Biomedical subjects

Fu-Dong Shi

Publications and source records attributed to Fu-Dong Shi.

13 recordsLinked to original sources

PubMed2025

Gain-of-function PPM1D mutations attenuate ischemic stroke.

Identification of genetic aberrations in stroke, the second leading cause of death worldwide, is of paramount importance for understanding the disease pathogenesis and generating new therapies. Whole-genome sequencing from 10,241 ischemic stroke patients identified eight patients carrying gain-of-function mutations on coding variants in the protein phosphatase magnesium-dependent 1 δ (PPM1D) gene. Patients carrying PPM1D mutations exhibit better stroke-related clinical phenotypes, including improvements in peripheral inflammation, fibrinogen, low-density lipoprotein, cholesterol and plateletcrit level. Experimental brain ischemia in Ppm1d-deficient (Ppm1d-/-) mice resulted in enlarged lesions and pronounced neurological impairments. Spatial transcriptomics revealed a distinct Ppm1d-associated gene expression pattern, indicating disrupted endothelial homeostasis during ischemic brain injury. Proteomic analysis demonstrated that differentially expressed proteins in primary brain endothelial cells from Ppm1d-/- mice were significantly enriched in the peroxisome proliferator-activated receptors (PPARs)-mediated metabolic signaling. Mechanistically, Ppm1d deficiency promoted aberrant fatty acid β-oxidation and increased oxidative stress, which impaired endothelial cell function through the PPARα pathway. A small molecule, T2755, was identified to engage Trp427 and stabilize PPM1D, thereby mitigating ischemic brain injury in mice. Collectively, we find that PPM1D protects against ischemic brain injury and validates its pharmacological stabilizer T2755 as a promising therapy for ischemic stroke. Gain-of-function PPM1D mutations attenuate ischemic cerebral injury. Whole-genome sequencing data of 10,241 ischemic stroke patients from the Third Chinese National Stroke Registry (CNSR-III) identified eight patients with gain-of-function mutations in the protein phosphatase magnesium-dependent 1 δ (PPM1D) gene (17q23.2). These mutation carriers displayed improved peripheral inflammation, decreased fibrinogen, low-density lipoprotein, cholesterol and plateletcrit level. Ppm1d-deficient (Ppm1d-/-) mice exhibited exacerbated stroke outcomes, characterized by enlarged infarct volumes, disrupted cerebrovascular architecture, and enhanced neuro-inflammation. Mechanistically, Ppm1d deficiency induced the disturbance of endothelial fatty acid metabolism involving the PPARα pathway. Through integrated computational modeling, virtual screening, and in vitro validation, T2755 was identified as a small molecule PPM1D stabilizer. Pharmacological PPM1D stabilization with T2755 significantly attenuated ischemic brain injury in murine models.

Aged↗

PubMed2006

Cytokine-induced killer T cells kill immature dendritic cells by TCR-independent and perforin-dependent mechanisms.

Cytokine-induced killer (CIK) cells are ex vivo, expanded T cells with proven anticancer activity in vitro and in vivo. However, their functional properties with the exception of their cancer cell-killing activity are largely unclear. Here, we show that CIK T cells recognize dendritic cells (DC), and although mature DC (mDC) induce CIK T cells to produce IFN-gamma, immature DC (iDC) are killed selectively by them. Moreover, CIK T cell activation by mDC and their destruction of iDC are independent of the TCR. The cytotoxicity of CIK T cells to iDC is perforin-dependent. Our data have revealed an important regulatory role of CIK cells.

Animals↗

PubMed2006

Autoreactive T cells mediate NK cell degeneration in autoimmune disease.

Emerging evidence indicates that NK cells play an important and complex role in autoimmune disease. Humans with autoimmune diseases often have reduced NK cell numbers and compromised NK cell functions. Mechanisms underlying this NK cell degeneration and its biological significance are not known. In this study we show that, in an experimental model of human autoimmune myasthenia gravis induced by a self-Ag, the acetylcholine receptor, NK cells undergo proliferation during the initiation of autoimmunity, followed by significant degeneration associated with the establishment of the autoreactive T cell response. We show that NK cell degeneration was mediated by IL-21 derived from autoreactive CD4(+) T cells, and that acetylcholine receptor-immunized IL-21R-deficient mice, with competent NK cells, developed exacerbated autoimmunity. Thus, NK cell degeneration may serve as a means evolved by the immune system to control excessive autoimmunity.

Animals↗

PubMed2006

Do Th2 cells mediate the effects of glatiramer acetate in experimental autoimmune encephalomyelitis?

Mechanisms underlying the clinical benefits of glatiramer acetate (GA) for patients with multiple sclerosis (MS) remain elusive. A prevailing hypothesis is that GA can induce Th2-polarized T cells, which cross-recognize myelin-specific epitopes and can inhibit myelin-reactive autoaggression in Th1 T cells, a process referred to as 'bystander suppression.' To test whether the efficacy of GA is indeed mediated by Th2 T cells, we have utilized an animal model for MS: experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice. GA therapy conferred moderate protection from EAE. GA-reactive T cells from these mice were not Th2 polarized, and the Th1 cytokine reduction of myelin-reactive T cells in GA-treated mice was comparable to that in untreated control mice. Significantly, the protective effects of GA against EAE were also observed in IL-4-, IL-10-deficient and IL-4/IL-10 double-deficient mice. Similar to wild-type mice, GA therapy in IL-4- and IL-10-deficient mice was associated with diminished myelin-reactive T cell expansion and reduced production of myelin antigen-induced IFN-gamma and tumor necrosis factor-alpha. Thus, despite the absence of two prominent Th2 cytokines, IL-4 and IL-10, either alone or combined, GA was still beneficial in suppressing EAE. Our results caution against the notion that Th2 cells and bystander suppression account for the effect of GA on EAE and suggest that an alternative mechanism may operate in GA-treated MS patients.

Animals↗

PubMed2006

Reciprocal regulation between natural killer cells and autoreactive T cells.

The initiation and the progression of autoimmune diseases stem from complex interactions that involve cells of both the innate and the adaptive immune system. As we discuss here, natural killer (NK) cells, which are components of the innate immune system, can inhibit or promote the activation of autoreactive T cells during the initiation of autoimmunity. After they have been activated, autoreactive T cells contribute to the homeostatic contraction of NK-cell populations. The dynamic interaction between NK cells and autoreactive T cells might indicate the transition from the innate immune triggering of autoimmunity to the progressive phase of the disease. Understanding the mechanisms and signals that control the reciprocal regulation of NK cells and autoreactive T cells could have important implications for treatment in the clinic.

Animals↗

PubMed2006

The neuronal chemokine CX3CL1/fractalkine selectively recruits NK cells that modify experimental autoimmune encephalomyelitis within the central nervous system.

Leukocyte trafficking to the central nervous system (CNS), regulated in part by chemokines, determines severity of the demyelinating diseases multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). To examine chemokine receptor CX3CR1 in EAE, we studied CX3CR1(GFP/GFP) mice, in which CX3CR1 targeting by insertion of Green Fluorescent Protein (GFP) allowed tracking of CX3CR1+ cells in CX3CR1(+/GFP) animals and cells destined to express CX3CR1 in CX3CR1(GFP/GFP) knockouts. NK cells were markedly reduced in the inflamed CNS of CX3CR1-deficient mice with EAE, whereas recruitment of T cells, NKT cells and monocyte/macrophages to the CNS during EAE did not require CX3CR1. Impaired recruitment of NK cells in CX3CR1(GFP/GFP) mice was associated with increased EAE-related mortality, nonremitting spastic paraplegia and hemorrhagic inflammatory lesions. The absence of CD1d did not affect the severity of EAE in CX3CR1(GFP/GFP) mice, arguing against a role for NKT cells. Accumulation of NK cells in livers of wild-type (WT) and CX3CR1(GFP/GFP) mice with cytomegalovirus hepatitis was equivalent, indicating that CX3CL1 mediated chemoattraction of NK cells was relatively specific for the CNS. These results are the first to define a chemokine that governs NK cell migration to the CNS, and the findings suggest novel therapeutic manipulation of CX3CR1+ NK cells.

Animals↗

PubMed2006

Natural and adaptive immune cell-based therapies in autoimmunity.

Recent studies have raised great interest in the modulation of autoimmune responses by manipulation of immunoregulatory cells. Several lymphocyte subpopulations responsible for the induction and maintenance of immune tolerance have been extensively studied, and much has been learned about their properties. Lately, a series of attempts to harness the immunoregulatory activities of these cells for therapeutic purposes has proven successful in preclinical studies. The development of new strategies for the expansion of glycolipid-induced activation of NKT cells and antigen-specific regulatory T cells represent examples that have generated considerable interest and that are leading to the development of immunoregulatory cell-based approaches translating the findings from the bench to the bedside. This review highlights the advances, obstacles and limitations of these studies and critically discusses the most recent findings in this rapidly expanding field.

Animals↗

PubMed2006

Humoral immune response to p16, a cyclin-dependent kinase inhibitor in human malignancies.

The p16 protein is a cyclin-dependent kinase (CDK) inhibitor, which plays an important role in the regulation of the cell cycle by inactivating the cyclin-dependent kinase (CDK) that phosphorylates the retinoblastoma (Rb) protein. Overexpression of p16 protein has been found in many types of human malignancy. Autoantibody response to p16 in cancer has not been reported. This study determined the extent and frequency of autoantibodies to p16 in diverse malignancies. p16 recombinant protein was expressed in E. Coli BL21 (DE3) cells, and purified using GST fusion protein purification system. In further studies, p16 recombinant proteins were used as antigens in enzyme-linked immunoassay (ELISA) and Western blotting. Sera from 479 cancer patients and 82 normal individuals were analyzed. Autoantibodies to p16 were found in 11.7% in cancer, with significant difference from the normal individuals (p<0.05). The results in this study also showed that the frequency of antibodies to p16 is relatively higher in nasopharyngeal cancer (28.6%), breast cancer (17.1%) and hepatocellular carcinoma (HCC, 21.4%). Of the 56 ELISA positive sera with the anti-p16 antibodies, 85.7% (48/56) had positive reactions in Western blotting. The antigen-antibody absorption experiment was also performed to confirm the specificity of the anti-p16 antibody. In order to increase the frequency of antibody detection in cancer, a combination of three tumor-associated antigens (TAAs) p16, p53 and c-myc were used. Increased frequencies at p<0.01 were found for antibodies to p16 in breast, esophageal, and nasopharyngeal cancer as well as HCC. For antibodies to c-myc, increased frequencies at p<0.01 were found in breast, cervical, colorectal and lung cancer. For antibodies to p53, increased frequencies at p<0.01 were only found in breast cancer. With the successive addition of three TAAs, there was a stepwise increase of positive anti-body reaction up to 44% in breast cancer and 43% in nasopharyngeal cancer. In summary, the results in this study suggest that the combination of antibodies might acquire higher sensitivity for early cancer diagnosis. It is conceivable that auto-antibody profiles involving different panels or arrays of TAAs might be developed in the future and the results could be useful for cancer diagnosis.

Antibodies, Neoplasm↗

PubMed2005

Cooperation of invariant NKT cells and CD4+CD25+ T regulatory cells in the prevention of autoimmune myasthenia.

CD1d-restricted NKT cells and CD4+CD25+ regulatory T (Treg) cells are thymus-derived subsets of regulatory T cells that have an important role in the maintenance of self-tolerance. Whether NKT cells and Treg cells cooperate functionally in the regulation of autoimmunity is not known. We have explored this possibility in experimental autoimmune myasthenia gravis (EAMG), an animal model of human myasthenia gravis, induced by immunization of C57BL/6 mice with the autoantigen acetylcholine receptor. We have demonstrated that activation of NKT cells by a synthetic glycolipid agonist of NKT cells, alpha-galactosylceramide (alpha-GalCer), inhibits the development of EAMG. alpha-GalCer administration in EAMG mice increased the size of the Treg cell compartment, and augmented the expression of foxp3 and the potency of CD4+CD25+ cells to inhibit proliferation of autoreactive T cells. Furthermore, alpha-GalCer promoted NKT cells to transcribe the IL-2 gene and produce IL-2 protein. Depletion of CD25+ cells or neutralization of IL-2 reduced the therapeutic effect of alpha-GalCer in this model. Thus, alpha-GalCer-activated NKT cells can induce expansion of CD4+CD25+ Treg cells, which in turn mediate the therapeutic effects of alpha-GalCer in EAMG. Induced cooperation of NKT cells and Treg cells may serve as a superior strategy to treat autoimmune disease.

Animals↗

PubMed2005

Preferential humoral immune response in prostate cancer to cellular proteins p90 and p62 in a panel of tumor-associated antigens.

BACKGROUND: Cytoplasmic p90 autoantigen was recently cloned from a cDNA expression library using serum antibody from a cancer patient. The humoral immune response to p90 in prostate cancer and benign prostatic hyperplasia (BPH) was examined. METHODS: An antigenic fragment of recombinant p90 protein and several other tumor-associated antigens (TAAs) were used in ELISA and Western blotting to detect antibodies in sera from patients with prostate cancer, BPH, and other controls. RESULTS: Autoantibodies to p90 were detected in 30.8% of 133 prostate cancer patients versus 1.5% in 68 BPH patients. When a selected panel of six TAAs including p90 were used for immunoscreening, the cumulative positive reactions in prostate cancer sera reached 92.5%, significantly higher than in BPH and other control sera. Antibodies to p90 showed the highest frequency in prostate cancer (30.8%), followed by antibodies to p62 (22.6%). CONCLUSIONS: A panel of six selected TAAs was shown to have high sensitivity and specificity as immunodiagnostic markers in prostate cancer.

Antigens, Neoplasm↗

PubMed2005

Differential effects of IL-21 during initiation and progression of autoimmunity against neuroantigen.

The cytokine IL-21 is closely related to IL-2 and IL-15, a cytokine family that uses the common gamma-chain for signaling. IL-21 is expressed by activated CD4(+) T cells. We examined the role of IL-21 in the autoimmune disease experimental autoimmune encephalomyelitis (EAE), an animal model for human multiple sclerosis. IL-21 administration before induction of EAE with a neuroantigen, myelin oligodendrocyte glycoprotein peptide 35-55, and adjuvant enhanced the inflammatory influx into the CNS, as well as the severity of EAE. Autoreactive T cells purified from IL-21-treated mice transferred more severe EAE than did the control encephalitogenic T cells. No such effects were observed when IL-21 was administered after EAE progressed. Additional studies demonstrated that IL-21 given before the induction of EAE boosted NK cell function, including secretion of IFN-gamma. Depletion of NK cells abrogated the effect of IL-21. Therefore, IL-21, by affecting NK cells, has differential effects during the initiation and progression of autoimmune responses against neuroantigens.

Amino Acid Sequence↗

PubMed2005

Autoimmune response to anti-apoptotic protein survivin and its association with antibodies to p53 and c-myc in cancer detection.

Survivin, an inhibitor of apoptotic protein, is over-expressed in many cancers but not in normal differentiated adult tissues. Recently, antibodies to survivin have been demonstrated in patients with lung and colorectal cancer. Whether antibodies to survivin can be used as a marker for the diagnosis of cancer, and how antibody to survivin is related to antibodies against tumor suppressor protein p53 and oncoprotein c-myc remains to be evaluated. In the present study, the full-length recombinant proteins survivin, p53 and c-myc, were expressed and used as antigens in enzyme-linked immunosorbent assay (ELISA) and Western blot for the detection of antibodies to these three proteins. Sera from 1137 patients with 11 different types of cancer were analyzed. Antibodies to survivin were detected in 8.4% (96/1137), with a significant difference from the control groups consisting of normal individuals and autoimmune disease patients (p<0.05). Of 1137 cancer sera, 546 were also tested for the presence of antibodies to p53 and c-myc. Frequencies of antibodies to p53 and c-myc were 11.5 and 12.3%, respectively. Although antibodies to either one of three antigens do not reach levels of sensitivity, which could become routinely useful in diagnosis, it appears that there are different patterns of antibody frequency in individual cancer type. The results also indicated that when the presence of antibody to any one of these three antigens was considered, the cumulative frequency was increased to 27.3% (149/546) for the total group of cancer patients. It became apparent from our data that the combination of antibodies might acquire higher sensitivity.

Antibodies, Neoplasm↗

PubMed2003

Recursive partitioning as an approach to selection of immune markers for tumor diagnosis.

PURPOSE AND EXPERIMENTAL DESIGN: Cancer sera contain antibodies which react with a unique group of autologous cellular antigens called tumor-associated antigens (TAAs), but the low frequency of positive reactions against any individual antigen has precluded use of autoantibodies as useful diagnostic markers. With enzyme immunoassay, we examined antibody frequencies to a panel of seven TAAs, c-myc, cyclin B1, IMP1, Koc, p53, p62, and survivin, in 527 cancer patients (64 breast cancer patients, 45 colorectal cancers, 91 gastric cancers, 65 hepatocellular carcinomas, 56 lung cancers, and 206 prostate cancers), and 346 normals. We used recursive partitioning to assess whether we could accurately classify individuals as either cancer patients or normals on the basis of the profile of antibody reactivity to the seven TAAs for each individual. RESULTS: Recursive partitioning resulted in the selection of subsets of the seven-panel TAA, which differentiated between tumors and controls, and these subsets were unique to each cancer cohort. The classification trees had sensitivities ranging from 0.77 to 0.92 and specificities ranging from 0.85 to 0.91 in the cancer cohorts when normal means +2 SDs were used as standard cutoffs for immunoassay positivity. Antibody to cyclin B1 was the initial discriminating node for gastric and lung cancers, and for hepatocellular carcinoma, and was a subsequent discriminating node in all of the other cancer cohorts. c-myc was the initial discriminating node in breast cancer, p62 in prostate cancer, and IMP1 in colon cancer. Recursive partitioning demonstrated that no more than three of the seven TAAs were needed for any cancer cohort to arrive at these levels of sensitivity and specificity. CONCLUSIONS: This initial study shows that multiple antigen miniarrays can provide accurate and valuable tools for cancer detection and diagnosis. Performance of the miniarrays might be enhanced by other combinations of TAAs appropriately selected for different cancer cohorts.

Antibodies, Neoplasm↗