A putative tumor suppressor gene called HIC1 (hypermethylated in cancer) is situated at 17p13.3, a locus where the allelic loss occurs often in human malignancies, including breast cancer. Hypermethylated in cancer 1 protein is a protein that in humans is encoded by the HIC1 gene and it's aHomo sapiens(Human). This gene functions as a growth regulatory and tumor repressor gene. The molecular function of HIC1 gene includes DNA-binding transcription factor activity, sequence-specific DNA binding, DNA binding, histone deacetylase binding, protein binding, metal ion binding, nucleic acid binding, DNA-binding transcription repressor activity, RNA polymerase II-specific, DNA-binding transcription factor activity, RNA polymerase II-specific. The biological process of HIC1 gene includes multicellular organism development, negative regulation of Wnt signaling pathway, positive regulation of DNA damage response, signal transduction by p53 class mediator regulation of transcription, DNA-templated, negative regulation of transcription by RNA polymerase II, Wnt signaling pathway, transcription, DNA-templated, intrinsic apoptotic signaling pathway in response to DNA damage, cellular response to DNA damage stimulus. The study aimed to predict the stability and structure of the protein that will arise from single nucleotide polymorphisms (SNPs) in the human HIC1 gene. Methodology To investigate the possible negative effects associated with these SNPs, bioinformatic analysis is typically essential. The following tools were employed for forecasting harmful SNPs: scale-invariant feature transform (SIFT), Protein Analysis Through Evolutionary Relationships (PANTHER), nonsynonymous SNP by Protein Variation Effect Analyzer (PROVEAN), and nonsynonymous SNP by Single Nucleotide Polymorphism Annotation Platform (SNAP). Results The present study identified a total of 36 SNPs using the SIFT approach, which were shown to have functional significance. Twenty-six were determined to be tolerable, whereas 10 were shown to be detrimental. Out of 20 SNPs, seven (P370A, P646S, R654P, A476T, S400S, D666N, D7V) SNPs were predicted as "Possibly damaging" and seven (L9F, G468R, G490R, L482R, S12W, G489D, S12P) were identified as "probably benign", and six (R725G, G620S, A56V, E463D, D394N, L338V) were identified as "probably damaging" according to the predictions made by PANTHER tools. The majority of the pixels on the strip were red, indicating that the gene changes may have dangerous consequences. These results highlight the need for more research to fully comprehend how these mutations affect the hic1 protein's function, which is essential for the emergence of different types of cancer. Conclusion The current research has provided us with essential information about how SNPs might be used as a diagnostic marker for cancer, given that SNPs may be candidates for cellular changes caused by mutations linked to cancer.

POLR3A-mutated Wiedemann-Rautenstrauch fibroblasts display differential profile of intron retention and expression of TP53 isoforms

BACKGROUND: Wiedemann-Rautenstrauch Syndrome (WRS) is a neonatal progeroid syndrome for which biallelic pathogenic variants in RNA polymerase III subunit A (POLR3A) have recently been described. POLR3 is a 17 subunits protein complex responsible for the transcription of short RNAs including all the transfer RNAs (tRNAs), the 5 S subunit of ribosomal RNA, the short nuclear RNA U6, among other regulatory RNAs. OBJECTIVE: We aim to evaluate the impact of POLR3A pathogenic variants on the relative expression of the short nuclear RNA U6 and on the differential profile of intron retention RNA U6, p53 isoforms and in fibroblasts derived from patients with WRS and control fibroblasts. METHODS: RNA was extracted by the TRIzol method; intron retention analysis was performed by using IRFinder from an mRNA sequencing (RNA-Seq) platform; P53 isoforms, short nuclear RNA U6 and additional genes related to cell senescence were measured by RT-PCR. RESULTS: No significant differences were found in the percentage of intron retention (control: 7.8%, WRS1 : 6.3%and WRS2 : 8.14%). Genes showing higher intron retention profile in both groups were mainly related to RNA binding pathways, cell cycle regulation, positive regulation of transcription, positive regulation of inflammatory pathways, negative regulation of apoptosis, RNA transcription, mitochondria, and regulation of translation initiation. However, in WRS fibroblasts the genes with more intron retention were those related to the immune response and mitochondrial function; while in control those related to the response to oxidative stress had the most introns retained. WRS1 showed higher expression of short nuclear RNA U6 compared to control and WRS2; while both WRS cells showed higher expression of p53β and lower percentage of Δ133p63α, consistent with a higher expression of the cellular senescence markers p16 and p21. CONCLUSIONS: These results demonstrated the important role of POLR3A in the maintenance of cellular homeostasis and highlight its potential role in cell senescence in WRS.