Yan Li

Bio: Yan Li is an academic researcher from Xiamen University. The author has contributed to research in topics: Pathogenesis & Medicine. The author has an hindex of 7, co-authored 17 publications receiving 155 citations.

The Roles of Regulatory B Cells in Cancer

Abstract: Regulatory B cells (Bregs), a newly described subset of B cells, have been proved to play a suppressive role in immune system. Bregs can inhibit other immune cells through cytokines secretion and antigen presentation, which give them the role in the pathogenesis of autoimmune diseases and cancers. There are no clear criteria to identify Bregs; different markers were used in the different experimental conditions. Massive researches had described the functions of immune cells such as regulatory T cells (Tregs), dendritic cells (DCs), and B cells in the autoimmune disorder diseases and cancers. More and more researches focused on the roles of Bregs and the cytokines such as Interleukin-10 (IL-10) and transforming growth factor beta (TGF- β ) secreted by Bregs. The aim of this review is to summarize the characteristics of Bregs and the roles of Bregs in cancer.

The use of biologic therapies in the treatment of rheumatoid arthritis.

Abstract: The use of biologic agents has revolutionized the management of rheumatoid arthritis (RA) in the past two decades. These biologic agents directly target molecules and cells involved in the pathogenesis of RA. Biologic agents indeed lead to a better prognosis and clinical remission in patients with RA, especially in patients who are not well-controlled with traditional disease-modifying anti-rheumatic drugs (DMARDs). Currently, five TNF inhibitors (infliximab, etanercept, adalimumab, golimumab and certolizumab pegol), an IL-6 receptor antagonist (tocilizumab), an IL-1 receptor antagonist (anakinra), a B cell depleting agent (rituximab) and a T cell co-stimulation inhibitor (abatacept) have been approved for the treatment of RA. With the increased understanding of the pathogenic mechanisms of RA and advantages in manufacturing biotechnology of pharmaceutical companies, a series of novel biologic therapeutic approaches are being developed. In the present paper, we will summarize the biologic agents currently available to treat RA, and the prospective biologic therapies that might be used in the management of RA in future.

Reduced Activity of HDAC3 and Increased Acetylation of Histones H3 in Peripheral Blood Mononuclear Cells of Patients with Rheumatoid Arthritis.

Abstract: Aberrant histone acetylation and deacetylation are increasingly thought to play important roles in the pathogenesis of rheumatoid arthritis (RA). However, limited data from studies about the activity of histone deacetylases (HDACs) and histone acetyltransferase (HAT) in RA are controversial. Those conflicting results may be caused by sample size, medication, and age- and sex-matched controls. The aim of this study is to investigate the expression and activity of class I HDACs (1–3.8) and their effects on histone acetylation in peripheral blood mononuclear cells (PBMCs) from RA patients. The expression of class I HDACs in PBMCs from RA patients was decreased in both mRNA and protein levels in comparison with HCs. The nuclear HAT activities were dramatically increased. Further, we found HDAC3 activity to be the most significantly reduced in overall reduction of HDACs in the RA group. The extent of total histone H3, but not H4, acetylation in PBMCs from RA patients was increased compared to that in healthy controls (HCs) ( ). In RA PBMCs, the activity and expression of class I HDACs are decreased, which is accompanied with enhanced HAT activity. An altered balance between HDAC and HAT activity was found in RA PBMCs.

The deficiency of Gαq leads to enhanced T-cell survival.

Abstract: We have previously reported that Gαq, the α subunit of the Gq protein, had important roles in dendritic cell migration, B-cell survival and autoimmunity. In this study, we showed that the deficiency of Gαq led to enhanced T-cell survival. Cultured Gnaq(-/-) T cells exhibited survival advantages both in medium alone and in the presence of anti-CD3 stimulation. Gnaq(-/-) T cells still exhibited a survival advantage when they were cultured in the presence of interleukin (IL)-2 or IL-7. Gnaq(-/-) T cells were more resistant to activation-induced cell death (AICD) in vitro. The survival advantage of Gnaq(-/-) T cells was further confirmed by transferring T cells into syngeneic hosts in vivo. Gαq deficiency might promote T-cell survival by upregulated Bcl-xL expression and downregulated Fas and FasL expressions. Furthermore, upon T-cell receptor (TCR) ligation, Akt activity was increased in Gnaq(-/-) T cells in comparison with wild-type (WT) T cells. The survival advantage of Gnaq(-/-) T cells was significantly attenuated after adding Akt inhibitor. Taken together, our data demonstrated a negative role of Gαq in regulating T-cell survival.

Gαq Regulates the Development of Rheumatoid Arthritis by Modulating Th1 Differentiation.

Abstract: The Gαq-containing G protein, an important member of Gq/11 class, is ubiquitously expressed in mammalian cells. Gαq has been found to play an important role in immune regulation and development of autoimmune disease such as rheumatoid arthritis (RA). However, how Gαq participates in the pathogenesis of RA is still not fully understood. In the present study, we aimed to find out whether Gαq controls RA via regulation of Th1 differentiation. We observed that the expression of Gαq was negatively correlated with the expression of signature Th1 cytokine (IFN-γ) in RA patients, which suggests a negative role of Gαq in differentiation of Th1 cells. By using Gαq knockout (Gnaq-/-) mice, we demonstrated that loss of Gαq led to enhanced Th1 cell differentiation. Gαq negative regulated the differentiation of Th1 cell by modulating the expression of T-bet and the activity of STAT4. Furthermore, we detected the increased ratio of Th1 cells in Gnaq-/- bone marrow (BM) chimeras spontaneously developing inflammatory arthritis. In conclusion, results presented in the study demonstrate that loss of Gαq promotes the differentiation of Th1 cells and contributes to the pathogenesis of RA.

HLA-G: An Immune Checkpoint Molecule.

Abstract: HLA-G is a molecule that was first known to confer protection to the fetus from destruction by the immune system of its mother, thus critically contributing to fetal-maternal tolerance. The first functional finding constituted the basis for HLA-G research and can be summarized as such: HLA-G, membrane-bound or soluble, strongly binds its inhibitory receptors on immune cells (NK, T, B, monocytes/dendritic cells), inhibits the functions of these effectors, and so induces immune inhibition. HLA-G function may therefore be beneficial because when expressed by a fetus or a transplant it protects them from rejection, or deleterious because when expressed by a tumor, it also protects it from antitumor immunity. This is the primary HLA-G function: that of a checkpoint molecule. Great work has been done in the past years to characterize HLA-G itself, its regulation, its functions and mechanisms of action, and its pathological relevance. We will review this here, focusing on transplantation and oncology because these pathological contexts have been studied the most and also because they best represent the two opposite sides of HLA-G: beneficial to be promoted, or deleterious to be blocked.

One year in review 2017: pathogenesis of rheumatoid arthritis.

Abstract: Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease influenced by both genetic and environmental factors. It has been postulated that a high-risk genetic background, in combination with epigenetic marks and environmental exposures, leads to a cascade of events inducing synovitis and consequent destructive arthritis. The clinical picture of joint involvement in RA is the result of chronic inflammation of the synovium, characterised by interactions of resident cells such as fibroblast-like synoviocytes (FLS) with cells of the innate (e.g. macrophages, dendritic cells, mast cells and NK cells, neutrophils) and adaptive immune system (e.g. B and T lymphocytes). Currently, our understanding of the role of innate and adaptive immunity in the pathogenesis of RA is expanding. The concept of how immune responses contribute to the disease has dramatically evolved over the last 50 years. Shedding some light on the different aspects of RA pathogenesis will help to identify new targets for the development of disease-modifying therapies. Thus, in this review we report new insights in RA pathogenesis, resulting from a literature research date published in the last year.

One year in review 2018: pathogenesis of rheumatoid arthritis.

Abstract: Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that primarily affects joints. The several mechanisms involved in the development of the disease are not completely understood. It has been proposed that different environmental factors, such as cigarette smoking, occupational and atmospheric agents act as trigger stimuli for the development of RA in genetically predisposed individuals, leading to synovial hyperplasia and bone destruction. The initial disease stage of RA is associated with alteration of innate and adaptive immune system with consequent production of autoantibodies, targeting various molecules including modified self-epitopes. In the following stages of the disease, both the innate (e.g. dendritic cells, macrophages and neutrophils) and adaptive immune cells (e.g. B and T lymphocytes) contribute to the amplification and perpetuation of the chronic inflammatory state. The recognition of key cells, mediators and mechanisms implicated in the pathogenesis of RA could provide the basis for the development of new and precise disease-modifying anti-rheumatic drugs. Therefore, we reviewed the literature of the last year in order to find the new insights in RA pathogenesis.

IL-21: A Pleiotropic Cytokine with Potential Applications in Oncology

Abstract: Interleukin- (IL-) 21 is a pleiotropic cytokine that regulates the activity of both innate and specific immunity. Indeed, it costimulates T and natural killer (NK) cell proliferation and function and regulates B cell survival and differentiation and the function of dendritic cells. In addition, IL-21 exerts divergent effects on different lymphoid cell leukemia and lymphomas, as it may support cell proliferation or on the contrary induce growth arrest or apoptosis of the neoplastic lymphoid cells. Several preclinical studies showed that IL-21 has antitumor activity in different tumor models, through mechanism involving the activation of NK and T or B cell responses. Moreover, IL-21's antitumor activity can be potentiated by its combination with other immune-enhancing molecules, monoclonal antibodies recognizing tumor antigens, chemotherapy, or molecular targeted agents. Clinical phase I-II studies of IL-21 in cancer patients showed immune stimulatory properties, acceptable toxicity profile, and antitumor effects in a fraction of patients. In view of its tolerability, IL-21 is also suitable for combinational therapeutic regimens with other agents. This review will summarize the biological functions of IL-21, and address its role in lymphoid malignancies and preclinical and clinical studies of cancer immunotherapy.

Apoptosis Induction of Fibroblast-Like Synoviocytes Is an Important Molecular-Mechanism for Herbal Medicine along with its Active Components in Treating Rheumatoid Arthritis

Abstract: Rheumatoid arthritis (RA) is a known chronic autoimmune disease can cause joint deformity and even loss of joint function. Fibroblast-like synoviocytes (FLS), one of the main cell types in synovial tissues of RA patients, are key effector cells in the development of RA and are considered as promising therapeutic targets for treating RA. Herbal medicines are precious resources for finding novel agents for treating various diseases including RA. It is reported that induction of apoptosis in FLS is an important mechanism for the herbal medicines to treat RA. Consequently, this paper reviewed the current available references on pro-apoptotic effects of herbal medicines on FLS and summarized the related possible signal pathways. Taken together, the main related signal pathways are concluded as death receptors mediated apoptotic pathway, mitochondrial dependent apoptotic pathway, NF-κB mediated apoptotic pathways, mitogen-activated protein kinase (MAPK) mediated apoptotic pathway, endoplasmic reticulum stress (ERS) mediated apoptotic pathway, PI3K-Akt mediated apoptotic pathway, and other reported pathways such as janus kinase/signal transducers and activators of transcription (JAK-STAT) signal pathway. Understanding the apoptosis induction pathways in FLS of these herbal medicines will not only help clear molecular mechanisms of herbal medicines for treating RA but also be beneficial for finding novel candidate therapeutic drugs from natural herbal medicines. Thus, we expect the present review will highlight the importance of herbal medicines and its components for treating RA via induction of apoptosis in FLS, and provide some directions for the future development of these mentioned herbal medicines as anti-RA drugs in clinical.