Comparative Study of Senescent Th Biomarkers in Healthy Donors and Early Arthritis Patients. Analysis of VPAC Receptors and Their Influence

Abstract

Pro-inflammatory CD4+CD28− T cells are characteristic of immunosenescence, but also of several autoimmune/inflammatory diseases. Vasoactive intestinal peptide (VIP) acts as an anti-inflammatory and immunomodulatory mediator on these cells. Our objective was to study the mutual influence between senescent Th cells and VIP axis in early arthritis (EA), comparing with non-EA donors. We characterized the correlation between senescent Th cells and clinic parameters of EA as well as the behavior of senescent Th biomarkers by real-time PCR. Clinical data were systematically recorded at baseline and after 6 months of follow-up. The number of CD4+CD28− T cells measured by sorting is higher in patients who initially meet ACR classification criteria for rheumatoid arthritis (RA) compared to those who were classified as undifferentiated arthritis (UA). A slight positive correlation between EA CD4+CD28− T cells and CRP or ESR and a negative correlation with bone mineral density were found. Th senescent biomarkers in EA CD4+CD28− T cells were similar to donors, however some of them increased after 6 months of follow-up. VPAC receptors were analyzed by real-time PCR and immunofluorescence, and CD4+CD28− T cells showed higher expression of VPAC2 and lower of VPAC1, VPAC2 showing a significant increased expression in EA cells. Sorted CD4+CD28− T cells were in vitro expanded in presence of VIP, wherein VIP increased senescent biomarker CD27, while it diminished CD57 or NKG2 senescent biomarkers. Our study demonstrates for the first time the existence of a link between senescent Th cells and the VIP axis.

Human CD4+CD45RA+ T Cells Behavior after In Vitro Activation: Modulatory Role of Vasoactive Intestinal Peptide

“…In the puzzle of the data describing the role of VIP and its receptors in the immune system [17][18][19]50], a key piece is missing: understanding how the presence of VIP affects the activation/differentiation of human naїve T cells without any preconditioning culture medium, and how its receptors are modulated during this process. To fill this gap, we first analyzed the expression of VPAC receptors, observing a significant increase in VPAC 2 mRNA and protein expression after 4 days of activation similar to that observed in other lymphocyte states as the activated CD4 + CD45RO + , senescent lymphocytes or Th17-differentiated cells [17,18,22,51,52]. There is a difference in the timing of memory Th cells activation, as the increase in VPAC 2 receptor expression was observed from day 1 in this last population [52].…”

“…VIP actions can be affected not only by changes in VPAC expression in lymphocytes but also changes in cellular location as occurs with other GPCRs or even VPAC 1 in other types of cells [54][55][56][57]. In resting human memory (CD4 + CD45RO + ) or senescent Th lymphocytes (CD4 + CD28 − ), VPAC 1 is located on the plasma membrane and nucleus whereas it only appears in the nucleus in activated memory Th cells [22,52]. Present results with CD4 + CD45RA + T cells show similar cellular location in resting and activation states, where both VPAC 1 and VPAC 2 receptors are always found in the plasma membrane location independently of activation state as occurs with memory Th cells [52].…”

“…This neuropeptide exerts its actions through two specific receptors named VPAC 1 and VPAC 2 that belong to the B1 family of G-protein coupled receptors (GPCRs). In different non-immune and immune cells, including fibroblast synoviocytes, in vitro differentiated osteoclast, macrophages and lymphocytes, the pattern expression of these receptors changes with the degree of cellular activation, maturation or differentiation [17,[20][21][22]. In the specific case of human and mouse CD4 + T lymphocytes, it was described that their activation induces a loss in mRNA expression of VPAC 1 , whereas an important increase in VPAC 2 appears [17,[23][24][25].…”

VIP/VPAC Axis Expression in Immune-Mediated Inflammatory Disorders: Associated miRNA Signatures

“…The higher expression of VPAC2 receptor could be interpreted as a reinforcement and compensation mechanism when there is loss of VPAC1 receptor function under pathological conditions. In this sense, VPAC2 has also been shown to be the predominant receptor in PBMC in early arthritis in different experimental conditions, such as activated memory Th cells, Th17-polarized cells, and proinflammatory CD4+CD28− T cells [ 31 , 32 , 33 ]. Moreover, this increased expression has been described in monocytes from Sjögren syndrome [ 34 ] and CD4 T cells from multiple sclerosis [ 35 ].…”

Molecular and Cellular Basis of Autoimmune Diseases

“…In this special issue, Villanueva-Romero et al analyze the senescent Th biomarkers in healthy donors and early arthritis patients and examine the bidirectional influence between the VIP axis and senescent Th cells. These pro-inflammatory cells are characteristic of immunosenescence but also several autoimmune/inflammatory diseases [ 18 ]. The paper describes that patients who meet classification criteria for RA have a higher percentage of CD4 + CD28 − than those with undifferentiated arthritis.…”