Publications by authors named "Zu-Xi Yu"

Cytokine-mediated STAT5 protein activation is vital for lymphocyte development and function. In vitro tyrosine phosphorylation of a C-terminal tyrosine is critical for activation of STAT5A and STAT5B; however, the importance of STAT5 tyrosine phosphorylation in vivo has not been assessed. Here we generate Stat5a and Stat5b tyrosine-to-phenylalanine mutant knockin mice and find they have greatly reduced CD8 T-cell numbers and profoundly diminished IL-2-induced proliferation of these cells, and this correlates with reduced induction of Myc, pRB, a range of cyclins and CDKs, and a partial G1→S phase-transition block.

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In hypoxic and pseudohypoxic rodent models of pulmonary hypertension (PH), hypoxia-inducible factor (HIF) inhibition attenuates disease initiation. However, HIF activation alone, due to genetic alterations or use of inhibitors of prolyl hydroxylase domain (PHD) enzymes, has not been definitively shown to cause PH in humans, indicating the involvement of other mechanisms. Given the association between endothelial cell dysfunction and PH, the effects of pseudohypoxia and its underlying pathways were investigated in primary human lung endothelial cells.

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  • Septic shock leads to increased end-diastolic volume (EDV) and decreased ejection fraction in survivors, unlike nonsurvivors, whose EDV does not increase due to more severe diastolic dysfunction early in the condition.* -
  • In a study with beagles, findings indicate that septic animals experienced significant heart issues, including wall edema and thinning, resulting in decreased heart performance, particularly in nonsurvivors during the initial phase of sepsis.* -
  • The research suggests that cardiac dysfunction during sepsis is connected to microvascular injury and edema, with important implications for understanding heart changes and recovery in septic patients.*
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  • The enzyme ACOD1 is key in producing itaconate in immune cells, which may help regulate immune responses in lupus.
  • In a mouse model of lupus, ACOD1 knockout led to worsened disease symptoms, including increased inflammation and kidney damage compared to normal mice.
  • Itaconate levels were found to be lower in lupus patients than in healthy individuals, suggesting its potential use as a therapeutic target for autoimmune diseases.
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  • Pulmonary arterial hypertension (PAH) is a serious lung condition caused by changes in small blood vessels that lead to increased pressure in the pulmonary artery, and this is often linked to problems in the cells lining these vessels.
  • A key factor, DLL4, helps maintain healthy blood vessels through NOTCH1 signaling, and its inhibition is connected to the advancement of PAH, but the exact process is not fully understood.
  • Research indicates that restoring DLL4/NOTCH1 signaling or inhibiting the AKT pathway can help reverse harmful changes in the blood vessels seen in PAH, offering potential treatment strategies using compounds like leniolisib.
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  • Septic shock causes significant cardiac dysfunction in both humans and animal models, characterized by increased biventricular end diastolic volume and decreased ejection fraction, with these abnormalities developing over the course of two days and generally reversing by day ten.
  • In a study involving purpose-bred beagles, septic animals showed greater left ventricular wall edema and dysfunction compared to controls, with non-survivors displaying more severe changes in cardiac function and size.
  • The differential changes in cardiac volume and function between survivors and non-survivors suggest that septic shock impacts heart performance significantly, but the exact mechanisms behind these differences remain unclear.
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Cellular therapies with cardiomyocytes produced from induced pluripotent stem cells (iPSC-CMs) offer a potential route to cardiac regeneration as a treatment for chronic ischemic heart disease. Here, we report successful long-term engraftment and in vivo maturation of autologous iPSC-CMs in two rhesus macaques with small, subclinical chronic myocardial infarctions, all without immunosuppression. Longitudinal positron emission tomography imaging using the sodium/iodide symporter (NIS) reporter gene revealed stable grafts for over 6 and 12 months, with no teratoma formation.

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Pulmonary arterial hypertension (PAH) is a progressive cardiopulmonary disease characterized by pathologic vascular remodeling of small pulmonary arteries. Endothelial dysfunction in advanced PAH is associated with proliferation, apoptosis resistance, and endothelial to mesenchymal transition (EndoMT) due to aberrant signaling. DLL4, a cell membrane associated NOTCH ligand, plays a pivotal role maintaining vascular integrity.

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Objective: The Krebs cycle enzyme Aconitate Decarboxylase 1 (ACOD1) mediates itaconate synthesis in myeloid cells.. Previously, we reported that administration of 4-octyl itaconate abrogated lupus phenotype in mice.

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Rationale: Serum amyloid A (SAA) is bound to high-density lipoproteins (HDL) in blood. Although SAA is increased in the blood of patients with asthma, it is not known whether this modifies asthma severity.

Objective: We sought to define the clinical characteristics of patients with asthma who have high SAA levels and assess whether HDL from SAA-high patients with asthma is proinflammatory.

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Very-long-chain polyunsaturated fatty acids (VLCPUFAs; C24-38) constitute a unique class of PUFA that have important biological roles, but the lack of a suitable dietary source has limited research in this field. We produced an n-3 C24-28-rich VLCPUFA-oil concentrated from fish oil to study its bioavailability and physiological functions in C57BL/6J mice. The serum and retinal C24:5 levels increased significantly compared to control after a single-dose gavage, and VLCPUFAs were incorporated into the liver, brain, and eyes after 8-week supplementation.

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The IL-2 receptor α chain (IL-2Rα/CD25) is constitutively expressed on double-negative (DN2/DN3 thymocytes and regulatory T cells (T) but induced by IL-2 on T and natural killer (NK) cells, with expression regulated by a STAT5-dependent super-enhancer. We investigated CD25 regulation and function using a series of mice with deletions spanning STAT5-binding elements. Deleting the upstream super-enhancer region mainly affected constitutive CD25 expression on DN2/DN3 thymocytes and T, with these mice developing autoimmune alopecia, whereas deleting an intronic region decreased IL-2-induced CD25 on peripheral T and NK cells.

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Lymphangioleiomyomatosis (LAM) is a multisystem disease affecting primarily women, characterised in the lung by proliferation of LAM cells, abnormal smooth muscle-like cells with dysfunctional tuberous sclerosis complex genes. This dysfunction results in activation of mechanistic target of rapamycin (mTOR), leading to LAM cell proliferation. Sirolimus (rapamycin) is the only United States Food and Drug Administration-approved treatment for pulmonary LAM, resulting in decreased LAM cell growth/size and stabilised lung function [1].

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Arginase 1 (Arg1), the enzyme catalyzing the conversion of arginine to ornithine, is a hallmark of IL-10-producing immunoregulatory M2 macrophages. However, its expression in T cells is disputed. Here, we demonstrate that induction of Arg1 expression is a key feature of lung CD4 T cells during mouse in vivo influenza infection.

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Engineering of myocardial tissues has become a promising therapeutic strategy for treating myocardial infarction (MI). However, a significant challenge remains in generating clinically relevant myocardial tissues that possess native microstructural characteristics and fulfill the requirements for implantation within the human body. In this study, a thick 3D myocardial construct with anisotropic myofibers and perfusable branched vascular channels is created with clinically relevant dimensions using a customized beam-scanning stereolithography printing technique.

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Article Synopsis
  • Persistent skin inflammation leads to psoriasis and related health issues, with omega-3 polyunsaturated fatty acids (PUFAs) like EPA and DHA potentially playing a role in reducing inflammation.
  • A study was conducted using a mouse model to compare the effects of EPA and DHA over 12 weeks on psoriasis-like skin inflammation, focusing on how these substances affect inflammatory markers and lipid mediators.
  • Results showed that DHA treatment was more effective in reducing inflammation and modifying specific immune responses compared to EPA, suggesting that DHA might be the preferred option for managing psoriasis.
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Arginine-specific mono-ADP-ribosylation is a reversible post-translational modification; arginine-specific, cholera toxin-like mono-ADP-ribosyltransferases (ARTCs) transfer ADP-ribose from NAD to arginine, followed by cleavage of ADP-ribose-(arginine)protein bond by ADP-ribosylarginine hydrolase 1 (ARH1), generating unmodified (arginine)protein. ARTC1 has been shown to enhance tumorigenicity as does deficiency. In this study, -KO and -double-KO mice showed decreased spontaneous tumorigenesis and increased age-dependent, multi-organ inflammation with upregulation of pro-inflammatory cytokine TNF- .

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Aims: Patients with ( ) deficiency exhibit stress-induced childhood-onset neurodegeneration with ataxia and seizures (CONDSIAS). ARH3 degrades protein-linked poly(ADP- ribose) (PAR) synthesized by poly(ADP-ribose)polymerase (PARP)-1 during oxidative stress, leading to cleavage of the ADP-ribose linked to protein. deficiency leads to excess accumulation of PAR, resulting in PAR-dependent cell death or parthanatos.

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ADP-ribosylation is a reversible reaction with ADP-ribosyltransferases catalyzing the forward reaction and ADP-ribose-acceptor hydrolases (ARHs) hydrolyzing the ADP-ribose acceptor bond. ARH2 is a member of the 39-kDa ARH family (ARH1-3), which is expressed in heart and skeletal muscle. ARH2 failed to exhibit any in vitro enzymatic activity.

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Both monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) play important roles in lipid metabolism, and diets enriched with either of these two fatty acids are associated with decreased cardiovascular risk. Conventional soybean oil (CSO), a common food ingredient, predominantly contains linoleic acid (LA; C18:2), a n-6 PUFA. Recently, a modified soybean oil (MSO) enriched in oleic acid (C18:1), a n-9 MUFA, has been developed, because of its improved chemical stability to oxidation.

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Objective: Itaconic acid, a Krebs cycle-derived immunometabolite, is synthesized by myeloid cells in response to danger signals to control inflammasome activation, type I interferon (IFN) responses, and oxidative stress. As these pathways are dysregulated in systemic lupus erythematosus (SLE), we investigated the role of an itaconic acid derivative in the treatment of established murine lupus.

Methods: Female (NZW × NZB)F lupus-prone mice were administered 4-octyl itaconate (4-OI) or vehicle starting after clinical onset of disease (30 weeks of age) for 4 weeks (n = 10 mice /group).

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Lysyl oxidase (LOX) is a copper-binding enzyme that cross-links elastin and collagen. The dominant LOX variation contributes to familial thoracic aortic aneurysm. Previously reported murine Lox mutants had a mild phenotype and did not dilate without drug-induced provocation.

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Williams−Beuren syndrome (WS) results from the deletion of 25−27 coding genes, including elastin (ELN), on human chromosome 7q11.23. Elastin provides recoil to tissues; emphysema and chronic obstructive pulmonary disease have been linked to its destruction.

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Background: Williams Beuren syndrome (WBS) is a recurrent microdeletion disorder that removes one copy of elastin (), resulting in large artery vasculopathy. Early stenosis of the pulmonary vascular tree is common, but few data are available on longer-term implications of the condition.

Methods: Computed tomography (CT) angiogram ( = 11) and echocardiogram ( = 20) were performed in children with WBS aged 3.

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