Molecular Biology Research Communications最新文献

Heterocephalus glaber, known as the Naked mole-rat, has an extraordinary immunity to Alzheimer's disease. The pathological hallmark of Alzheimer's disease is cerebral accumulations of plaques, consisting of self-aggregated amyloid beta peptides. Homo sapiens and H. glaber amyloid beta peptides are different in only one amino acid. Herein, computational structural analyses were carried out to determine whether plaque development in H. glaber is prevented by the replacement of His13 with Arg13 in the amyloid beta peptide. AlphaFold2 was used to predict the structure of the H. glaber amyloid beta peptide. HADDOCK and Hex were used to self-dock the peptides and dock ions on peptides, respectively. Illustrations were made by PyMol and ChimeraX. Using VMD, we calculated the radius of gyration. The phylogenetic analysis was conducted by Mega. The results showed an accurate structure with two alpha helices separated by a short coil for H. glaber. Self-docking of the two amyloid beta peptides demonstrated a globular conformation in the H. glaber dimer, implying the unlikeliness of amyloid beta peptides' self-aggregation to form fibrillar structures. This conformational state resulted in lower electrostatic energy compared to H. sapiens, contributing to H. glaber's lower tendency for fibril and, ultimately, plaque formation. Phylogenetic analysis confirmed that amyloid precursor protein is highly conserved in each taxon of rodentia and primata. This study provides insight into the connection between the structure of H. glaber amyloid beta and its plaque formation properties, showing that the Arg13 in H. glaber leads to fibril instability, and might prevent senile plaque accumulation.

Sphingosine 1 phosphate (S1P) is involved in the pathogenesis of asthma by stimulation of the alpha-smooth muscle actin (SMA) expression and remodeling of fibroblasts. This study was designed to determine the effects of selected micro RNAs in regulation of S1P and related metabolic pathways in a human lung fibroblast cell line. The fibroblast cell line (CIRC-HLF, C580) was cultured and transfected with individual viral vectors carrying miR124, mi125b, mi133b or mi130a. After 48 hours, expression level of miRNAs and their target genes, sphingosine kinase 1(SPHK1), sphingosine 1-phosphate lyase 1 (SGPL1), sphingosine 1- phosphate receptor 1 (S1PR1) and sphingosine 1- phosphate receptor 2 (S1PR2) were determined. Expression of miRNA and mRNA determined by reverse transcriptionquantitative polymerase chain reaction (qPCR) showed that the expression level of the miRNAs was significantly higher in human lung fibroblasts following transfection compared to controls (vector backbone without miRNA). The expressions of miRNAs-targeted genes were significantly downregulated in transfected fibroblasts compared to control cells (p<0.05). Data show that miR 124, miR 125b, miR 133b and miR130a by targeting regulatory genes in S1P-pathway can down-regulate key factors such as SPHK1, SGPL1, S1PR1 and S1PR2 genes in lung fibroblasts. The results showed that S1P pathway and key factors are suppressed in lung fibroblasts expressing miR124, miR125b, miR130a or miR133b. It appears that suppression of any of the intermediate factors in S1P by miRNA can affect the regulation of the entire S1P pathway.

Cholesterol and the Wnt/β-catenin pathway have an effective role in the proliferation, survival, drug resistance, immune exhaustion, and metastasis of all types of cancer cells. Considering the role of LDLR and LRP6 proteins in cholesterol uptake by cells and activation of Wnt/β-catenin pathway, this study aims to examine the gene expression of LDLR and LRP6 in cell lines of breast cancer. Human breast cancer cell lines MCF7, MD468 and SKBR3 were cultured in suitable conditions and after extracting total RNA from them, real-Time PCR was used to measure the levels of gene expression for LDLR and LRP6. Our results showed that the expression of LDLR and LRP6 genes is significantly increased in MCF7 and MD468 cells compared to SKBR3 cells. These results suggest that LRP6 and LDLR can be considered as a therapeutic target in tumors that have a genetic profile similar to MCF7 and MD468 cells.

Biliary atresia (BA) is the primary cause of neonatal jaundice with various pathological mechanisms. Many BA patients may experience progressive liver dysfunction and eventually need a liver transplant. Therefore, identifying potential non-invasive biomarkers for BA is crucial. miR-122, the most abundant microRNA in the liver, plays significant roles in different liver diseases. This study aimed to assess miR-122 levels in BA patients. Eighteen patients with biliary atresia were selected at random from the Shiraz Pediatric Liver Cirrhosis Cohort Study (SPLCCS), along with 18 healthy controls. Blood samples were collected, and biochemical parameters (such as liver function tests) were measured. Quantitative reverse-transcription PCR (RT-PCR) was conducted on serum samples from both the case and control groups to analyze miR-122 levels. The study results indicated that serum miR-122 expression in BA patients was elevated compared to the control group, although it did not reach statistical significance. Additionally, no correlation was found between miR-122 expression and serum levels of liver enzymes or other laboratory findings in BA cases. miR-122 could be a potential target for diagnosing BA; however, further research with a larger population is necessary to determine if miR-122 could serve as a useful biomarker for diagnosing BA.

L-asparaginase is a commercial enzyme with a wide variety of applications. Asparaginase is known as an anti-cancer agent that is effective for the treatment of certain lymphomas and leukemias by growth inhibition of human cancer cells. Additionally, asparaginase is used in the food industry in a pretreatment process to decrease the accumulation of carcinogenic acrylamide. In this paper, different aspects of bacterial and fungal asparaginases such as mass, hydrophobicity and hydrophilicity of pseudo amino acid composition (PseAAC), physicochem-ical properties, and structural motifs were studied, and ROC curve statistical analysis was used for the comparison. The results showed that none of the physicochemical properties of fungal and bacterial asparaginase could not be differed, except molecular weight and sequence length. MEME Suite analysis demonstrated that there was a motif that was specific for bacterial asparaginases. However, analysis based on the concept of PseACC indicated a differentiation line between fungal and bacterial asparaginases. In conclusion, although there was not any specific demonstration to separate the bacterial and fungal asparaginases in the case of physicochemical properties, PseAAC analysis can be an appropriate and usable method to differentiate between them.

Herein, a detailed molecular phylogeny analysis was developed to determine the phylogenetic position of a new freshwater histozoic myxosporean cnidarian, Henneguya markiana sp. nov. from the world's largest tropical wetland area, Pantanal, Brazil. The new species is described using an integrative taxonomy approach including morphology, biological traits and molecular data. Phylogenetic analysis inferred by Maximum Likehood method showed the new Henneguya species in a well-supported clade of myxosporean gill parasites of South American characids fishes. In this same clade, the new Henneguya described appeared in a sub-clade clustering with H. lacustris and H. chydadea. Nevertheless, the sequences of the new species and H. lacustris and H. chydadea have a large genetic divergence of 10.4% (148 nucleotides-nt) and 10.5% (147 nt) respectively. To the best of our knowledge, this is the first report of a cnidarian myxosporean species parasitizing a fish from Stevardiinae from South America. In the light of the differences observed from the integrative taxonomy, we are confident that this isolate is a new species of Henneguya, increasing the knowledge of diversity of this enigmatic group of cnidarians.

tRNAs act as adaptors during protein synthesis and are chemically modified post-transcriptionally for their structural stability as well as accuracy of the translation. Hypomodifications of tRNAs are known to cause various human diseases, including cancer. Studies in bacteria and yeasts showed that levels of tRNA modifications vary under different stress conditions, enabling the organism to modulate gene expression for survival. Isopentelylation of the base 37 (i⁶A37) in the anticodon stem-loop by tRNA isopentenyltransferase (MiaA) is well-conserved modification present in prokaryotes and eukaryotes. i⁶A37 modification increases both the speed and fidelity of translation. A homozygous p.Arg323Gln mutation in the tRNA binding region of tRNA isopentenyltransferase reduced i⁶A37 levels in humans, affecting mitochondrial translation and thereby causing neurodevelopmental disorder. In this study, we mutated the Arg residue at the conserved position to Gln in Mycobacterium tuberculosis (M. tb) MiaA and analyzed the i6A modification activity of the enzyme on its target tRNAs. We found that p.Arg274Gln mutant MiaA could not modify the target tRNAs, tRNA^LeuCAA, tRNA^PheGAA, and tRNA^SerCGA from M. tb, confirming the role of Arg residue in tRNA binding.

Autophagy is a cellular process that plays a major role in the fate of tumor cells. Understanding the role of autophagy in cancer therapy is a major challenge, particularly for breast cancer as the sole top cause of mortality among women. In this study, we evaluated the gene expression of mTOR and Beclin1 and the levels of p62 protein, in breast tumors and compared them to a control condition. To explore the role of autophagy in breast cancer, we acquired tumor biopsies from 41 new cases of breast cancer patients. We extracted total RNA from each biopsy and used real-time PCR to quantify Beclin1 and mTOR-specific RNA expression. In addition, we evaluated the expression of the p62 protein in paraffin-embedded tumor tissue using the immunohistochemistry technique. The data revealed an upregulation of Beclin1 and a downregulation of mTOR in tumor tissues compared to the control condition. The correlation between p62 expression and Beclin1/mTOR showed a negative and positive correlation, respectively, confirming autophagy activation in the tumor tissues. However, there was no correlation between autophagy markers and tumor size, grade and stage. The findings revealed that autophagy activation was found in breast tumor tissues, suggesting that autophagy can be a target for breast cancer therapy.

Maple syrup urine disease (MSUD) represents an infrequent metabolic disease precipitated by an insufficiency of the enzymatic complex known as branched-chain alpha-keto acid dehydrogenase. MSUD can be classified as classic (severe), intermediate, or intermittent based on the severity of the condition. The disease is associated with mutations in several genes, including BCKDHA, BCKDHB, DBT, and DLD. This study aimed to investigate the genetic landscape of MSUD in Iranian patients and explore the clinical implications of identified gene variants. A comprehensive analysis was conducted using various molecular techniques and bioinformatics tools to predict protein stability, pathogenicity, amino acid conservation, and secondary/tertiary structure. The in silico analysis highlighted high-risk pathogenic variants and provided insights into their potential impact on protein structure and function. Furthermore, the predicted 3D structures of wild-type and mutant proteins elucidated structural differences. Protein-protein interaction analysis shed light on the network of interactions involving MSUD-related proteins. The Iranome database uncovered a potential pathogenic variant (c.554C>T) in the Persian population. This research contributes to a better understanding of MSUD genetics in the Iranian population and outlines potential avenues for further clinical investigations. The findings have implications for genetic testing, prognosis, and genetic counseling in affected families.