Deletion of p21 (WAF-1/Cip1) Does Not Induce Systemic Autoimmunity in Female BXSB Mice

Systemic lupus erythematosus (SLE) is a progressive autoimmune disease characterized by the production of high levels of affinity-matured IgG autoantibodies to dsDNA and, possibly, visceral involvement. Pathogenic autoantibodies result from the activation and proliferation of autoreactive T and B lymphocytes stimulated by epitopes borne by nucleosomal histones. To inhibit the proliferation of autoreactive cells and abrogate the development of SLE, a novel tool, cell cycle inhibiting peptide therapy, was used. Thus, a peptidyl mimic of p21WAF1/CIP1 that inhibits the interaction between cyclin-dependent kinase 4 and type D cyclins abrogated the in vitro proliferative response of T cells to histones and T-independent and T-dependent proliferative responses of B cells. The WAF1/CIP1 mimic also abrogated the in vitro production of total and anti-dsDNA IgG Abs by B cells. Similarly, the p21WAF1/CIP1 construct inhibited the ex vivo T and B cell proliferative responses to histones and decreased the numbers of activated/memory B and T spleen cells. The alterations in the balance of spleen cell subsets resulted from proapoptotic effects of the p21WAF1/CIP1 construct on activated splenocytes. Finally, in vivo, four i.v. injections of the p21WAF1/CIP1 mimic were sufficient to inhibit the progression of the lupus-like syndrome in (NZB × NZW)F1 mice. The levels of anti-dsDNA IgG autoantibodies and the incidence and severity of renal involvement were lower in treated mice than in nontreated mice. Those observations open new avenues for the treatment of SLE and prompt us to evaluate the potential interest of peptidic therapy in human SLE.

Section: Discussionmentioning

confidence: 99%

A Mimic of p21WAF1/CIP1 Ameliorates Murine Lupus

Goulvestre

Chéreau

Nicco

et al. 2005

“…In addition to the above studies, BXSB p21 Ϫ/Ϫ mice were generated, and it was reported that p21 deficiency did not affect the mild autoimmunity that characterizes BXSB female mice (10). On the basis of this work, the authors concluded that deletion of p21 is unrelated to autoimmunity induction and claimed that previous data showing an autoimmune predisposition in p21 Ϫ/Ϫ mice could be confounded by the autoimmunity predisposition of mixed background mice (10).…”

mentioning

confidence: 88%

p21CIP1/WAF1 Controls Proliferation of Activated/Memory T Cells and Affects Homeostasis and Memory T Cell Responses

Arias

Ballesteros-Tato

García

et al. 2007

Development of autoantibodies and lupus-like autoimmunity by 129/Sv × C57BL/6 p21−/− mice has established that cell cycle deregulation is one the defective pathways leading to break of tolerance. Memory T cell accumulation is thought to be related to tolerance loss in murine lupus models. We studied T cell memory responses in C57BL/6 p21−/− mice that develop lupus-like disease manifestations. p21 did not affect primary proliferation of naive T cells, and was required for cycling control, but not for apoptosis of activated/memory T cells. When we induced apoptosis by secondary TCR challenge, surviving memory T cells depended on p21 for proliferation control. Under conditions of secondary T cell stimulation that did not cause apoptosis, p21 was also needed for regulation of activated/memory T cell expansion. The requirement for p21 in the control of T cell proliferation of activated/memory T cells suggests that in addition to apoptosis, cycling regulation by p21 constitutes a new pathway for T cell homeostasis. Concurring with this view, we found accumulation in p21−/− mice of memory CD4+ T cells that showed increased proliferative potential after TCR stimulation. Furthermore, OVA immunization of p21−/− mice generated hyperresponsive OVA-specific T cells. Overall, the data show that p21 controls the proliferation of only activated/memory T cells, and suggest that p21 forms part of the memory T cell homeostasis mechanism, contributing to maintenance of tolerance.

“…Abnormalities in some of these genes, such as C1q, DNase1, and Fas, have been identified in rare patients with SLE or lymphoproliferative disorders (20 -23). Murine studies have also emphasized the importance of background genes in determining the phenotypes resulting from single gene alterations (7,24,25). The (NZB ϫ NZW)F 1 mouse has been carefully analyzed genetically because it represents a polygenic model for SLE (1,26,27).…”

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confidence: 99%

Development of Autoimmunity in IL-14α-Transgenic Mice

Shen

Zhang

Wang

et al. 2006

110

Multiple genetic loci contribute to the development of systemic lupus erythematosus (SLE). In murine models for SLE, various genes on chromosome four have been implicated. IL-14 is a cytokine originally identified as a B cell growth factor. The il14 gene is located on chromosome 4. IL-14α is a cytokine encoded by the plus strand of the IL-14 gene using exons 3–10. The expression of IL-14α is increased in (NZB × NZW)F1 mice. In this study, we produced IL-14α-transgenic mice to study the role of IL-14α in the development of autoimmunity. At age 3–9 mo, IL-14α-transgenic mice demonstrate increased numbers of B1 cells in the peritoneum, increased serum IgM, IgG, and IgG 2a and show enhanced responses to T-dependent and T-independent Ags compared with littermate controls. At age 9–17 mo, IL-14α-transgenic mice develop autoantibodies, sialadenitis, as in Sjögren’s syndrome, and immune complex-mediated nephritis, as in World Health Organization class II SLE nephritis. Between the ages 14–18 mo, 95% of IL-14α-transgenic mice developed CD5+ B cell lymphomas, consistent with the lymphomas seen in elderly patients with Sjögren’s syndrome and SLE. These data support a role for IL-14α in the development of both autoimmunity and lymphomagenesis. These studies may provide a genetic link between these often related disorders.