IL-34 a Newly Discovered Cytokine

Abstract

In this study we describe some biological effects of IL-34, a newly discovered cytokine. We show that 11-34 stimulates monocyte cell viability and directly modulates the number and function of monocytes and regulates myeloid cell growth and differentiation. Moreover, since IL-34 in mice is involved in osteoporosis, an antagonist of this cytokine could be beneficial for the treatment of this disease.Cytokines are immune-regulatory proteins (1-4) and they induce inflammation in vivo, based on recruitment of white blood cell population (5-7). These cytokines include IL-2, IL-4, IL-7, IL-9, IL-ll, IL-12, IL-13, IL-15 ... .IL-35 and Colony Stimulating Factors (CSFs) and many others. They are multifunctional proteins which have a role in both innate and adaptive immune responses (8-13) with an effect on proliferation, differentiation, inhibition, apoptosis and chemoattraction (14-16). In addition, cytokines are involved in and mediate many different diseases (17-18).The newly-characterized Interleukin-34 (IL-34) plays a central role in innate immunity and adaptive immunity, and is an important molecule for the communication between cells, tissues, and organs.Recently it has been reported that interleukin-34 (lL-34) stimulates monocyte viability but does not affect responses in a wide spectrum ofother assays (20)(21)(22)(23)(24)(25). In both in vitro and in vivo studies, IL-34 directly modulates the number and function of monocytes and regulates myeloid cell growth and differentiation. We believe that the immunological effects of IL-34 candidate this interleukin as an immunotherapeutic agent for the treatment of several different diseases (20,(26)(27)(28)(29)(30)(31)(32)(33)(34). To discover the receptor for IL-34, a collection ofextracellular domains oftrans-membrane proteins has been used which is a known cytokine receptor called colony-stimulating factor 1 receptor or macrophage colony-stimulating factor receptor

Allergic Inflammation: Role of Cytokines with Special Emphasis on IL-4

“…In some experimental animals, samples 24 h post-allergen challenge, there is an increased proportion of activated CD4+ T cells and in situ hybridization has revealed increased numbers ofcells expressing mRNA for IL-4, IL-5, and GM-CSF, but not IL-2, IL-3 or IFN-gamma (27). Consistent with this, the IL-4 and IL-5 mRNA are predominantly confined to T cells (28).…”

Cholesterol, Cytokines and Diseases

“…Interestingly, human lesions contain CD4+ T cells reactive to the diseaserelated antigens associated with oxidized LDL (32). The atherosclerotic lesion contains cytokines that promote a T-helper I response, inducing activated T cells to differentiate into T-helper 1 effector cells (33)(34)(35). These cells amplify the local inflammatory activity by producing proinflammatory cytokines such as IFN-and CD40 ligand (CD40L, CDI54), which contribute importantly to plaque progression.…”

Psychological Stress and Cancer

“…On the other hand, many studies have confirmed the influence of psychological factors on different aspects of the immune system, important in the process of tumor development (12). Cellular-mediated and humoral-mediated responses are affected in general psychiatry traumatic disorders, as is the production of cytokines (13)(14)(15). The hypothalamic-pituitaryadrenal axis responds to several compounds, such as inflammatory cytokines: tumor necrosis factor (TNF)-u, interleukin-I (lL-I) alpha and beta, interleukin-18, interleukin-33 and interleukin-6 (16)(17)(18)(19)(20)(21)(22).…”