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Biomedical subjects

Min Gao

Publications and source records attributed to Min Gao.

At least 19 recordsLinked to original sources

Subcellular sirtuin signaling networks: pivotal regulators of cardiovascular homeostasis and remodeling.

Sirtuins represent a family of highly conserved enzymes, initially identified as Silent Information Regulator 2 (Sir2) in yeast, where they serve as fundamental determinants of longevity. Overexpression of Sir2 in yeast significantly extends lifespan, while its deletion leads to shortened longevity. In mammals, sirtuins (SIRT1-7) represent a conserved family of NAD+-dependent deacylases with diverse catalytic activities. While most members primarily function as deacetylases, SIRT4 exhibits mono-ADP-ribosylation activity, and SIRT5 uniquely targets negatively charged acyl groups, including lysine succinylation, malonylation, and glutarylation. These enzymes act as critical intracellular sensors and regulators widely distributed across diverse tissues. By targeting a broad array of protein substrates, they regulate core biological processes-including genomic stability, metabolism, inflammation, and stress responses. As cardiovascular diseases (CVDs) remain the primary cause of global mortality, driven by complex pathologies such as chronic inflammation and metabolic dysregulation, the sirtuin network has emerged as an indispensable regulator of cardiovascular health. This review systematically elucidates the pivotal roles of sirtuins in cardiovascular homeostasis. We provide an in-depth, subcellular perspective on how nuclear, cytoplasmic, and mitochondrial sirtuins synergistically protect against cardiovascular remodeling, atherosclerosis (AS), and heart failure (HF). Particular emphasis is placed on the molecular mechanisms modulating macrophage polarization and the mitigation of vascular inflammation via the NF-κB signaling pathway. Furthermore, we assess the therapeutic promise of caloric restriction (CR) and pharmacological activators, incorporating recent human clinical evidence. We propose a framework matching sirtuin-based interventions to disease tempo, advocating isoform and compartment-specific strategies for acute and chronic CVDs.

Sirtuins↗

Skin-innervating glutamatergic neurons modulate aging.

Peripheral nerves regulate skin homeostasis by secreting neurotransmitters, but their role during skin aging remains incompletely understood. Here, we report that cutaneous denervation accelerates skin aging, as evidenced by collagen reduction. Neurofilament heavy chain (Nefh) is decreased in aged skin and is predominantly expressed in vesicular glutamate transporter 2-positive (Vglut2+) skin-innervating glutamatergic neurons. Notably, dermal fibroblasts, the primary producers of collagen, frequently contact Nefh+ nerve fibers. Moreover, Nefh deletion in Vglut2+ glutamatergic neurons drives skin fibroblast senescence and collagen loss, whereas additional glutamate improves skin aging phenotypes. Mechanistically, cyclin-dependent kinase 5 (Cdk5) interacts with both Nefh and Vglut2 and maintains glutamate release and collagen homeostasis. Additionally, in skin fibroblasts, solute carrier family 1 member 3 (Slc1a3) governs the collagen-promoting and anti-senescence functions of glutamate. Together, these findings reveal Nefh-mediated glutamatergic neuromodulation of skin aging and provide therapeutic targets for aging-related skin disorders.

Animals↗

Evidence for a novel psoriasis susceptibility locus at 9q33-9q34 in Chinese Hans.

Psoriasis is a heterogeneous disease for which nine linkage loci (PSORS loci 1-5 and PSORS7-10) have been accepted by the Human Genome Nomenclature Committee and an additional 16 potential susceptibility loci have been reported so far. Our previous genome-wide scan in 61 Chinese Han psoriasis vulgaris families found two susceptibility loci at 6p21.3 and 4q31 and additional suggestive linkage evidence at other regions, including 9q33. In this follow-up study, the linkage evidence at 9q33 was further investigated using an expanded sample of 160 families and improved marker coverage. Our follow-up linkage analysis of the 160 families demonstrated strong linkage evidence (P < or = 0.000022) throughout a region between 133.38 and 146.23 cM with a maximum nonparametric linkage (NPL) score of 4.64 (P = 0.00000023) and a heterogeneity LOD (HLOD) score of 5.03 (alpha = 46%) at 142.39 cM near the marker D9S290. By stratifying the 160 families into the subtypes of 130 early-onset and 30 late-onset families, we revealed stronger linkage evidence in the early-onset psoriasis families with a maximum multipoint HLOD score of 6.48 (alpha = 58%) and a maximum NPL score of 4.69 (P = 0.00000012) near marker D9S290. Our follow-up study has confirmed a novel susceptibility locus at 9q33-34 for early-onset psoriasis in the Chinese population.

Age of Onset↗

Five novel mutations of RNA-specific adenosine deaminase gene with dyschromatosis symmetrica hereditaria.

Dyschromatosis symmetrica hereditaria (OMIM127400) is a rare autosomal dominant pigmentary genodermatosis caused by mutations in the RNA-specific adenosine deaminase (ADAR) gene. This study investigated 5 families and 3 sporadic patients with dyschromatosis symmetrica hereditaria in the Chinese Han population from Anhui province, China. By direct sequencing, 5 novel ADAR gene mutations (c.982C>T, c.1491insA, c.2568_2571delTAAC, c.2969C>G and c.3040G>T) and 3 mutations described previously (c.3203-2A>G, c.3247C>T and c.3286C>T) were identified, all of which were heterozygous. We reviewed a total of 48 mutations in the ADAR gene in patients with dyschromatosis symmetrica hereditaria by previous reports and speculated that the mutation hotspots on the ADAR gene might be located in exons 9-15. The tRNA-specific and double-stranded RNA adenosine deaminase domain is essential for the deaminase activity of the ADAR encoded protein.

Adenosine Deaminase↗

Kinase MEKK1 is required for CD40-dependent activation of the kinases Jnk and p38, germinal center formation, B cell proliferation and antibody production.

Mice lacking activity of the kinase MEKK1 ('Map3k1(deltaKD)' mice) have defective activation of the kinase Jnk and increased production of T helper type 2 cytokines after T cell receptor ligation. Here we show that Map3k1(deltaKD) mice had defective germinal center formation and diminished production of antibodies recognizing thymus-dependent antigens. Those defects were B cell intrinsic, as MEKK1 was necessary for CD40-mediated activation of the kinases Jnk and p38 and transcription factor c-Jun, as well as for expression of cyclin D2 and activation-induced deaminase. MEKK1 was recruited to CD40 and adaptor molecule TRAF2 after CD40 ligation, and Map3k1(deltaKD) B cells were hypoproliferative after CD40 stimulation. Our data emphasize that MEKK1 is an essential component of signaling cascades needed for thymus-dependent antigen-induced B cell proliferation and antibody production.

Animals↗

Follow-up analysis of PSORS9 in 151 Chinese families confirmed the linkage to 4q31-32 and refined the evidence to the families of early-onset psoriasis.

Psoriasis linkage to 4q28-32 (PSORS9) was initially identified by our genome-wide scan in 61 Chinese families and subsequently supported by a meta-analysis of five genome-wide linkage scans of European populations. In this study, we performed a follow-up analysis of PSORS9 using an additional 90 families and improved marker coverage. Joint analysis of all 151 families obtained significant linkage evidence (HLOD=4.53, nonparametric linkage (NPL)=4.03 (P=0.000003)) at the marker interval D4S2997-D4S3033, and the same was obtained for the analysis of the independent new families (HLOD=4.33, NPL=3.15 (P=0.00004)). The linkage evidences from the whole families and the new families exceeded the genome-wide criteria for significant linkage. Furthermore, by performing an ordered subset analysis using mean age at onset as a covariate, we demonstrated that evidence for linkage to PSORS9 is concentrated in the early-onset families and suggested that further study of PSORS9 should focus on early-onset patients. This finding is contradictory to what was found in the Icelandic population and, together with other linkage results, suggests that Chinese and European populations are genetically different for linkage to PSORS9, which may partially explain the influence of ethnic factors on the varying prevalence of psoriasis.

Age of Onset↗

Caffeic acid derivatives production by hairy root cultures of Echinacea purpurea.

Inoculation of leaf explants of Echinacea purpurea (Moench) with Agrobacterium rhizogenes induced hairy roots with the capacity to produce biologically active caffeic acid derivatives (CADs), especially cichoric acid. The kinetics of growth, the uptake of macronutrients, and the accumulation of CADs were investigated in heterotrophically cultured hairy roots for a 50 day period. A maximum of 12.2 g L(-1) dry biomass was achieved in MS nutrients supplemented with 30 g L(-1) sucrose on day 40. The mathematical relationship between hairy root growth and conductivity was established during the exponential phase in Erlenmeyer flasks. HPLC analyses of methanolic (0.1% phosphoric acid; 70:30, v/v) extracts from hairy roots revealed the presence of important CADs: cichoric acid (19.21 mg g(-1) dry biomass), caftaric acid (3.56 mg g(-1) dry biomass), and chlorogenic acid (0.93 mg g(-1) dry biomass). These results demonstrate that biotechnological production of CADs in hairy roots of E. purpurea is possible. Furthermore, these hairy root cultures offer, for the very first time, an excellent biological model to study the biosynthetic pathway of medicinally important CADs.

Butylamines↗

[Expressions of stromal cell-derived factor-1 and CXCR4 in endometrial carcinoma tissues and cell lines].

OBJECTIVE: To investigate the expressions of SDF-1 and CXCR4 in human endometrial carcinoma tissues. METHODS: SDF-1 and CXCR4 protein expression levels were detected by immunohistochemical staining in 26 cases of atypic hyperplasia endometrium,simple hyperplasia endometrium and normal endometrium and 44 cases of endometrial carcinoma tissues. RESULTS: Both SDF-1 mRNA and CXCR4 mRNA were expressed in Ishikawa, while no expression of SDF-1 mRNA was detected in HEC-1A. The rates of CXCR4 and SDF-1 protein expressions were 100% in glandular cells of human normal endometrial tissues, while 90.9% and 93.2% in glandular cells of endometrial carcinoma tissues. These immunoreactivities of SDF-1 and CXCR4 were significantly low in endometrial carcinoma tissues as compared with those in normal endometrium; and the intensities of immunohistochemical staining significantly decreasesd in immunoreactivity of SDF-1 and CXCR4 in low grade as compared with that in hight grade. CONCLUSION: SDF-1 and CXCR4 were expressed differently in endometrial cell lines, human normal endometrial tissues,and endometrial carcinoma tissues. As compared with normal endometrium ,these were significantly low levels expression of SDF-1 and CXCR4 in endometrial carcinoma tissues.

Adenocarcinoma↗

[Expression of estrogen receptor-related receptor alpha and estrogen receptor alpha in endometrial carcinoma and the primary investigation of their clinical significance].

OBJECTIVE: To explore the roles of estrogen receptor-related receptor (ERR) alpha and estrogen receptor alpha in endometrial carcinoma and their clinical values. METHODS: Thirty-five cases of endometrial carcinoma were examined by immunohistochemistry. Clinicopathologic features including FIGO stage, histological grade, myometrial invasion and nodal metastasis were reviewed. RESULTS: The expression rate of ERalpha in patients with FIGO stage I endometrial carcinoma was more than that in stage II-IV(P = 0.005). The expression rate of ERRalpha in endometrial carcinoma patients at FIGO stage I was lower than that at stages II-IV(P = 0.007). The percentage of patients at FIGO stageI or with G1-2 or myometrial invasion < 1/2 in ERalpha (+) and ERRalpha (-) groups was higher than that in ERalpha (-) and ERRalpha (+) groups(P = 0.000, P = 0.031 and P = 0.022). CONCLUSION: ERalpha may be a biomarker of good prognosis while ERRalpha may serve as a biomarker of poor prognosis in endometrial carcinoma. The combinative measure of ERalpha and ERRalpha may improve the prognostic value.

Adenocarcinoma↗

[Regulation of 17beta-E2 on the membrane estrogen receptor alpha].

OBJECTIVE: To investigate the regulation of 17beta-estradiol on the membrane estrogen receptor alpha. METHODS: The Ishikawa cells were treated with 10(-6) mol/L 17beta-estradiol for 0, 3, 10, 30 minutes and 2, 12, 48 hours, respectively. Another group of Ishikawa cells was treated with 10(-12) mol/L, 10(-10) mol/L, 10(-8) mol/L and 10(-6) mol/L 17beta-estradiol for 30 minutes, respectively. The cells were marked with anti-ERalpha and measured with FACS. RESULTS: The fluorescence intensity of mERalpha increased gradually with the application of estradiol. It reached the peak at the end of 30 minutes. Then it began to decrease gradually. When the cells were treated at low concentration of estradiol the fluorescence intensity of mERalpha was high, especially at 10(-10) mol/L estradiol. Then with the rise of the concentration, the fluorescence intensity decreased. CONCLUSION: The quantity of mERalpha reached the peak at the end of 30 minutes when treated with estradiol. Then it decreased gradually. When treated with estradiol at different concentrations, its quantity could reach the peak at physiological concentration.

Adenocarcinoma↗

A homogeneous, solid-phase assay for hepatitis C virus RNA-dependent RNA polymerase.

Discovery and development of effective antiviral agents to combat hepatitis C virus (HCV) is the focus of intensive research both in academia and in pharmaceutical companies. One of the HCV nonstructural proteins, NS5B (an RNA-dependent RNA polymerase), represents an attractive target in light of the clinical success of human immunodeficiency virus reverse transcriptase inhibitors. To identify and evaluate NS5B inhibitors, we developed a homogeneous, solid-phase, high-throughput biochemical assay for detecting NS5B enzymatic activity. In this assay, a biotinylated oligo(dT(12)) primer was immobilized onto streptavidin-coated scintillation proximity assay (SPA) beads, and after addition of homopolymeric A template, NS5B enzyme, and radiolabeled uridine 5'-triphosphate, the primer-dependent RNA synthesis occurred on beads. Optimization of the on-bead reaction resulted in the use of significantly less RNA template and NS5B enzyme while producing a faster steady state reaction rate compared to the solution-phase or off-bead SPA. The newly developed solid-phase assay is functionally comparable to the solution-phase assay as similar potencies of HCV NS5B inhibitors tested were obtained with the two assays. Furthermore, the solid-phase assay offers the advantage of delaying initiation, mimicking a physical preincubation step required for evaluating time-dependent inhibitors.

Antiviral Agents↗

In vitro propagation of an endangered medicinal plant Saussurea involucrata Kar. et Kir.

An efficient micropropagation system for Saussurea involucrata Kar. et Kir., an endangered Chinese medicinal plant, has been developed. Shoot organogenesis occurred from S. involucrata leaf explants inoculated on medium with appropriate supplements of plant growth regulators. 66.0% of shoot regeneration frequency and 5.2 shoots per leaf explant were achieved when cultured on a medium containing 10 microM 6-benzylaminopurine (BAP) and 2.5 microM 1-naphthaleneacetic acid (NAA). Shoot organogenesis was improved further when the leaf explants were pre-incubated at low temperature, and 80.6% of shoot regeneration frequency was recorded with 9.3 shoots per leaf explant at 4 degrees C by 5-day pretreatment period. Up to 87.0% of the regenerated shoots formed complete plantlets on a medium containing 2.5 microM indole-3-acetic acid (IAA) within 28 days, and 85.2% of the regenerated plantlets survived and grew vigorously in greenhouse condition. The phytochemical profile of the micropropagated plants was similar to that of wild plants. The regeneration protocol developed in this study provides a basis for germplasm conservation and for further investigation of medicinally active constituents of the elite medicinal plant.

Benzyl Compounds↗

Stromal cell-derived factor 1alpha stimulates human endometrial carcinoma cell growth through the activation of both extracellular signal-regulated kinase 1/2 and Akt.

OBJECTIVE: The aim of study was to investigate the proliferative effects of stromal cell-derived factor-1alpha (SDF-1alpha) on endometrial carcinomas cell lines with different estrogen receptors (ER) and PTEN protein profiles. METHODS: MTT assays was used to detect the proliferation of HEC-1A and Ishikawa cells, and Western blotted analysis was used to detect activation of Akt and ERK1/2 in both cell lines after exposure to various concentrations of SDF-1alpha, MAPK-specific inhibitor PD98059 or PI3K-specific inhibitor LY294002. RESULTS: Low concentrations of SDF-1alpha ( 50 ng/ml) induced proliferation in both cell lines. ERK1/2 was significantly activated for more than 2 h by SDF-1alpha at 20 ng/ml in HEC-1A cells, but not in Ishikawa cells. In contrast, Akt was significantly activated for over 2 h in Ishikawa cells but remained unchanged in HEC-1A cells. High concentrations of SDF-1alpha activated Akt and ERK1/2 pathways in both cell lines in a dose-dependent manner, which was primarily inhibited by LY294002 for pAkt and by PD98059 for pERK 1/2. CONCLUSIONS: SDF-1alpha could stimulate the cell proliferation of endometrial carcinoma with different expression status of ER and PTEN in vitro, likely through the activation of both Akt and ERK1/2 signaling pathways.

Cell Line, Tumor↗

Genetic susceptibility to ulcerative colitis in the Chinese Han ethnic population: association with TNF polymorphisms.

BACKGROUND: Tumor necrosis factor alpha (TNFalpha) is an important proinflammatory cytokine that has been implicated in the pathogenesis of inflammatory bowel disease (IBD). Recent studies have evaluated the role of TNF promoter polymorphisms in IBD, whereas the data are inconsistent. Trans-racial mapping in an ethnically distinct but homogenous population may help clarify these associations. We investigate the association between TNF promoter polymorphisms and susceptibility to ulcerative colitis (UC) in the Chinese Han ethnic population. METHODS: We studied 110 unrelated UC patients and 292 healthy controls from Zhejiang Province, China. Genotyping for 6 common TNF promoter polymorphisms (TNF -1031T/C, -863C/A, -857C/T, -380G/A, -308G/A, -238G/A) was carried out by polymerase chain reaction sequence-specific primers (PCR-SSP). RESULTS: TNF -308A was associated with disease (allele frequency patients 14.6% vs controls 8.9%, P = 0.02). TNF -857T was increased in patients but without statistical significance (allele frequency 17.3% vs 12.2%, P = 0.06). Haplotype analysis revealed 6 haplotypes including two (H5 and H3), which contained TNF -308A. H5 was associated with disease (haplotype frequency patients -12.3% vs controls 7.5%, P = 0.03). Of note the rare haplotype H3 has not previously been identified in Caucasian populations. Homozygosity for the haplotype H4 comprising the common alleles at each TNF promoter single-nucleotide polymorphism (SNP) was negatively associated with disease (patients vs controls 24.5% vs 34.9%, P < 0.05). CONCLUSIONS: We report the association with TNF -308A polymorphisms in Chinese patients with ulcerative colitis. The functional study in Chinese Han ethnic population is now required.

China↗

Two-step purification of scutellarin from Erigeron breviscapus (vant.) Hand. Mazz. by high-speed counter-current chromatography.

Scutellarin, a flavone glycoside, popularly applied for the treatment of cardiopathy, has been purified in two-step purification by high-speed counter-current chromatography (HSCCC) from Erigeron breviscapus (vant.) Hand. Mazz. (Deng-zhan-hua in Chinese), a well-known traditional Chinese medicinal plant for heart disease. Two solvent systems, n-hexane-ethyl acetate-methanol-acetic acid-water (1:6:1.5:1:4, v/v/v/v/v) and ethyl acetate-n-butanol-acetonitrile-0.1% HCl (5:2:5:10, v/v/v/v) were used for the two-step purification. The purity of the collected fraction of scutellarin was 95.6%. This study supplies a new alternative method for purification of scutellarin.

Apigenin↗

Identifying priorities in methodological research using ICD-9-CM and ICD-10 administrative data: report from an international consortium.

BACKGROUND: Health administrative data are frequently used for health services and population health research. Comparative research using these data has been facilitated by the use of a standard system for coding diagnoses, the International Classification of Diseases (ICD). Research using the data must deal with data quality and validity limitations which arise because the data are not created for research purposes. This paper presents a list of high-priority methodological areas for researchers using health administrative data. METHODS: A group of researchers and users of health administrative data from Canada, the United States, Switzerland, Australia, China and the United Kingdom came together in June 2005 in Banff, Canada to discuss and identify high-priority methodological research areas. The generation of ideas for research focussed not only on matters relating to the use of administrative data in health services and population health research, but also on the challenges created in transitioning from ICD-9 to ICD-10. After the brain-storming session, voting took place to rank-order the suggested projects. Participants were asked to rate the importance of each project from 1 (low priority) to 10 (high priority). Average ranks were computed to prioritise the projects. RESULTS: Thirteen potential areas of research were identified, some of which represented preparatory work rather than research per se. The three most highly ranked priorities were the documentation of data fields in each country's hospital administrative data (average score 8.4), the translation of patient safety indicators from ICD-9 to ICD-10 (average score 8.0), and the development and validation of algorithms to verify the logic and internal consistency of coding in hospital abstract data (average score 7.0). CONCLUSION: The group discussions resulted in a list of expert views on critical international priorities for future methodological research relating to health administrative data. The consortium's members welcome contacts from investigators involved in research using health administrative data, especially in cross-jurisdictional collaborative studies or in studies that illustrate the application of ICD-10.

Algorithms↗