Inhibitory Role Research Articles

Significant association of miRNA 34a with BRCA1 expression in pancreatic ductal adenocarcinoma: an insight on miRNA regulatory pathways in the Pakistani population

BackgroundPancreatic Ductal Adenocarcinoma (PDAC) is among the most aggressive cancers, characterized by high mortality rates. Studies on various cancers across the globe indicate that regulatory miRNAs play a vital role in cellular signaling. However, the expression and interactions of these miRNAs in the Pakistani patients with PDAC is yet to be explored. Here, we aim to investigate a panel of four regulatory miRNAs (miRNA 34a, 30b, 142 and 137) in PDAC and their interaction with selected target proteins in the signaling pathway (KRAS, p53, BRCA1, APC).MethodsWe conducted a study on 109 PDAC patients to analyze the selected miRNAs and protein targets. Formalin Fixed Paraffin Embedded (FFPE) tumor samples were obtained from the hospital’s department of histopathology. After confirmation of diagnosis and appropriate tumor content, tissues were processed for RNA extraction. Based on the acceptable quality and quantity of RNA, 43 samples were proceeded for qRT-PCR. Relative expression of the miRNAs was determined through 2−[ΔΔCt] method. Further, FFPE tumor blocks were used to perform tissue sectioning followed by immunohistochemistry experiments. Stained slides were scored independently by two pathologists according to set criteria.ResultsExpression profiles revealed that miRNA 34a, 30b, and 142 showed high expression in approximately 69–70% of cases, while miRNA 137 had a lower high expression frequency (53.4%). Among protein biomarkers, KRAS, BRCA1, and APC were predominantly expressed, with high expression levels observed in 79.1%, 69.8%, and 51.2% of cases, respectively, whereas p53 showed positive expression in only 34.9% of cases. Statistical analysis showed that expression of miRNA 34a was significantly associated with the expression of BRCA1 (p = 0.034). No significant associations were observed for KRAS, p53, or APC with the selected miRNAs. Moreover, the expression of miRNA 34a independently showed significant association with miRNA 30b (p = 0.000) and miRNA 137 (p = 0.001). None of the miRNA showed an association with the overall survival, patient demographics or the clinicopathological characteristics.ConclusionOur study highlights a potential bi-directional regulatory relationship between BRCA1 and miRNA 34a, suggesting that miRNA 34a may both respond to and influence BRCA1 activity within cellular signaling pathways. This complex interaction points to a layered regulatory network that could play a crucial role in tumor suppression in PDAC, underscoring the therapeutic potential of targeting this miRNA-protein crosstalk.

Protective effects of miR-24-2-5p in early stages of breast cancer bone metastasis

BackgroundBone is the most frequent site of metastasis for breast cancer (BC). Metastatic BC cells interact with bone cells, including osteoclasts and osteoblasts, creating a cancer niche where they seed and proliferate. MicroRNAs (miRNAs) are regulators of breast-to-bone metastasis progression. MiR-24-2-5p has previously been shown to have roles in both breast cancer progression and inhibition of osteogenic differentiation. However, a direct link between miR-24-2-5p activity and the onset of bone metastasis remains ill-defined.MethodsAnalysis of the expression of miR-24 forms (miR-24-2-5p, miR-24-3p, miR-24-1-5p) in the serum from early-stage BC patients at baseline (time of surgery) was conducted. MiR-24-2-5p overexpression in BC cells (NW1, a luc2-positive subpopulation of MDA-MB-231, and MCF7) was obtained by miRNA mimic transfection or lentivirus transduction. MiR-24-2-5p downregulation in BC cells (ZR-75-1, T-47D, SK-BR-3) was obtained by miRNA inhibitor transfection. Cell proliferation, migration and/or invasion assays were performed to assess BC cell functions after modulation of miR-24-2-5p expression. An animal model was used to assess the effect of miR-24-2-5p overexpression on early BC metastasis formation, as judged by bioluminescence imaging, and on bone remodelling, following measurement of circulating bone resorption (CTX-I) and bone formation (P1NP) markers. The effect of conditioned medium from miR-24-2-5p-overexpressing BC cells on human and murine osteoclast differentiation was investigated. Endogenous miR-24-2-5p expression levels were also quantified during murine osteoclast differentiation. RNA-sequencing (RNA-seq) analysis of BC cells was performed to evaluate transcriptomic changes associated with miR-24-2-5p overexpression. Selected modulated transcripts upon miR-24-2-5p overexpression were further validated by real-time qPCR.ResultsLow expression levels of miR-24-2-5p, but not other miR-24 forms (miR-24-3p, miR-24-1-5p), in the serum from early-stage BC patients were associated with a high risk to develop future (bone) metastases. MiR-24-2-5p was also present in small extracellular vesicles secreted from BC cells. Forced expression of miR-24-2-5p in BC cells (NW1, MCF7) reduced their malignant traits (migration, invasion, and proliferation) in vitro. Furthermore, miR-24-2-5p overexpression in NW1 cells reduced metastasis, particularly in bone, and decreased bone turnover in vivo. RNA-seq and real-time qPCR analyses of NW1 and MCF7 cells overexpressing miR-24-2-5p showed the downregulation of common transcripts (CNNM4, DCTD, FMR1, PIGS, HLA-A, ICK, SH3BGRL2, WDFY, TRAF9B, IL6ST, PEX10, TRIM59). The conditioned medium from BC cells overexpressing miR-24-2-5p decreased human and murine osteoclast differentiation in vitro. Additionally, endogenous miR-24-2-5p expression levels in murine bone marrow-derived monocytes decreased during their differentiation into osteoclasts, further suggesting an inhibitory role for miR-24-2-5p during osteoclastogenesis.ConclusionMiR-24-2-5p exerts multiple protective roles in the early steps of BC bone metastasis by reducing malignant BC cell traits and tumour cell dissemination in bone, as well as by reducing the differentiation of precursors into mature osteoclasts.

Energy restriction inhibits β-catenin ubiquitination to improve ischemic stroke injury via USP18/SKP2 axis.

Ischemic stroke (IS) remains a global health issue because of its great disability and mortality. Energy restriction (ER) has been justified to perform an inhibitory role in cerebral injury caused by IS. This research was purposed to inquire the potential molecular mechanism of ER in IS. To verify the function of ER in the animal and cell models of IS, rats were subjected to intermittent fasting (IF) and middle cerebral artery occlusion/reperfusion (MCAO/R) surgery and HAPI cells were treated with oxygen-glucose deprivation and reoxygenation (OGD/R) and 2-deoxyglucose (2-DG). It was disclosed that IF mitigated brain damage and inflammation in MCAO/R rats. Likewise, ER inhibited OGD/R-evoked microglial activation and inflammatory response. Of note, ubiquitin specific protease 18 (USP18) was uncovered to be the most significantly upregulated in MCAO/R rats receiving IF compared to free-feeding MCAO/R rats. Real-time quantitative polymerase chain reaction (RT-qPCR) and western blot verified that ER led to the promotion of USP18 expression. Moreover, downregulation of USP18 neutralized the meliorative effects of ER on OGD/R-treated HAPI cells. Functionally, USP18 restrained β-catenin ubiquitination to enhance its expression. In addition, our results manifested that S-phase kinase associated protein 2 (SKP2) contributed to degradation of β-catenin and USP18 abolished the role of SKP2 in β-catenin ubiquitination. Knockout of USP18 eliminated the protective effects of IF on MCAO/R rats, while SKP2 exacerbated brain damage and inflammation by decreasing β-catenin expression after IF. In summary, we validated that ER-induced USP18 exerts a suppressive function in IS damage through SKP2-mediated β-catenin ubiquitination.

SMURF1 and SMURF2 directly target GLI1 for ubiquitination and proteasome-dependent degradation

The transcription factor GLI1 is the main and final effector of the Hedgehog signaling pathway, which is involved in embryonic development, cell proliferation and stemness. Whether activated through canonical or non-canonical mechanisms, GLI1 aberrant activity is associated with Hedgehog-dependent cancers, including medulloblastoma, as well as other tumoral contexts. Notwithstanding a growing body of evidence, which have highlighted the potential role of post translational modifications of GLI1, the complex mechanisms modulating GLI1 stability and activity have not been fully elucidated. Here, we present a novel role played by SMURF1 and SMURF2 in the suppression of the Hedgehog/GLI signaling pathway through a direct targeting of GLI1. Indeed, the two SMURFs can interact with GLI1, exploiting the proline rich regions present on GLI1 protein, and trigger its polyubiquitination and proteasomal degradation, leading to a suppression of the Hedgehog pathway activity and a reduction of Hh-dependent tumor cell proliferation. Overall, this study adds new relevance to a tumor suppressive role of SMURFs on the Hedgehog pathway and confers upon them the status of potential therapeutic tools, either in canonical or non-canonical Hedgehog pathway aberrant activation.

A LysM Effector Mediates Adhesion and Plant Immunity Suppression in the Necrotrophic Fungus Botrytis cinerea.

LysM effectors are suppressors of chitin-triggered plant immunity in biotrophic and hemibiotrophic fungi. In necrotrophic fungi, LysM effectors might induce a mechanism to suppress host immunity during the short asymptomatic phase they establish before these fungi activate plant defenses and induce host cell death leading to necrosis. Here, we characterize a secreted LysM protein from a major necrotrophic fungus, Botrytis cinerea, called BcLysM1. Transcriptional induction of BcLysM1 gene was observed in multicellular appressoria, called infection cushions, in unicellular appressoria and in the early phase of infection on bean leaves. We confirmed that BcLysM1 protein binds chitin in the fungus cell wall and protects hyphae against degradation by external chitinases. This effector is also able to suppress the chitin-induced ROS burst in Arabidopsis thaliana, suggesting sequestration of chitooligosaccharides in apoplast during infection. Moreover, contribution of BcLysM1 in infection initiation and in adhesion to bean leaf surfaces were demonstrated. Our data show for the first time that a LysM effector can play a dual role in mycelial adhesion and suppression of chitin-triggered host immunity, both of which occur during the early asymptomatic phase of infection by necrotrophic fungi.

G-protein-coupled receptor 41 in cardiomyocytes: Effect of butyrate on intracellular Ca2+ and sarcomere shortening.

G-protein-coupled receptor 41 (GPR41) is a Gαi-coupled receptor activated by short-chain fatty acids (SCFAs). Here, we tested that GPR41 is also expressed in cardiomyocytes and exerts a direct negative inotropic effect when activated by SCFA butyrate. Primary cardiomyocytes were isolated from wild-type (WT) and GPR41 knockout (GPR41-/-) adult mice and intracellular Ca2+ concentration and cell shortening were measured using the IonOptix system. RNA localization (RNAScope), quantitative real-time polymerase chain reaction (qRT-PCR), immunofluorescence staining, and western blot were used to examine the expression of GPR41 in adult primary cardiomyocytes of WT and GPR41-/- mice. The effect of butyrate on shortening and intracellular Ca2+ transient via GPR41 was also tested in cardiomyocytes. We demonstrated for the first time the presence of GPR41s on cardiomyocytes. Butyrate dose-dependently decreased cell shortening and the amplitude of intracellular Ca2+ transients in cardiomyocytes from WT but not GPR41-/- mice. In WT cardiomyocytes, butyrate decreased caffeine-mediated amplitudes of intracellular Ca2+ transients from the sarcoplasmic reticulum (SR). Moreover, the inhibitory effects of butyrate on cell shortening and intracellular Ca2+ were pertussis toxin (PTX)-sensitive. Finally, butyrate decreased the activity of sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) and cellular 3'-5'-cyclic adenosine monophosphate (cAMP) content. In conclusion, GPR41 is expressed on cardiomyocytes. Butyrate, a known GPR41 agonist, reduces cardiomyocyte shortening and intracellular Ca2+ transient via decreasing Ca2+ content in the SR by inhibiting SERCA activity in a PTX-dependent manner. These findings establish that GPR41 is directly activated by SCFAs to decrease contraction and intracellular Ca2+ transient, highlighting the potential inhibitory role of GPR41 in cardiomyocytes.

The role of p16 gene and P16INK4a protein in hematologic malignancies and therapeutic implications: A systematic review.

Hematological malignancies encompass a diverse group of cancers affecting the blood, bone marrow and lymph nodes. The p16 gene, encoding the P16INK4A protein, plays a pivotal role in cell cycle regulation and tumor suppression. Understanding the involvement of p16 in the development and progression of hematological malignancies is crucial for advancing therapeutic strategies. This systematic review aims to elucidate the multifaceted roles of the p16 gene and P16INK4A protein in hematological malignancies, focusing on their impact on disease pathogenesis, prognostic significance and therapeutic implications. A comprehensive search was conducted across electronic databases, including PubMed, Scopus and Google Scholar, using predefined search terms related to p16, P16INK4A, hematological malignancies, and therapy. Studies published up to 2023 were included, encompassing clinical trials, observational studies, meta-analyses, and preclinical research. The review synthesizes evidence highlighting the dysregulation of the p16 pathway in various hematological cancers. Alterations in p16 expression levels, genetic mutations and epigenetic modifications contribute to disease initiation and progression. Moreover, the prognostic significance of p16 status in predicting therapeutic outcomes and patient survival is explored. The p16 gene and P16INK4A protein emerge as promising biomarkers and therapeutic targets in hematological malignancies. Integrating knowledge of p16 dysregulation into clinical practice holds the potential to optimize treatment strategies, enhance patient outcomes and pave the way for personalized medicine approaches in the management of these challenging diseases.

MiR-198 targets TOPORS: implications for oral squamous cell carcinoma pathogenesis.

miRNAs play a critical role in the progression of various diseases, including oral squamous cell carcinoma (OSCC), which represents a major health concern and is one of the leading causes for new cancer cases worldwide. The miRNA dysregulation causes havoc and could be attributed to various factors, with epigenetic silencing of tumor suppressor genes being a major contributor to tumorigenesis. In this study, we have explored the tumor suppressive role of miR-198 in OSCC. The tumor suppressive effect of miR-198 is established using miRNA analysis in OSCC cell lines, patient samples and xenograft nude mice model. The relationship between the miR-198 and TOPORS is explored using bioinformatics analyses, qRT-PCR, dual-luciferase reporter assay, Western blotting and cancer hall marks assays. The hypermethylation of the MIR198 promoter is confirmed using bisulfite sequencing PCR. We have found miR-198 to be upregulated in OSCC cells treated with 5-Azacytidine, a known DNA methyltransferase inhibitor. Upregulation of miR-198 in 5-Azacytidine treated OSCC cells appears to be due to methylation of the MIR198 promoter. Using bioinformatics analysis and dual-luciferase reporter assay, we have identified TOPORS (TOP1 binding arginine/serine rich protein, E3 ubiquitin ligase) as a novel gene target for miR-198. miR-198-mediated repression of TOPORS decreases cell proliferation and anchorage-independent growth and enhances apoptosis of OSCC cells, which is dependent on the presence of the 3'UTR in TOPORS. An inverse correlation between the expression levels of miR-198 and TOPORS is observed in OSCC patient samples, highlighting the biological relevance of their interaction. Delivery of a synthetic miR-198 mimic to OSCC cells results in a significant decrease in xenograft size in nude mice, potentiating its use in therapeutics. These results suggest that miR-198 is epigenetically silenced in OSCC, which promotes tumor growth, in part, by upregulating the levels of TOPORS.

TNF-α Suppression Attenuates Limbal Stem Cell Damage in Ocular Injury.

Ocular chemical injuries often cause uveal inflammation, upregulation of TNF-α at the limbus, and subsequent limbal stem cell (LSC) damage. In this study, we investigate the protective role of TNF-α suppression in LSC survival. Corneal alkali injuries were performed using NaOH as previously described by our group. Anterior chamber pH elevation in the absence of corneal alkali exposure was achieved by cannulation. A CX3CR1+/EGFP::CCR2+/RFP bone marrow chimera was used to study the role of innate immune cells in LSC damage, which was assessed by TUNEL assay, ABCB5, cytokeratin 12 and 13 staining, flow cytometry, in situ hybridization, and qPCR. Corneal neovascularization and conjunctivalization were evaluated by light microscopy. Intraperitoneal injection of 6.25 mg/kg infliximab was administered after irrigation. A TNFR1/2 knockout mouse was used to confirm the findings by a second method. Systemic administration of 6.25 mg/kg infliximab suppressed uveal inflammation after anterior chamber pH elevation or corneal alkali injury and led to reduction of TNF-α secreting CCR2+ and CX3CR1+ monocytes in the basal limbal tissue. In turn, this led to LSC survival (P < 0.01) and allowed reestablishment of K12+ epithelium (P < 0.05) on the injured cornea. Moreover, it led to less corneal neovascularization, conjunctivalization, and scarring, as compared with untreated animals. The protective effect of TNF-α suppression was confirmed in TNFR1/2 knockout mice. Prompt systemic administration of TNF-α inhibitor prevents LSC deficiency and facilitates corneal reepithelialization after alkali burn. TNF-α suppression may benefit the outcomes of other ocular injuries that cause LSC deficiency.

Study on the influence of digital inclusive finance on the development of provincial fishery economy and regional economic convergence in China

In recent years, the rapid development of digital inclusive finance in China has affected many aspects of social development, especially economic development, which has a good driving force. At the same time, the development of the fishery economy has been challenged by many aspects, and digital inclusive finance may inject new development momentum into the development of the fishery economy. Using the digital financial inclusion index and relevant data on the fishery economic development of 31 provinces, autonomous regions, and municipalities in China from 2013 to 2020, this paper empirically analyzes the impact of digital financial inclusion on provincial fishery economic development through the dual fixed effect panel data econometric model of controlled region and time. The main conclusions are as follows: The benchmark regression results show that digital inclusive finance can positively promote the development of the fishery economy at the significance level of 1%, and the digital development degree of digital inclusive finance also has a significant role in promoting the development of the fishery economy. After the endogeneity test of the system GMM model and a series of robustness tests, the model results are still significant. The results of the moderating effect model show that technological innovation plays a positive moderating role in the impact of digital inclusive finance on the development of the fishery economy, while the upgrading of the industrial structure plays an inhibitory role. Based on the results of the β convergence model, it can be found that there is no convergence in the level of fishery economic development among provinces. The development of digital inclusive finance will play a greater role in promoting areas with better fisheries and economic development, thus widening the development gap between regions. Finally, the paper discusses the effect of the conclusion and the improvement, which is of reference significance for the coordinated development of the fishery economy based on finance between regions.

Repressor MrERF4 and Activator MrERF34 Synergistically Regulate High Flavonol Accumulation Under UV-B Irradiation in Morella rubra Leaves.

Flavonols are important plant photoprotectants to defence UV-B irradiation, however, the underlying transcriptional regulatory mechanism of rapid flavonol accumulation in response to UV-B remains unknown. In this study, content of flavonols was significantly induced from 0.11 to 3.80 mg/g fresh weight by UV-B irradiation in leaves of Morella rubra seedlings. MrERF34 was identified as an activator that can regulate the expression of MrFLS2, and promoted flavonol biosynthesis with activator MrMYB12 under UV-B treatment. Transient overexpression of MrERF34 resulted in higher flavonol accumulation, while virus-induced gene silencing of MrERF34 reduced the content of flavonols in bayberry leaves. We further demonstrated that a repressor MrERF4 inhibited the expression of MrERF34 and MrMYB12 as well as MrFLS2 via ERF-associated-amphiphilic repression motif. Exposure to UV-B reduced the promoter activity and transcription of MrERF4, which weakened the inhibitory effect of MrERF4 on MrERF34, MrMYB12, and MrFLS2, leading to a tremendous accumulation of flavonols. Such inhibitory roles of MrERF4 in regulation of flavonol biosynthesis were further validated by transient overexpression in leaves of Nicotiana benthamiana and M. rubra. These findings enrich the synergistical regulatory mechanisms between repressor and activators in flavonol biosynthesis, and provide new insights into photoprotectants biosynthesis to mitigate UV-B stress in plants.

Mitochondrial apolipoprotein MIC26 is a metabolic rheostat regulating central cellular fuel pathways.

Mitochondria play central roles in metabolism and metabolic disorders such as type 2 diabetes. MIC26, a mitochondrial contact site and cristae organising system complex subunit, was linked to diabetes and modulation of lipid metabolism. Yet, the functional role of MIC26 in regulating metabolism under hyperglycemia is not understood. We used a multi-omics approach combined with functional assays using WT and MIC26 KO cells cultured in normoglycemia or hyperglycemia, mimicking altered nutrient availability. We show that MIC26 has an inhibitory role in glycolysis and cholesterol/lipid metabolism under normoglycemic conditions. Under hyperglycemia, this inhibitory role is reversed demonstrating that MIC26 is critical for metabolic adaptations. This is partially mediated by alterations of mitochondrial metabolite transporters. Furthermore, MIC26 deletion led to a major metabolic rewiring of glutamine use and oxidative phosphorylation. We propose that MIC26 acts as a metabolic "rheostat," that modulates mitochondrial metabolite exchange via regulating mitochondrial cristae, allowing cells to cope with nutrient overload.

Differential behavioral engagement of inhibitory interneuron subtypes in the zebra finch brain.

Inhibitory interneurons are highly heterogeneous circuit elements often characterized by cell biological properties, but how these factors relate to specific roles underlying complex behavior remains poorly understood. Using chronic silicon probe recordings, we demonstrate that distinct interneuron groups perform different inhibitory roles within HVC, a song production circuit in the zebra finch forebrain. To link these functional subtypes to molecular identity, we performed two-photon targeted electrophysiological recordings of HVC interneurons followed by post hoc immunohistochemistry of subtype-specific markers. We find that parvalbumin-expressing interneurons are highly modulated by sensory input and likely mediate auditory gating, whereas a more heterogeneous set of somatostatin-expressing interneurons can strongly regulate activity based on arousal. Using this strategy, we uncover important cell-type-specific network functions in the context of an ethologically relevant motor skill.

From nuclear to extracellular PTEN: Multiple roles in tumor suppression and immune modulation

In this issue of Developmental Cell, Zhang etal. report that secreted PTEN reprograms immunosuppressive tumor-associated macrophages into an inflammatory phenotype by binding to PLXDC2, which enhances antitumor immunity. This Preview discusses diverse functions of PTEN in the nucleus, cytoplasm, and extracellular matrix, highlighting its multifaceted roles in cancer.

Water phase transition and signal nulling in 3D dual-echo adiabatic inversion-recovery UTE (IR-UTE) imaging of myelin.

The semisolid myelin sheath has very fast transverse relaxation and is invisible to conventional MRI sequences. UTE sequences can detect signal from myelin. The major challenge is the concurrent detection of various water components. The inversion recovery (IR)-based UTE (IR-UTE) sequence employs an adiabatic inversion pulse to invert and suppress water magnetizations. TI plays a key role in water suppression, with negative water magnetizations (negative phase) before the null point and positive water magnetizations (positive phase) after the null point. A series of dual-echo IR-UTE images were acquired with different TIs to detect water phase transition. The effects of TR in phase transition and water suppression were also investigated using a relatively long TR of 500 ms and a short TR of 106 ms. The water phase transition in dual-echo IR-UTE imaging of myelin was investigated in five ex vivo and five in vivo human brains. An apparent phase transition was observed in the second echo at the water signal null point, where the myelin signal was selectively detected by the UTE data acquisition at the optimal TI. The water phase transition point varied significantly across the brain when the long TR of 500 ms was used, whereas the convergence of TIs was observed when the short TR of 106 ms was used. The results suggest that the IR-UTE sequence with a short TR allows uniform inversion and nulling of water magnetizations, thereby providing volumetric imaging of myelin.

ATF3 suppresses 3T3-L1 adipocyte adipogenesis via transcriptional repressing USP53.

Obesity is a widespread nutritional disorder, leading to a strong predisposition towards adverse health consequences. Activating transcription factor 3 (ATF3), a stress-induced transcription factor, has been documented as a therapeutic target for obesity. The intent of this project was to characterize the detailed role of ATF3 in adipogenesis during the process of obesity and its obscure downstream mechanism. After adipogenic differentiation, RT-qPCR and Western Blot examined ATF3 and ubiquitin-specific peptidase 53 (USP53) mRNA levels and protein levels. Adipogenesis was identified by Oil-red O staining, triglyceride (TG) and Western Blot. JASPAR database, ChIP and luciferase reporter assays predicated and validated the transcriptional regulation of USP53 by ATF3. Western Blot also examined the protein levels of ras homolog family member A (RhoA)/Rho-associated coiled-coil kinase (ROCK) pathway-involved proteins. ATF3 mRNA level and protein level were depleted in the differentiated 3T3-L1 adipocytes and ATF3 elevation hindered the adipogenesis of 3T3-L1 adipocytes. ATF3 suppressed the transcription of USP53 as a transcription factor and lowered USP53 expression. Eventually, USP53 upregulation partially blunted the inhibitory role of ATF3 overexpression in adipogenesis and RhoA/ROCK pathway. Consequently, ATF3 might transcriptionally inactivate USP53 to repress adipocyte adipogenesis and downregulate RhoA/ROCK pathway.

Inhibitory Role of L-theanine, a Structural Analogue of Glutamate, Against GluR5 Kainate Receptor and its Prospective Utility Against Excitotoxicity.

Overactivation of receptors that respond to excitatory neurotransmitters can result in various harmful outcomes, such as the inability to properly modulate calcium levels, generation of free radicals, initiation of the mitochondrial permeability transition, and subsequent secondary damage caused by excitotoxicity. A non-proteinogenic amino acid of tea, L-theanine, is structurally related to glutamate, the major stimulatory neurotransmitter in the brain. Previous reports have emphasised its ability to bind with glutamate receptors. An in-depth understanding of the binding compatibility between ionotropic glutamate receptors and L-theanine is a compelling necessity. In this molecular docking study, the antagonistic effect of L-theanine and its possible therapeutic benefit in GluR5 kainate receptor inhibition has been evaluated and compared to the familiar AMPA and kainite receptor antagonists, cyanoquinoxaline (CNQX) and dinitroquinoxaline (DNQX), using Molegro Virtual Docker 7.0.0. The capacity of L-theanine to cohere with the GluR5 receptor was revealed to be higher than that of glutamate, although it could not surpass the high binding tendency of competitive antagonists CNQX and DNQX. Nonetheless, the drug-likeness score and the blood-brain barrier traversing potential of L-theanine were higher than CNQX and DNQX. The study provides an inference to the advantage of L-theanine, which can be a safe and effective alternative natural therapy for rescuing neuronal death due to excitotoxicity.

Kunitz-type trypsin inhibitor from durian (Durio zibethinus) employs a distinct loop for trypsin inhibition.

Kunitz-type trypsin inhibitors are ubiquitous in plants. They have been proposed to be a part of a defense mechanism against herbivores. Trypsin inhibitors also have potential applications in the biotechnology industry, such as in mammalian cell culture. We discovered that durian (Durio zibethinus) seed contains Kunitz-type trypsin inhibitors as identified by N-terminal sequencing and mass spectrometry. Eleven new trypsin inhibitors were cloned. The D. zibethinus trypsin inhibitors (DzTIs) that are likely expressed in the seed were produced as recombinant proteins and tested for trypsin inhibitory activity. Their inhibitory activity and crystal structures are similar to the soybean trypsin inhibitor. Surprisingly, a crystal structure of the complex between DzTI-4, the DzTI with the lowest inhibitory constant, and bovine trypsin revealed that DzTI-4 utilized a novel tryptophan-containing β1-β2 loop to bind trypsin. Site-direct mutagenesis confirmed the inhibitory role of this loop. DzTI-4 was not toxic to the HEK293 cells and could be used in place of the soybean trypsin inhibitor for culturing the cells under serum-free conditions. DzTI-4 was not toxic to mealworms. However, a mixture of DzTIs extracted from durian seed prevented weight gain in mealworms, suggesting that multiple trypsin inhibitors are required to achieve the antinutritional effect. This study highlights the biochemical diversity of the inhibitory mechanism of Kunitz-type trypsin inhibitors and provides clues for further application of these inhibitors.

Genetic variation at 11q23.1 confers colorectal cancer risk by dysregulation of colonic tuft cell transcriptional activator POU2AF2

BackgroundCommon genetic variation at 11q23.1 is associated with colorectal cancer (CRC) risk, exerting local expression quantitative trait locus (cis-eQTL) effects on POU2AF2, COLCA1 and POU2AF3 genes. However, complex linkage disequilibrium...

Transcription factor-dependent regulatory networks of sexual reproduction in Fusarium graminearum.

Transcription factors (TFs) involved in sexual reproduction in filamentous fungi have been characterized. However, we have little understanding of how these TFs synergize within regulatory networks resulting in sexual development. We investigated 13 TFs in Fusarium graminearum, whose knockouts exhibited abortive or arrested phenotypes during sexual development to elucidate the transcriptional regulatory cascade underlying the development of the sexual fruiting bodies. A Bayesian network of the TFs was inferred based on transcriptomic data from key stages of sexual development. We evaluated in silico knockout impacts to the networks of the developmental phenotypes among the TFs and guided knockout transcriptomics experiments to properly assess regulatory roles of genes with same developmental phenotypes. Additional transcriptome data were collected for the TF knockouts guided by the stage at which their phenotypes appeared and by the cognate in silico prediction. Global TF networks revealed that TFs within the mating-type locus (MAT genes) trigger a transcriptional cascade involving TFs that affected early stages of sexual development. Notably, PNA1, whose knockout mutants produced exceptionally small protoperithecia, was shown to be an upstream activator for MAT genes and several TFs essential for ascospore production. In addition, knockout mutants of SUB1 produced excessive numbers of protoperithecia, wherein MAT genes and pheromone-related genes exhibited dysregulated expression. We conclude that PNA1 and SUB1 play central and suppressive roles in initiating sexual reproduction, respectively. This comprehensive investigation contributes to our understanding of the transcriptional framework governing the multicellular body plan during sexual reproduction in F. graminearum.IMPORTANCEUnderstanding transcriptional regulation of sexual development is crucial to the elucidation of the complex reproductive biology in Fusarium graminearum. We performed gene knockouts on 13 transcription factors (TFs), demonstrating knockout phenotypes affecting distinct stages of sexual development. Using transcriptomic data across stages of sexual development, we inferred a Bayesian network of these TFs that guided experiments to assess the robustness of gene interactions using a systems biology approach. We discovered that the mating-type locus (MAT genes) initiates a transcriptional cascade, with PNA1 identified as an upstream activator essential for early sexual development and ascospore production. Conversely, SUB1 was found to play a suppressive role, with knockout mutants exhibiting excessive protoperithecia due to abnormally high expression of MAT and pheromone-related genes. These findings highlight the central roles of PNA1 and SUB1 in regulating other gene activity related to sexual reproduction, contributing to a deeper understanding of the mechanisms of the multiple TFs that regulate sexual development.