Publications by authors named "Danjun Ma"

Currently, engineered skin substitutes (ESS) are unable to regenerate cutaneous appendages. Recent studies have shown that skin-derived precursors (SKPs), which are extensively available, have the potential to induce hair follicle neogenesis. Here, we demonstrate that ESS consisting of culture-expanded SKPs and epidermal stem cells (Epi-SCs) reconstitute the skin with hair follicle regeneration after grafting into nude mice.

View Article and Find Full Text PDF

Follicle-stimulating hormone (FSH) is a pituitary glycoprotein that regulates follicle maturation through its binding to follicle-stimulating hormone receptor (FSHR). Endothelial cells express FSHR, but its exact role in endothelial cells remains unclear. Here we show that FSHR expression was detectable in human umbilical vein endothelial cells (HUVECs).

View Article and Find Full Text PDF

Dysregulation of the inflammatory response is a key driver of many debilitating and costly diseases including immune disorders, cancer, and infection. Pyroptosis is a highly inflammatory form of programmed cell death, triggered by various stimuli and meditated by the activation of inflammatory caspases. Pharmacologic agents that provide strategies to modulate pyroptosis for research and clinical practice are still very limited.

View Article and Find Full Text PDF

Recurrence and metastasis remain the major obstacles to successful treatment of hepatocellular carcinoma (HCC). Chromatin remodeling factor ARID2 is commonly mutated in HCC, indicating its important role in cancer development. However, its role in HCC metastasis is largely elusive.

View Article and Find Full Text PDF

Context: Obesity-related insulin resistance (OIR) is one of the main contributors to type 2 diabetes and other metabolic diseases. Protein kinases are implicated in insulin signaling and glucose metabolism. Molecular mechanisms underlying OIR involving global kinase activities remain incompletely understood.

View Article and Find Full Text PDF

Human hepatocyte-like cells (HLCs) derived from human pluripotent stem cells (hPSCs) promise a valuable source of cells with human genetic background, physiologically relevant liver functions, and unlimited supply. With over 10 years' efforts in this field, great achievements have been made. HLCs have been successfully derived and applied in disease modeling, toxicity testing and drug discovery.

View Article and Find Full Text PDF

DNA variants in the SLC16A11 coding region were identified to be strongly associated with type 2 diabetes (T2DM) in a Mexican population. Previous studies suggested that these variants disrupt SLC16A11 function and therefore proposed to revive SLC16A11 levels or activity to achieve therapeutic benefit. However, with knockout mouse models, here we show that Slc16a11 depletion has no significant metabolic defects.

View Article and Find Full Text PDF

Charcoal-stripped fetal bovine serum (CS-FBS) is commonly used to study androgen responsiveness and androgen metabolism in cultured prostate cancer (CaP) cells. Switching CaP cells from FBS to CS-FBS may reduce the activity of androgen receptor (AR), inhibit cell proliferation, or modulate intracellular androgen metabolism. The removal of proteins by charcoal stripping may cause changes in biological functions and has not yet been investigated.

View Article and Find Full Text PDF

Hepatocyte-like cells (HLCs) derived from human pluripotent stem cells (hPSCs) offer a promising cell resource for disease modeling and transplantation. However, differentiated HLCs exhibit an immature phenotype and comprise a heterogeneous population. Thus, a better understanding of HLC differentiation will improve the likelihood of future application.

View Article and Find Full Text PDF

Membrane proteins may act as transporters, receptors, enzymes, and adhesion-anchors, accounting for nearly 70% of pharmaceutical drug targets. Difficulties in efficient enrichment, extraction, and solubilization still exist because of their relatively low abundance and poor solubility. A simplified membrane protein extraction approach with advantages of user-friendly sample processing procedures, good repeatability and significant effectiveness was developed in the current research for enhancing enrichment and identification of membrane proteins.

View Article and Find Full Text PDF

Failure to properly repair damaged due to myocardial infarction is a major cause of heart failure. In contrast with adult mammals, zebrafish hearts show remarkable regenerative capabilities after substantial damage. To characterize protein dynamics during heart regeneration, we employed an HPLC-ESI-MS/MS (mass spectrometry) approach.

View Article and Find Full Text PDF

Objective: To provide a more global view of adipocyte changes in human insulin resistance by proteomics analyses.

Methods: Baseline biopsies of abdominal subcutaneous adipose tissue were obtained from 23 subjects without diabetes. Euglycemic clamps were used to divide subjects into an insulin-resistant group (IR, N = 10) and an insulin-sensitive (IS, N = 13) group, which were of similar age and gender but unequal adiposity (greater in IR).

View Article and Find Full Text PDF

Protein phosphatase 2A (PP2A) is one of the major serine/threonine phosphatases. We hypothesize that PP2A regulates signaling cascades in pancreatic β-cells in the context of glucose-stimulated insulin secretion (GSIS). Using co-immunoprecipitation (co-IP) and tandem mass spectrometry, we globally identified the protein interaction partners of the PP2A catalytic subunit (PP2Ac) in insulin-secreting pancreatic β-cells.

View Article and Find Full Text PDF

Insulin resistance and Type 2 diabetes are marked by an aberrant response in the insulin signaling network. The phosphoinositide-dependent serine/threonine kinase, Akt2, plays a key role in insulin signaling and glucose uptake, most notably within skeletal muscle. Protein-protein interaction regulates the functional consequence of Akt2 and in turn, Akt2's role in glucose uptake.

View Article and Find Full Text PDF

The two key steps for analyzing proteomic data generated by high-resolution MS are database searching and postprocessing. While the two steps are interrelated, studies on their combinatory effects and the optimization of these procedures have not been adequately conducted. Here, we investigated the performance of three popular search engines (SEQUEST, Mascot, and MS Amanda) in conjunction with five filtering approaches, including respective score-based filtering, a group-based approach, local false discovery rate (LFDR), PeptideProphet, and Percolator.

View Article and Find Full Text PDF

Unlabelled: Serine/threonine protein phosphatase 1 regulatory subunit 12A (PPP1R12A) modulates the activity and specificity of the catalytic subunit of protein phosphatase 1, regulating various cellular processes via dephosphorylation. Nonetheless, little is known about phosphorylation events controlled by PPP1R12A in skeletal muscle insulin signaling. Here, we used quantitative phosphoproteomics to generate a global picture of phosphorylation events regulated by PPP1R12A in a L6 skeletal muscle cell line, which were engineered for inducible PPP1R12A knockdown.

View Article and Find Full Text PDF

Insulin receptor substrate 1 (IRS1) is a key mediator of insulin signal transduction. Perturbations involving IRS1 complexes may lead to the development of insulin resistance and type 2 diabetes (T2D). Surprisingly little is known about the proteins that interact with IRS1 in humans under health and disease conditions.

View Article and Find Full Text PDF

The silks of arthropods have an elementary role in the natural history of the organisms that spin them, yet they are coded by rapidly evolving genes leading some authors to speculate that silk proteins are non-homologous proteins co-opted multiple times independently for similar functions. However, some general structural patterns are emerging. In this work we identified three major silk gland proteins using a combined biochemical, proteomic, next-generation sequencing and bioinformatic approach.

View Article and Find Full Text PDF

Mineral dust-induced gene (mdig) had been linked to the development of human lung cancers associated with environmental exposure to mineral dust, tobacco smoke or other carcinogens. In the present studies, we demonstrated that the overexpression of mdig in A549 adenocarcinomic human alveolar type II epithelial cells decreases the heterochromatin conformation of the cells and de-represses the transcription of genes in the tandemly repeated DNA regions. Although mdig can only cause a marginal decrease of the total histone H3 lysine 9 trimethylation (H3K9me3), a significant reduction of H3K9me3 in the promoter region of H19, the paternally imprinted but maternally expressed gene transcribing a large intergenic non-coding RNA (lincRNA), was observed in the cells with mdig overexpression.

View Article and Find Full Text PDF

Oxythiamine (OT), an analogue of anti-metabolite, can suppress the nonoxidative synthesis of ribose and induce cell apoptosis by causing a G1 phase arrest in vitro and in vivo. However, the molecular mechanism remains unclear yet. In the present study, a quantitative proteomic analysis using the modified SILAC method (mSILAC) was performed to determine the effect of metabolic inhibition on dynamic changes of protein expression in MIA PaCa-2 cancer cells treated with OT at various doses (0 μM, 5 μM, 50 μM and 500 μM) and time points (0 h, 12 h and 48 h).

View Article and Find Full Text PDF

The secretory pathway of eukaryotic cells packages cargo proteins into COPII-coated vesicles for transport from the endoplasmic reticulum (ER) to the Golgi. We now report that complete genetic deficiency for the COPII component SEC24A is compatible with normal survival and development in the mouse, despite the fundamental role of SEC24 in COPII vesicle formation and cargo recruitment. However, these animals exhibit markedly reduced plasma cholesterol, with mutations in Apoe and Ldlr epistatic to Sec24a, suggesting a receptor-mediated lipoprotein clearance mechanism.

View Article and Find Full Text PDF

Mechanism underlying smoke-induced loss of bone mass is unknown. In this study, we hypothesized that protein signals induced by smoking in bone marrow may be associated with the loss of bone mass. Using a proteomics approach, we identified 38 proteins differentially expressed in bone marrow cells from low-density lipoprotein receptor-related protein 5 (Lrp5) mice exposed to cigarette smoking.

View Article and Find Full Text PDF

Protein phosphatase 1 (PP1) is one of the major phosphatases responsible for protein dephosphorylation in eukaryotes. So far, only few specific phosphorylation sites of PP1 regulatory subunit 12A (PPP1R12A) have been shown to regulate the PP1 activity. The effect of insulin on PPP1R12A phosphorylation is largely unknown.

View Article and Find Full Text PDF

Objectives: Novel quantitative proteomic approaches were used to study the effects of inhibition of glycogen phosphorylase on proteome and signaling pathways in MIA PaCa-2 pancreatic cancer cells.

Methods: We performed quantitative proteomic analysis in MIA PaCa-2 cancer cells treated with a stratified dose of CP-320626 (5-chloro-1H-indole-2-carboxylic acid [1-(4-fuorobenzyl)-2-(4-hydroxypiperidin-1-yl)-2 oxoethyl] amide) (25, 50, and 100 μM). The effect of metabolic inhibition on cellular protein turnover dynamics was also studied using the modified SILAC (stable isotope labeling with amino acids in cell culture) method.

View Article and Find Full Text PDF

MicroRNAs (miRNAs) play an important regulatory role in breast tumorigenesis. Previously, we found that let-7 miRNAs were downregulated significantly in formalin-fixed paraffin-embedded (FFPE) breast cancer tissues. In this study, we further found that endogenous levels of let-7b and let-7i miRNAs are inversely correlated with levels of estrogen receptor (ER)-a36, a new variant of ER-α66, in the FFPE tissue set.

View Article and Find Full Text PDF

Synopsis of recent research by authors named "Danjun Ma"

  • - Danjun Ma's recent research focuses on regenerative medicine, particularly in skin and hair follicle regeneration, as well as the exploration of underlying mechanisms in diseases such as cancer, obesity, and type 2 diabetes, using innovative methodologies such as engineered skin substitutes and proteomics.
  • - Key findings include the successful demonstration of engineered skin substitutes that promote hair follicle regeneration, as well as identifying critical roles of hormones like follicle-stimulating hormone in endothelial cell migration and abnormal kinase activities in obesity-related insulin resistance.
  • - Ma's studies also highlight significant molecular interactions in conditions like hepatocellular carcinoma metastasis and type 2 diabetes, revealing potential therapeutic targets, as well as advancements in cell differentiation techniques using human pluripotent stem cells.