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International Journal of Molecular... Jun 2024The most significant genetic influence on eye color pigmentation is attributed to the intronic SNP rs12913832 in the gene, which interacts with the promoter region of...
The most significant genetic influence on eye color pigmentation is attributed to the intronic SNP rs12913832 in the gene, which interacts with the promoter region of the contiguous gene. This interaction, through the formation of a chromatin loop, modulates the transcriptional activity of , directly affecting eye color pigmentation. Recent advancements in technology have elucidated the precise spatial organization of the genome within the cell nucleus, with chromatin architecture playing a pivotal role in regulating various genome functions. In this study, we investigated the organization of the chromatin close to the locus in human lymphocyte nuclei using fluorescence in situ hybridization (FISH) and high-throughput chromosome conformation capture (Hi-C) data. The 3 Mb of genomic DNA that belonged to the chromosomal region 15q12-q13.1 revealed the presence of three contiguous chromatin loops, which exhibited a different level of compaction depending on the presence of the A or G allele in the SNP rs12913832. Moreover, the analysis of the genomic organization of the genes has demonstrated that this chromosomal region is evolutionarily highly conserved, as evidenced by the analysis of syntenic regions in species from other Vertebrate classes. Thus, the role of rs12913832 variant is relevant not only in determining the transcriptional activation of the gene but also in the chromatin compaction of a larger region, underscoring the critical role of chromatin organization in the proper regulation of the involved genes. It is crucial to consider the broader implications of this finding, especially regarding the potential regulatory role of similar polymorphisms located within intronic regions, which do not influence the same gene by modulating the splicing process, but they regulate the expression of adjacent genes. Therefore, caution should be exercised when utilizing whole-exome sequencing for diagnostic purposes, as intron sequences may provide valuable gene regulation information on the region where they reside. Thus, future research efforts should also be directed towards gaining a deeper understanding of the precise mechanisms underlying the role and mode of action of intronic SNPs in chromatin loop organization and transcriptional regulation.
Topics: Polymorphism, Single Nucleotide; Humans; Chromatin; Guanine Nucleotide Exchange Factors; Animals; Evolution, Molecular; Membrane Transport Proteins; In Situ Hybridization, Fluorescence; Vertebrates; Pigmentation; Ubiquitin-Protein Ligases
PubMed: 38928306
DOI: 10.3390/ijms25126602 -
International Journal of Molecular... Jun 2024The present study examined how P2X7 receptor knockout (KO) modulates central post-stroke pain (CPSP) induced by lesions of the ventrobasal complex (VBC) of the thalamus...
The present study examined how P2X7 receptor knockout (KO) modulates central post-stroke pain (CPSP) induced by lesions of the ventrobasal complex (VBC) of the thalamus in behaviors, molecular levels, and electrical recording tests. Following the experimental procedure, the wild-type and P2X7 receptor KO mice were injected with 10 mU/0.2 μL type IV collagenase in the VBC of the thalamus to induce an animal model of stroke-like thalamic hemorrhage. Behavioral data showed that the CPSP group induced thermal and mechanical pain. The P2X7 receptor KO group showed reduced thermal and mechanical pain responses compared to the CPSP group. Molecular assessments revealed that the CPSP group had lower expression of NeuN and KCC2 and higher expression of GFAP, IBA1, and BDNF. The P2X7 KO group showed lower expression of GFAP, IBA1, and BDNF but nonsignificant differences in KCC2 expression than the CPSP group. The expression of NKCC1, GABAa receptor, and TrkB did not differ significantly between the control, CPSP, and P2X7 receptor KO groups. Muscimol, a GABAa agonist, application increased multiunit numbers for monitoring many neurons and [Cl] outflux in the cytosol in the CPSP group, while P2X7 receptor KO reduced multiunit activity and increased [Cl] influx compared to the CPSP group. P2X4 receptor expression was significantly decreased in the 100 kDa but not the 50 kDa site in the P2X7 receptor KO group. Altogether, the P2X7 hypothesis of CPSP was proposed, wherein P2X7 receptor KO altered the CPSP pain responses, numbers of astrocytes and microglia, CSD amplitude of the anterior cingulate cortex and the medial dorsal thalamus, BDNF expression, [Cl] influx, and P2X4 expression in 100 kDa with P2X7 receptors. The present findings have implications for the clinical treatment of CPSP symptoms.
Topics: Animals; Receptors, Purinergic P2X7; Mice; Mice, Knockout; Stroke; K Cl- Cotransporters; Male; Pain; Disease Models, Animal; Brain-Derived Neurotrophic Factor; Symporters; Mice, Inbred C57BL; Neurons; Muscimol; Glial Fibrillary Acidic Protein; Thalamus
PubMed: 38928280
DOI: 10.3390/ijms25126577 -
International Journal of Molecular... Jun 2024The FUT2 gene encodes an enzyme called α-1,2-fucosyltransferase, which is involved in the formation of blood group antigens AB0(H) and is also involved in the processes...
The FUT2 gene encodes an enzyme called α-1,2-fucosyltransferase, which is involved in the formation of blood group antigens AB0(H) and is also involved in the processes of vitamin B12 absorption and its transport between cells. FUT2 gene polymorphisms are associated with vitamin B12 levels in the body. Vitamin B12 deficiency associated with hyperhomocysteinemia is a major risk factor for cardiovascular diseases (CVDs), which are one of the main causes of death in patients after kidney transplantation. The aim of our study was to determine the impact of the rs602662 (G>A) polymorphism of the FUT2 gene on the functionality of transplanted kidneys and the risk of CVD in patients after kidney transplantation. The study included 402 patients treated with immunosuppression (183 patients taking cyclosporine (CsA) and 219 patients taking tacrolimus (TAC)). The analysis of the FUT2 rs602662 (G>A) polymorphism was performed using real-time PCR. Patients with CsA were more likely to be underweight (1.64% vs. 0.91%) and obese (27.87% vs. 15.98%), while those taking TAC were more likely to be of normal weight (39.27%) or overweight (43.84%). No statistically significant differences were observed comparing the mean blood pressure, both systolic and diastolic. The renal profile showed a higher median urea nitrogen concentration in patients with CsA (26.45 mg/dL (20.60-35.40) vs. 22.95 mg/dL (17.60-33.30), = 0.004). The observed frequency of rs602662 alleles of the FUT2 gene was similar in the analyzed groups. The A allele was present in 43.7% of patients with CsA and 41.1% of those taking TAC (OR = 0.898; 95% CI: 0.678-1.189; = 0.453). In the group with CsA, the GG genotype was present in 32.2% of patients, the GA in 48.1% and the AA in 19.7%. A similar distribution was obtained in the TAC group: GG-33.8%, GA-50.2%, and AA-16.0%. An association of genotypes containing the G allele with a higher incidence of hypertension was observed. The G allele was present in 65% of people with hypertension and in 56% of patients with normal blood pressure ( = 0.036). Moreover, the evaluation of the renal parameters showed no effect of the FUT2 polymorphism on the risk of organ rejection because the levels of creatinine, eGFR, potassium, and urea nitrogen were prognostic of successful transplantation. Our results suggest that the rs6022662 FUT2 polymorphism may influence the risk of cardiovascular diseases.
Topics: Humans; Fucosyltransferases; Galactoside 2-alpha-L-fucosyltransferase; Kidney Transplantation; Male; Female; Cardiovascular Diseases; Middle Aged; Polymorphism, Single Nucleotide; Adult; Risk Factors; Genetic Predisposition to Disease; Genotype; Immunosuppressive Agents; Cyclosporine; Tacrolimus
PubMed: 38928269
DOI: 10.3390/ijms25126562 -
International Journal of Molecular... Jun 2024LPA receptors were expressed in TREx HEK 293 cells, and their signaling and phosphorylation were studied. The agonist, lysophosphatidic acid (LPA), increased...
LPA receptors were expressed in TREx HEK 293 cells, and their signaling and phosphorylation were studied. The agonist, lysophosphatidic acid (LPA), increased intracellular calcium and ERK phosphorylation through pertussis toxin-insensitive processes. Phorbol myristate acetate, but not LPA, desensitizes LPA-mediated calcium signaling, the agonists, and the phorbol ester-induced LPA internalization. Pitstop 2 (clathrin heavy chain inhibitor) markedly reduced LPA-induced receptor internalization; in contrast, phorbol ester-induced internalization was only delayed. LPA induced rapid β-arrestin-LPA receptor association. The agonist and the phorbol ester-induced marked LPA receptor phosphorylation, and phosphorylation sites were detected using mass spectrometry. Phosphorylated residues were detected in the intracellular loop 3 (S221, T224, S225, and S229) and in the carboxyl terminus (S321, S325, S331, T333, S335, Y337, and S343). Interestingly, phosphorylation sites are within sequences predicted to constitute β-arrestin binding sites. These data provide insight into LPA receptor signaling and regulation.
Topics: Humans; Receptors, Lysophosphatidic Acid; Phosphorylation; HEK293 Cells; Signal Transduction; Lysophospholipids; beta-Arrestins; Binding Sites; Calcium Signaling
PubMed: 38928196
DOI: 10.3390/ijms25126491 -
International Journal of Molecular... Jun 2024The gene encodes for the CFTR ion channel, which is responsible for the transport of chloride and bicarbonate across the plasma membrane. Mutations in the gene result...
The gene encodes for the CFTR ion channel, which is responsible for the transport of chloride and bicarbonate across the plasma membrane. Mutations in the gene result in impaired ion transport, subsequently leading to perturbed secretion in all exocrine glands and, therefore, the multi-organ disease cystic fibrosis (CF). In recent years, several studies have reported on CFTR expression in immune cells as demonstrated by immunofluorescence, flow cytometry, and immunoblotting. However, these data are mainly restricted to single-cell populations and show significant variation depending on the methodology used. Here, we investigated transcription and protein expression using standardized protocols in a comprehensive panel of immune cells. Methods: We applied a high-resolution Western blot protocol using a combination of highly specific monoclonal CFTR antibodies that have been optimized for the detection of CFTR in epithelial cells and healthy primary immune cell subpopulations sorted by flow cytometry and used immortalized cell lines as controls. The specificity of CFTR protein detection was controlled by peptide competition and enzymatic Peptide-N-Glycosidase-F (PNGase) digest. transcripts were analyzed using quantitative real-time PCR and normalized to the level of epithelial T84 cells as a reference. Results: mRNA expression could be shown for primary CD4 T cells, NK cells, as well as differentiated THP-1 and Jurkat T cells. In contrast, we failed to detect transcripts for CD14 monocytes and undifferentiated THP-1 cells, as well as for B cells and CD8 T cells. Prominent immunoreactive bands were detectable by immunoblotting with the combination of four CFTR antibodies targeting different epitopes of the CFTR protein. However, in biosamples of non-epithelial origin, these CFTR-like protein bands could be unmasked as false positives through peptide competition or PNGase digest, meaning that the observed mRNA transcripts were not necessarily translated into CFTR proteins, which could be detected via immunoblotting. Our results confirm that mRNA expression in immune cells is many times lower than in that cells of epithelial origin. The immunoreactive signals in immune cells turned out to be false positives, and may be provoked by the presence of a high-affinity protein with a similar epitope. Non-specific binding (e.g., Fab-interaction with glycosyl branches) might also contribute to false positive signals. Our findings highlight the necessity of accurate controls, such as CFTR-negative cells, as well as peptide competition and glycolytic digest in order to identify genuine CFTR protein by immunoblotting. Our data suggest, furthermore, that CFTR protein expression data from techniques such as histology, for which the absence of a molecular weight or other independent control prevents the unmasking of false positive immunoreactive signals, must be interpreted carefully as well.
Topics: Cystic Fibrosis Transmembrane Conductance Regulator; Humans; RNA, Messenger; Leukocytes, Mononuclear; Blotting, Western; Real-Time Polymerase Chain Reaction; Cystic Fibrosis; Killer Cells, Natural; Flow Cytometry; CD4-Positive T-Lymphocytes
PubMed: 38928073
DOI: 10.3390/ijms25126367 -
Biomolecules Jun 2024Abdominal aortic aneurysm (AAA) is a chronic aortic disease that lacks effective pharmacological therapies. This study was performed to determine the influence of...
Abdominal aortic aneurysm (AAA) is a chronic aortic disease that lacks effective pharmacological therapies. This study was performed to determine the influence of treatment with the gasdermin D inhibitor necrosulfonamide on experimental AAAs. AAAs were induced in male apolipoprotein E-deficient mice by subcutaneous angiotensin II infusion (1000 ng/kg body weight/min), with daily administration of necrosulfonamide (5 mg/kg body weight) or vehicle starting 3 days prior to angiotensin II infusion for 30 days. Necrosulfonamide treatment remarkably suppressed AAA enlargement, as indicated by reduced suprarenal maximal external diameter and surface area, and lowered the incidence and reduced the severity of experimental AAAs. Histologically, necrosulfonamide treatment attenuated medial elastin breaks, smooth muscle cell depletion, and aortic wall collagen deposition. Macrophages, CD4 T cells, CD8 T cells, and neovessels were reduced in the aneurysmal aortas of necrosulfonamide- as compared to vehicle-treated angiotensin II-infused mice. Atherosclerosis and intimal macrophages were also substantially reduced in suprarenal aortas from angiotensin II-infused mice following necrosulfonamide treatment. Additionally, the levels of serum interleukin-1β and interleukin-18 were significantly lower in necrosulfonamide- than in vehicle-treated mice without affecting body weight gain, lipid levels, or blood pressure. Our findings indicate that necrosulfonamide reduced experimental AAAs by preserving aortic structural integrity as well as reducing mural leukocyte accumulation, neovessel formation, and systemic levels of interleukin-1β and interleukin-18. Thus, pharmacologically inhibiting gasdermin D activity may lead to the establishment of nonsurgical therapies for clinical AAA disease.
Topics: Animals; Angiotensin II; Aortic Aneurysm, Abdominal; Mice; Male; Sulfonamides; Apolipoproteins E; Phosphate-Binding Proteins; Disease Models, Animal; Mice, Inbred C57BL; Macrophages; Indoles; Mice, Knockout, ApoE; Gasdermins
PubMed: 38927129
DOI: 10.3390/biom14060726 -
Zhongguo Shi Yan Xue Ye Xue Za Zhi Jun 2024To screen interleukin (IL)-1β secretion-related membrane transporters by macrophage experiment and conventional knockout mice.
OBJECTIVE
To screen interleukin (IL)-1β secretion-related membrane transporters by macrophage experiment and conventional knockout mice.
METHODS
THP-1 cell line was differentiated to obtain human THP-1-derived macrophages, and the primary macrophages were obtained from human peripheral blood. wild-type mice with the same sex and age were used as the controls of knockout mice. The macrophages in abdominal cavity and bone marrow of mice were cultivated. The cells were treated with ABCC1/MRP1, ABCG2/BCRP, ABCB1/P-gp, OATP1B1, and MATE transporter inhibitors, then stimulated by lipopolysaccharide and adenosine triphosphate. The secretion level of IL-1β was detected by ELISA, Western blot, and immunofluorescence.
RESULTS
After inhibiting ABCC1/MRP1 transporter, the secretion of IL-1β decreased significantly, while inhibition of the other 4 transporters had no effect. In animal experiment, the level of IL-1β secreted by macrophages in bone marrow of knockout mice was significantly lower than control group ( < 0.05).
CONCLUSION
ABCC1/MRP1 transporter is a newly discovered IL-1β secretion pathway, which is expected to become a new target for solving clinical problems such as cytokine release syndrome.
Topics: Interleukin-1beta; Mice; Animals; Humans; Multidrug Resistance-Associated Proteins; Mice, Knockout; Macrophages; Down-Regulation; THP-1 Cells; Lipopolysaccharides
PubMed: 38926988
DOI: 10.19746/j.cnki.issn.1009-2137.2024.03.040 -
BMC Biotechnology Jun 2024Mammalian display is an appealing technology for therapeutic antibody development. Despite the advantages of mammalian display, such as full-length IgG display with...
BACKGROUND
Mammalian display is an appealing technology for therapeutic antibody development. Despite the advantages of mammalian display, such as full-length IgG display with mammalian glycosylation and its inherent ability to select antibodies with good biophysical properties, the restricted library size and large culture volumes remain challenges. Bxb1 serine integrase is commonly used for the stable genomic integration of antibody genes into mammalian cells, but presently lacks the efficiency required for the display of large mammalian display libraries. To increase the Bxb1 integrase-mediated stable integration efficiency, our study investigates factors that potentially affect the nuclear localization of Bxb1 integrase.
METHODS
In an attempt to enhance Bxb1 serine integrase-mediated integration efficiency, we fused various nuclear localization signals (NLS) to the N- and C-termini of the integrase. Concurrently, we co-expressed multiple proteins associated with nuclear transport to assess their impact on the stable integration efficiency of green fluorescent protein (GFP)-encoding DNA and an antibody display cassette into the genome of Chinese hamster ovary (CHO) cells containing a landing pad for Bxb1 integrase-mediated integration.
RESULTS
The nucleoplasmin NLS from Xenopus laevis, when fused to the C-terminus of Bxb1 integrase, demonstrated the highest enhancement in stable integration efficiency among the tested NLS fusions, exhibiting over a 6-fold improvement compared to Bxb1 integrase lacking an NLS fusion. Subsequent additions of extra NLS fusions to the Bxb1 integrase revealed an additional 131% enhancement in stable integration efficiency with the inclusion of two copies of C-terminal nucleoplasmin NLS fusions. Further improvement was achieved by co-expressing the Ran GTPase-activating protein (RanGAP). Finally, to validate the applicability of these findings to more complex proteins, the DNA encoding the membrane-bound clinical antibody abrilumab was stably integrated into the genome of CHO cells using Bxb1 integrase with two copies of C-terminal nucleoplasmin NLS fusions and co-expression of RanGAP. This approach demonstrated over 14-fold increase in integration efficiency compared to Bxb1 integrase lacking an NLS fusion.
CONCLUSIONS
This study demonstrates that optimizing the NLS sequence fusion for Bxb1 integrase significantly enhances the stable genomic integration efficiency. These findings provide a practical approach for constructing larger libraries in mammalian cells through the stable integration of genes into a genomic landing pad.
Topics: Animals; CHO Cells; Integrases; Cricetulus; Nuclear Localization Signals; Cell Nucleus; Serine; Green Fluorescent Proteins; Cricetinae; Xenopus laevis
PubMed: 38926833
DOI: 10.1186/s12896-024-00871-4 -
Journal of Cachexia, Sarcopenia and... Jun 2024Sarcopenia, a group of muscle-related disorders, leads to the gradual decline and weakening of skeletal muscle over time. Recognizing the pivotal role of...
BACKGROUND
Sarcopenia, a group of muscle-related disorders, leads to the gradual decline and weakening of skeletal muscle over time. Recognizing the pivotal role of gastrointestinal conditions in maintaining metabolic homeostasis within skeletal muscle, we hypothesize that the effectiveness of the myogenic programme is influenced by the levels of gastrointestinal hormones in the bloodstream, and this connection is associated with the onset of sarcopenia.
METHODS
We first categorized 145 individuals from the Emergency Room of Taipei Veterans General Hospital into sarcopenia and non-sarcopenia groups, following the criteria established by the Asian Working Group for Sarcopenia. A thorough examination of specific gastrointestinal hormone levels in plasma was conducted to identify the one most closely associated with sarcopenia. Techniques, including immunofluorescence, western blotting, glucose uptake assays, seahorse real-time cell metabolic analysis, flow cytometry analysis, kinesin-1 activity assays and qPCR analysis, were applied to investigate its impacts and mechanisms on myogenic differentiation.
RESULTS
Individuals in the sarcopenia group exhibited elevated plasma levels of glucagon-like peptide 1 (GLP-1) at 1021.5 ± 313.5 pg/mL, in contrast to non-sarcopenic individuals with levels at 351.1 ± 39.0 pg/mL (P < 0.05). Although it is typical for GLP-1 levels to rise post-meal and subsequently drop naturally, detecting higher GLP-1 levels in starving individuals with sarcopenia raised the possibility of GLP-1 influencing myogenic differentiation in skeletal muscle. Further investigation using a cell model revealed that GLP-1 (1, 10 and 100 ng/mL) dose-dependently suppressed the expression of the myogenic marker, impeding myocyte fusion and the formation of polarized myotubes during differentiation. GLP-1 significantly inhibited the activity of the microtubule motor kinesin-1, interfering with the translocation of glucose transporter 4 (GLUT4) to the cell membrane and the dispersion of mitochondria. These impairments subsequently led to a reduction in glucose uptake to 0.81 ± 0.04 fold (P < 0.01) and mitochondrial adenosine triphosphate (ATP) production from 25.24 ± 1.57 pmol/min to 18.83 ± 1.11 pmol/min (P < 0.05). Continuous exposure to GLP-1, even under insulin induction, attenuated the elevated glucose uptake.
CONCLUSIONS
The elevated GLP-1 levels observed in individuals with sarcopenia are associated with a reduction in myogenic differentiation. The impact of GLP-1 on both the membrane translocation of GLUT4 and the dispersion of mitochondria significantly hinders glucose uptake and the production of mitochondrial ATP necessary for the myogenic programme. These findings point us towards strategies to establish the muscle-gut axis, particularly in the context of sarcopenia. Additionally, these results present the potential of identifying relevant diagnostic biomarkers.
PubMed: 38926763
DOI: 10.1002/jcsm.13524 -
Nature Cell Biology Jun 2024Cargo translocation across membranes is a crucial aspect of secretion. In conventional secretion signal peptide-equipped proteins enter the endoplasmic reticulum (ER),...
Cargo translocation across membranes is a crucial aspect of secretion. In conventional secretion signal peptide-equipped proteins enter the endoplasmic reticulum (ER), whereas a subset of cargo lacking signal peptides translocate into the ER-Golgi intermediate compartment (ERGIC) in a process called unconventional protein secretion (UcPS). The regulatory events at the ERGIC in UcPS are unclear. Here we reveal the involvement of ERGIC-localized small GTPases, Rab1 (Rab1A and Rab1B) and Rab2A, in regulating UcPS cargo transport via TMED10 on the ERGIC. Rab1 enhances TMED10 translocator activity, promoting cargo translocation into the ERGIC, whereas Rab2A, in collaboration with KIF5B, regulates ERGIC compartmentalization, establishing a UcPS-specific compartment. This study highlights the pivotal role of ERGIC-localized Rabs in governing cargo translocation and specifying the ERGIC's function in UcPS.
PubMed: 38926505
DOI: 10.1038/s41556-024-01445-4