Publications by authors named "Andy P Xiang"

IL-10 regulatory B cells (Bregs) show great promise in treating graft-versus-host disease (GVHD), a life-threatening complication of post-hematopoietic stem cell transplantation. However, obtaining high-quality human IL-10 Bregs in vitro remains a challenge due to the lack of unique specific markers and the triggering of pro-inflammatory cytokine expression. Here, by uncovering the critical signaling pathways in Breg induction by mesenchymal stromal cells (MSCs), we first established an efficient Breg induction system based on MSCs and GSK-3β blockage (CHIR-99021), which had a robust capacity to induce IL-10 Bregs while suppressing tumor necrosis factor α (TNF-α) expression.

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  • - Despite advancements in medicine, hypertension treatment remains problematic, but recent research shows promise in using stem cell therapies, particularly mesenchymal stem cells (MSCs), for cardiovascular diseases.
  • - This study found that injecting human induced pluripotent stem cell-derived MSCs (hiPSC-MSCs) significantly reduced blood pressure in hypertensive rats and revealed that these cells accumulate in the spleen and may interact with the splenic nerve.
  • - The hiPSC-MSCs release glutamate, which activates the splenic sympathetic nerve, leading to increased norepinephrine release, enhancing choline acetyltransferase (ChAT) cell numbers, and ultimately contributing to lower blood pressure and reduced inflammation.
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  • Chemotherapy resistance, particularly to oxaliplatin, is a major challenge in treating gastric cancer, with unclear mechanisms behind this resistance.
  • Research demonstrated that mechanical signaling from the extracellular matrix plays a key role in developing oxaliplatin resistance in gastric cancer cells.
  • The study found that increased mitochondrial content in gastric cancer cells, derived from mesenchymal stromal cells, was linked to enhanced mitochondrial function and reduced mitophagy, contributing to resistance, and targeting the RhoA/ROCK1 pathway could help overcome this resistance.
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Study Question: What is the molecular landscape underlying the functional decline of human testicular ageing?

Summary Answer: The present study provides a comprehensive single-cell transcriptomic atlas of testes from young and old humans and offers insights into the molecular mechanisms and potential targets for human testicular ageing.

What Is Known Already: Testicular ageing is known to cause male age-related fertility decline and hypogonadism. Dysfunction of testicular cells has been considered as a key factor for testicular ageing.

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Treating Multiple sclerosis (MS), a well-known immune-mediated disease characterized by axonal demyelination, is challenging due to its complex causes. Naphthalenedione, present in numerous plants, is being explored as a potential medicine for MS due to its immunomodulatory properties. However, its effects on lymphocytes can vary depending on factors such as the specific compound, concentration, and experimental conditions.

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The essential role of U4 snRNP in pre-messenger RNA (mRNA) splicing has been well established. In this study, we utilized an antisense morpholino oligonucleotide (AMO) specifically targeting U4 snRNA to achieve functional knockdown of U4 snRNP in HeLa cells. Our results showed that this knockdown resulted in global intronic premature cleavage and polyadenylation (PCPA) events, comparable to the effects observed with U1 AMO treatment, as demonstrated by mRNA 3'-seq analysis.

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Leydig cell failure (LCF) caused by gene mutations leads to testosterone deficiency, infertility and reduced physical function. Adeno-associated virus serotype 8 (AAV8)-mediated gene therapy shows potential in treating LCF in the Lhcgr-deficient (Lhcgr) mouse model. However, the gene-treated mice still cannot naturally sire offspring, indicating the modestly restored testosterone and spermatogenesis in AAV8-treated mice remain insufficient to support natural fertility.

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Dysfunction of the sympathetic nervous system and increased epicardial adipose tissue (EAT) have been independently associated with the occurrence of cardiac arrhythmia. However, their exact roles in triggering arrhythmia remain elusive. Here, using an in vitro coculture system with sympathetic neurons, cardiomyocytes, and adipocytes, we show that adipocyte-derived leptin activates sympathetic neurons and increases the release of neuropeptide Y (NPY), which in turn triggers arrhythmia in cardiomyocytes by interacting with the Y1 receptor (Y1R) and subsequently enhancing the activity of the Na/Ca exchanger (NCX) and calcium/calmodulin-dependent protein kinase II (CaMKII).

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Adaptive metabolic responses and innate metabolites hold promising therapeutic potential for stroke, while targeted interventions require a thorough understanding of underlying mechanisms. Adiposity is a noted modifiable metabolic risk factor for stroke, and recent research suggests that it benefits neurological rehabilitation. During the early phase of experimental stroke, the lipidomic results showed that fat depots underwent pronounced lipolysis and released fatty acids (FAs) that feed into consequent hepatic FA oxidation and ketogenesis.

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  • This research focuses on the aging of skeletal muscle, which contributes to frailty and sarcopenia in older adults, affecting global health significantly.
  • The study analyzed over 90,000 single cells and nuclei from 17 donors to discover how muscle stem cells change with age, revealing distinct aging traits and alterations in muscle structure.
  • The findings include new insights into muscle regeneration, the role of immune cells in the aging muscle environment, and the launch of a comprehensive muscle aging resource for further research in humans and mice.
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Background: Testicular aging is associated with diminished fertility and certain age-related ailments, and effective therapeutic interventions remain elusive. Here, we probed the therapeutic efficacy of exosomes derived from human umbilical cord mesenchymal stem cells (hUMSC-Exos) in counteracting testicular aging.

Methods: We employed a model of 22-month-old mice and administered intratesticular injections of hUMSC-Exos.

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  • - Major depressive disorder (MDD) is a prevalent mental disorder with limited treatment options, and while mesenchymal stromal cells (MSCs) show promise, their mechanisms of action were not fully understood.
  • - Research using mouse models showed that MSCs improve symptoms of depression and anxiety by activating specific neurons in the brain, rather than reducing inflammation.
  • - The study identified a pathway where MSCs stimulate sensory neurons in the lungs, leading to increased serotonin release in the brain, suggesting a new treatment route for MDD through the "lung vagal-to-brain axis."
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Human midbrain dopaminergic progenitors (mDAPs) are one of the most representative cell types in both basic research and clinical applications. However, there are still many challenges for the preparation and quality control of mDAPs, such as the lack of standards. Therefore, the establishment of critical quality attributes and technical specifications for mDAPs is largely needed.

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'Human neural stem cells' jointly drafted and agreed upon by experts from the Chinese Society for Stem Cell Research, is the first guideline for human neural stem cells (hNSCs) in China. This standard specifies the technical requirements, test methods, test regulations, instructions for use, labelling requirements, packaging requirements, storage requirements, transportation requirements and waste disposal requirements for hNSCs, which is applicable to the quality control for hNSCs. It was originally released by the China Society for Cell Biology on 30 August 2022.

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  • People with weak immune systems are more likely to get sick from viruses like Epstein-Barr virus (EBV), which can cause serious lung infections.
  • In research with mice, scientists discovered that using special cells called mesenchymal stem cells (MSCs) can help treat pneumonia caused by EBV.
  • The study showed that these MSCs not only reduced lung damage but also helped control inflammation and changed how certain immune cells behaved, making the treatment promising for fighting similar infections in humans.
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Ferroptosis is a newly discovered form of iron-dependent oxidative cell death and drives the loss of neurons in spinal cord injury (SCI). Mitochondrial damage is a critical contributor to neuronal death, while mitochondrial quality control (MQC) is an essential process for maintaining mitochondrial homeostasis to promote neuronal survival. However, the role of MQC in neuronal ferroptosis has not been clearly elucidated.

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Hereditary primary hypogonadism (HPH), caused by gene mutation related to testosterone synthesis in Leydig cells, usually impairs male sexual development and spermatogenesis. Genetically corrected stem Leydig cells (SLCs) transplantation may provide a new approach for treating HPH. Here, a novel nonsense-point-mutation mouse model (Lhcgr ) is first generated based on a gene mutation relative to HPH patients.

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Background & Aims: Integrin αv (ITGAV, CD51) is regarded as a key component in multiple stages of tumor progression. However, the clinical failure of cilengitide, a specific inhibitor targeting surface CD51, suggests the importance of yet-unknown mechanisms by which CD51 promotes tumor progression.

Methods: In this study, we used several hepatocellular carcinoma (HCC) cell lines and murine hepatoma cell lines.

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Hyperhomocysteinemia (HHcy) plays a salient role in male infertility. However, whether HHcy interferes with testosterone production remains inconclusive. Here, we reported a lower serum testosterone level in HHcy mice.

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Chronic graft-versus-host disease (cGVHD) is a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Mature donor T cells within the graft contribute to severe damage of thymic epithelial cells (TECs), which are known as key mediators in the continuum of acute GVHD (aGVHD) and cGVHD pathology. Mesenchymal stromal cells (MSCs) are reportedly effective in the prevention and treatment of cGVHD.

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Functional depletion of the U1 small nuclear ribonucleoprotein (snRNP) with a 25 nt U1 AMO (antisense morpholino oligonucleotide) may lead to intronic premature cleavage and polyadenylation of thousands of genes, a phenomenon known as U1 snRNP telescripting; however, the underlying mechanism remains elusive. In this study, we demonstrated that U1 AMO could disrupt U1 snRNP structure both in vitro and in vivo, thereby affecting the U1 snRNP-RNAP polymerase II interaction. By performing chromatin immunoprecipitation sequencing for phosphorylation of Ser2 and Ser5 of the C-terminal domain of RPB1, the largest subunit of RNAP polymerase II, we showed that transcription elongation was disturbed upon U1 AMO treatment, with a particular high phosphorylation of Ser2 signal at intronic cryptic polyadenylation sites (PASs).

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Biomarkers of aging.

Sci China Life Sci

May 2023

Aging biomarkers are a combination of biological parameters to (i) assess age-related changes, (ii) track the physiological aging process, and (iii) predict the transition into a pathological status. Although a broad spectrum of aging biomarkers has been developed, their potential uses and limitations remain poorly characterized. An immediate goal of biomarkers is to help us answer the following three fundamental questions in aging research: How old are we? Why do we get old? And how can we age slower? This review aims to address this need.

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Down syndrome (DS) is the most common chromosomal abnormality in live-born infants and is caused by trisomy of chromosome 21. Most individuals with DS display craniofacial dysmorphology, including reduced sizes of the skull, maxilla, and mandible. However, the underlying pathogenesis remains largely unknown.

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