Biomedical subjects

Haiyan Yu

Publications and source records attributed to Haiyan Yu.

12 recordsLinked to original sources

PubMed2026

Integrated multi-omics profiling identifies aging-related molecular signatures and convergent interferon signaling in systemic lupus erythematosus.

BACKGROUND: Systemic lupus erythematosus (SLE) is characterized by chronic immune activation and molecular alterations that overlap with aging-related biological processes. However, how these alterations are organized across molecular layers and whether they converge on shared regulatory networks remain incompletely understood. METHODS: We performed an integrative multi-omics analysis combining in-house proteomic and phosphoproteomic data from 130 patients with SLE and 90 healthy controls (HCs) and publicly available transcriptomic datasets comprising 1,461 SLE patients. Proteins and phosphorylation sites were annotated using established aging-related gene resources. Differential protein abundance and phosphorylation changes were analyzed across disease-status and disease-activity comparisons. Nominal P-value thresholds were used for exploratory feature selection, whereas FDR-adjusted P values were used to assess robustness after multiple-testing correction. Kinase-substrate enrichment, transcription factor annotation, and cell-type-resolved transcriptomic comparison were used to explore potential regulatory programs. RESULTS: We identified 128 nominally altered proteins annotated to aging-related biological processes, including genomic instability, mitochondrial dysfunction, and epigenetic alterations. Phosphoproteomic analysis revealed 36 nominally altered phosphorylation sites, including previously unreported sites in IFI16 (S153, S780) and PKCδ (S507, S664). Clustering analysis demonstrated heterogeneous protein co-regulation patterns across disease states. Kinase activity inference suggested altered activity of TBK1 and IKKβ. TF analysis further highlighted STAT1, RELA, and PML as potential central nodes within the inferred regulatory network. Notably, these multi-omic alterations were not randomly distributed but showed convergence toward shared signaling pathways, particularly those related to interferon responses. CONCLUSIONS: This integrative multi-omics study identifies inflammatory and interferon-dominated molecular alterations in SLE PBMCs that overlap with aging-related biological processes and converge on shared regulatory networks. These findings provide a hypothesis-generating framework for investigating the intersection between chronic immune activation and aging-related molecular remodeling in SLE.

Humans↗

PubMed2006

Muscle-specific overexpression of wild type and R225Q mutant AMP-activated protein kinase gamma3-subunit differentially regulates glycogen accumulation.

AMP-activated protein kinase (AMPK) is a heterotrimeric complex that works as an energy sensor to integrate nutritional and hormonal signals. The naturally occurring R225Q mutation in the gamma3-subunit in pigs is associated with abnormally high glycogen content in skeletal muscle. Because skeletal muscle accounts for most of the body's glucose uptake, and gamma3 is specifically expressed in skeletal muscle, it is important to understand the underlying mechanism of this mutation in regulating glucose and glycogen metabolism. Using skeletal muscle-specific transgenic mice overexpressing wild type gamma3 (WTgamma3) and R225Q mutant gamma3 (MUTgamma3), we show that both WTgamma3 and MUTgamma3 mice have 1.5- to 2-fold increases in muscle glycogen content. In WTgamma3 mice, increased glycogen content was associated with elevated total glycogen synthase activity and reduced glycogen phosphorylase activity, whereas alterations in activities of these enzymes could not explain elevated glycogen in MUTgamma3 mice. Basal, 5-aminoimidazole-AICAR- and phenformin-stimulated AMPKalpha2 isoform-specific activities were decreased only in MUTgamma3 mice. Basal rates of 2-DG glucose uptake were decreased in both WTgamma3 and MUTgamma3 mice. However, AICAR- and phenformin-stimulated 2-DG glucose uptake were blunted only in MUTgamma3 mice. In conclusion, expression of either wild type or mutant gamma3-subunit of AMPK results in increased glycogen concentrations in muscle, but the mechanisms underlying this alteration appear to be different. Furthermore, mutation of the gamma3-subunit is associated with decreases in AMPKalpha2 isoform-specific activity and impairment in AICAR- and phenformin-stimulated skeletal muscle glucose uptake.

AMP-Activated Protein Kinases↗

PubMed2006

Comparison of the HPLC method and FT-NIR analysis for quantification of glucose, fructose, and sucrose in intact apple fruits.

A rapid quantification method was developed and validated for simultaneous and nondestructive quantifying the constituent sugar concentrations of intact apples using Fourier transform near-infrared (FT-NIR) spectroscopy in diffuse reflectance mode. Multiplicative scatter correction (MSC), the second derivative of Savitsky-Golay, and mean centering were used as spectral preprocessing options. Calibration models were established by the partial least squares (PLS) regression analysis, and validation of the method was performed according to the high-performance liquid chromatography (HPLC) chromatographic method. Spectral range and the number of PLS factors were optimized for the lowest root-mean-square error of prediction (RMSEP) and correlation coefficient of determination (r). The best models showed satisfactory predictions as measured by the RMSEP and r values: glucose, 0.201 and 0.950; fructose, 0.298 and 0.968; sucrose, 0.335 and 0.969, respectively. FT-NIR analysis of constituent sugar concentrations in the intact apple form was found to be more flexible and much faster than performed with the HPLC method.

Analysis of Variance↗

PubMed2006

Ischemia impairs the association between connexin 43 and M3 subtype of acetylcholine muscarinic receptor (M3-mAChR) in ventricular myocytes.

We used Western blot analysis to examine the expression of connexin 43 and M2/M3 acetylcholine muscarinic receptors (mAChR) and their interaction in ventricular myocytes from control and the ischemic heart. We confirmed that the connexin 43 and M2/ M3-mAChR were expressed in ventricular myocytes. Moreover, we showed that M3-mAChR was expressed in non-glycosylated (72 kDa) and glycosylated forms (115 kDa). Immunostaining showed that connexin 43 is closely associated with M3-mAChR in parts of cell membranes of myocytes. Immunoprecipitation of lysate of cardiac myocytes with M2/M3-mAChR antibody pulled down a 44 kDa protein recognized by connexin 43 antibody. Ischemia increased the expression of M3-mAChR in myocytes. The ischemiainduced increase in the M3-mAChR expression was specific because ischemia did not affect the expression of M1, M2, M4 and M5- mAChR in the heart. On the other hand, ischemia decreased the expression of connexin 43 in myocardium. We also examined the effect of ischemia on the interaction between M2/M3-mAChR and connexin 43. Ischemia suppressed the association of M3-mAChR with connexin 43 but did not affect the association of connexin 43 with M2-mAChR. Administration of choline before ischemia not only partially restored the expression of connexin 43 but also attenuated the ischemia-induced suppression of the association between connexin 43 and M3-mAChR. We conclude that connexin 43 interacts with M2/M3-mAChR and that ischemia specifically impairs the association between M3-mAChR and connexin 43.

Animals↗

PubMed2006

Decreased expression of inhibitory SMAD6 and SMAD7 in keloid scarring.

Keloids are benign skin tumours occurring during wound healing in genetically predisposed patients. They are characterised by an abnormal deposition of extracellular matrix components, in particular collagen. There is evidence that transforming growth factor-beta (TGFbeta) is involved in keloid formation. SMAD proteins play a crucial role in TGFbeta signaling and in terminating the TGFbeta signal by a negative feedback loop through SMAD6 and 7. It is unclear how TGFbeta signaling is connected to the pathogenesis of keloids. Therefore, we investigated the expression of SMAD mRNA and proteins in keloids, in normal skin and in normal scars. Dermal fibroblasts were obtained from punch-biopsies of keloids, normal scars and normal skin. Cells were stimulated with TGFbeta1 and the expression of SMAD2, 3, 4, 6 and 7 mRNA was analysed by real time RT-PCR. Protein expression was determined by Western blot analysis. Our data demonstrate a decreased mRNA expression of the inhibitory SMAD6 and 7 in keloid fibroblasts as compared to normal scar (p<0.01) and normal skin fibroblasts (p<0.05). SMAD3 mRNA was found to be lower in keloids (p<0.01) and in normal scar fibroblasts (p<0.001) compared to normal skin fibroblasts. Our data showed for the first time a decreased expression of the inhibitory SMAD6 and SMAD7 in keloid fibroblasts. This could explain why TGFbeta signaling is not terminated in keloids leading to overexpression of extracellularmatrix in keloids. These data support a possible role of SMAD6 and 7 in the pathogenesis of keloids.

Blotting, Western↗

PubMed2006

Insulin-stimulated insulin receptor substrate-2-associated phosphatidylinositol 3-kinase activity is enhanced in human skeletal muscle after exercise.

Exercise increases skeletal muscle insulin action but the underlying mechanisms mediating this are equivocal. In mouse skeletal muscle, prior exercise enhances insulin-stimulated insulin receptor substrate-2 (IRS-2) signaling (Diabetes 2002;51:479-83), but it is unknown if this also occurs in humans. Hyperinsulinemic-euglycemic clamps were performed on 7 untrained males at rest and immediately after 60 minutes of cycling exercise at approximately 75% Vo2peak. Muscle biopsies were obtained at basal, immediately after exercise, and at 30 and 120 minutes of hyperinsulinemia. Insulin infusion increased (P < .05) insulin receptor tyrosine phosphorylation similarly in both the rest and exercise trials. Under resting conditions, insulin infusion resulted in a small, but non-statistically significant increase in IRS-2-associated phosphatidylinositol 3 (PI 3)-kinase activity over basal levels. Exercise per se decreased (P < .05) IRS-2-associated PI 3-kinase activity. After exercise, insulin-stimulated IRS-2-associated PI 3-kinase activity tended to increase at 30 minutes and further increased (P < .05) at 120 minutes when compared with the resting trial. Insulin increased (P < .05) Akt Ser473 and GSK-3alpha/beta Ser21/Ser9 phosphorylation in both trials, with the response tending to be higher in the exercise trial. In conclusion, in the immediate period after an acute bout of exercise, insulin-stimulated IRS-2 signaling is enhanced in human skeletal muscle.

Adult↗

PubMed2005

Studies of transforming growth factors beta 1-3 and their receptors I and II in fibroblast of keloids and hypertrophic scars.

Keloids are benign skin tumours occurring during wound healing in genetically predisposed patients. They are characterized by an abnormal deposition of extracellular matrix components, particularly collagen. There is uncertain evidence that transforming growth factor-beta (TGFss) is involved in keloid formation. Therefore we investigated the expression of TGFss1, 2 and 3 and their receptors in keloids, hypertrophic scars and normal skin. Dermal fibroblasts were obtained from punch biopsies of patients with keloids and hypertrophic scars and from normal skin of healthy individuals. Total RNA was isolated and the expression of TGFss1, 2 and 3 and of TGFss receptors I and II (TGFssRI and II) was analysed by real-time PCR using the Lightcycler technique. Our data demonstrate significantly lower TGFss2 mRNA expression in hypertrophic scar fibroblasts as compared with fibroblasts derived from keloids and normal skin (p<0.05). In contrast, TGFss3 mRNA expression was significantly lower in keloid fibroblasts in comparison with fibroblasts derived from hypertrophic scar and normal skin (p<0.01). TGFssRI mRNA expression was significantly decreased in hypertrophic scar fibroblasts (p<0.01) and TGFssRII mRNA expression was decreased in keloids compared with hypertrophic scar fibroblasts (p<0.001). The ratio of TGFssRI/TGFssRII expression was increased in keloids compared with hypertrophic scar and normal skin fibroblasts. As recently supposed, an increased TGFssRI/TGFssRII ratio could promote fibrosis. Therefore our data support a possible role of TGFssRI and TGFssRII in combination with a certain TGFss expression pattern as fibrosis-inducing factors in keloids.

Case-Control Studies↗

PubMed2004

Overexpression or ablation of JNK in skeletal muscle has no effect on glycogen synthase activity.

c-Jun NH(2)-terminal kinase (JNK) is highly expressed in skeletal muscle and is robustly activated in response to muscle contraction. Little is known about the biological functions of JNK signaling in terminally differentiated muscle cells, although this protein has been proposed to regulate insulin-stimulated glycogen synthase activity in mouse skeletal muscle. To determine whether JNK signaling regulates contraction-stimulated glycogen synthase activation, we applied an electroporation technique to induce JNK overexpression (O/E) in mouse skeletal muscle. Ten days after electroporation, in situ muscle contraction increased JNK activity 2.6-fold in control muscles and 15-fold in the JNK O/E muscles. Despite the enormous activation of JNK activity in JNK O/E muscles, contraction resulted in similar increases in glycogen synthase activity in control and JNK O/E muscles. Consistent with these findings, basal and contraction-induced glycogen synthase activity was normal in muscles of both JNK1- and JNK2-deficient mice. JNK overexpression in muscle resulted in significant alterations in the basal phosphorylation state of several signaling proteins, such as extracellular signal-regulated kinase 1/2, p90 S6 kinase, glycogen synthase kinase 3, protein kinase B/Akt, and p70 S6 kinase, in the absence of changes in the expression of these proteins. These data suggest that JNK signaling regulates the phosphorylation state of several kinases in skeletal muscle. JNK activation is unlikely to be the major mechanism by which contractile activity increases glycogen synthase activity in skeletal muscle.

Animals↗

PubMed2003

Cloning and characterization of mouse 5'-AMP-activated protein kinase gamma3 subunit.

Naturally occurring mutations in the regulatory gamma-subunit of 5'-AMP-activated protein kinase (AMPK) can result in pronounced pathological changes that may stem from increases in muscle glycogen levels, making it critical to understand the role(s) of the gamma-subunit in AMPK function. In this study we cloned the mouse AMPKgamma3 subunit and revealed that there are two transcription start sites, which result in a long form, gamma3L (AF525500) and a short form, gamma3S (AF525501). AMPKgamma3L is the predominant form in mouse and is specifically expressed in mouse skeletal muscle at the protein level. In skeletal muscle, AMPKgamma3 shows higher levels of expression in fast-twitch white glycolytic muscle (type IIb) compared with fast-twitch red oxidative glycolytic muscle (type IIa), whereas gamma3 is undetectable in soleus muscle, a slow-twitch oxidative muscle with predominantly type I fibers. AMPKgamma3 can coimmunoprecipititate with both alpha and beta AMPK subunits. Overexpression of gamma3S and gamma3L in mouse tibialis anterior muscle in vivo has no effect on alpha1 and alpha2 subunit expression and does not alter AMPKalpha2 catalytic activity. However, gamma3S and gamma3L overexpression significantly increases AMPKalpha1 phosphorylation and activity by approximately 50%. The increase in AMPKalpha1 activity is not associated with alterations in glycogen accumulation or glycogen synthase expression. In conclusion, the gamma3 subunit of AMPK is highly expressed in fast-twitch glycolytic skeletal muscle, and wild-type gamma3 functions in the regulation of alpha1 catalytic activity, but it is not associated with changes in muscle glycogen concentrations.

AMP-Activated Protein Kinases↗

PubMed2003

Phospholipase Cdelta1 is required for skin stem cell lineage commitment.

Phosphoinositide-specific phospholipase C (PLC) is a key enzyme in phosphoinositide turnover and is involved in a variety of physiological functions. Here we report that PLCdelta(1)-deficient mice undergo progressive hair loss in the first postnatal hair cycle. Epidermal hyperplasia was observed, and many hairs in the skin of PLCdelta(1)-deficient mice failed to penetrate the epidermis and became zigzagged owing to occlusion of the hair canal. Two major downstream signals of PLC, calcium elevation and protein kinase C activation, were impaired in the keratinocytes and skin of PLCdelta(1)-deficient mice. In addition, many cysts that had remarkable similarities to interfollicular epidermis, as well as hyperplasia of sebaceous glands, were observed. Furthermore, PLCdelta(1)-deficient mice developed spontaneous skin tumors that had characteristics of both interfollicular epidermis and sebaceous glands. From these results, we conclude that PLCdelta(1) is required for skin stem cell lineage commitment.

Animals↗

PubMed2002

5'-AMP-activated protein kinase activity and subunit expression in exercise-trained human skeletal muscle.

5'-AMP-activated protein kinase (AMPK) has been proposed to be a pivotal factor in cellular responses to both acute exercise and exercise training. To investigate whether protein levels and gene expression of catalytic (alpha(1), alpha(2)) and regulatory (beta(1), beta(2), gamma(1), gamma(2), gamma(3)) AMPK subunits and exercise-induced AMPK activity are influenced by exercise training status, muscle biopsies were obtained from seven endurance exercise-trained and seven sedentary young healthy men. The alpha(1)- and alpha(2)-AMPK mRNA contents in trained subjects were both 117 +/- 2% of that in sedentary subjects (not significant), whereas mRNA for gamma(3) was 61 +/- 1% of that in sedentary subjects (not significant). The level of alpha(1)-AMPK protein in trained subjects was 185 +/- 34% of that in sedentary subjects (P < 0.05), whereas the levels of the remaining subunits (alpha(2), beta(1), beta(2), gamma(1), gamma(2), gamma(3)) were similar in trained and sedentary subjects. At the end of 20 min of cycle exercise at 80% of peak O(2) uptake, the increase in phosphorylation of alpha-AMPK (Thr(172)) was blunted in the trained group (138 +/- 38% above rest) compared with the sedentary group (353 +/- 63% above rest) (P < 0.05). Acetyl CoA-carboxylase beta-phosphorylation (Ser(221)), which is a marker for in vivo AMPK activity, was increased by exercise in both groups but to a lower level in trained subjects (32 +/- 5 arbitrary units) than in sedentary controls (45 +/- 1 arbitrary units) (P < 0.01). In conclusion, trained human skeletal muscle has increased alpha(1)-AMPK protein levels and blunted AMPK activation during exercise.

AMP-Activated Protein Kinases↗

PubMed2002

Role of sterol regulatory element binding proteins in the regulation of Galpha(i2) expression in cultured atrial cells.

We have previously demonstrated that growth of embryonic chick atrial cells in medium supplemented with lipoprotein-depleted serum (LPDS) resulted in a coordinate increase in the expression of genes involved in the parasympathetic response of the heart (the M2 muscarinic receptor; the alpha-subunit of the heterotrimeric G protein, Galpha(i2); and the inward rectifying K+ channel protein, GIRK1) and a marked increase in the negative chronotropic response of atrial cells to muscarinic stimulation. In the present study, we demonstrate that regulation of Galpha(i2) promoter activity by LPDS is mediated by the binding of a sterol regulatory element binding protein (SREBP) to a sterol regulatory element (SRE) in the Galpha(i2) promoter. Deletion and point mutation of this putative SRE interfered with the regulation of the Galpha(i2) promoter by SREBP and LPDS. Furthermore gel shift assays demonstrated that point mutations in the putative Galpha(i2) SRE markedly inhibited the binding of purified SREBP to oligonucleotides containing the Galpha(i2) SRE sequence. The expression of a dominant-negative SREBP mutant interfered with LPDS stimulation of Galpha(i2) promoter activity. Finally, we demonstrate that SREBP-1 is markedly more potent than SREBP-2 for the stimulation of Galpha(i2) promoter activity, suggesting that SREBP1 may play a role in the regulation of Galpha(i2) expression. These are the first data to demonstrate SREBP regulation of a protein not involved in lipid homeostasis and suggest a new relationship between lipid metabolism and the parasympathetic response of the heart.

Animals↗