The effect of prolactin on immune cell subsets involved in SLE pathogenesis

Exploring the Immunomodulatory Potential of Pancreatic Cancer-Derived Extracellular Vesicles through Proteomic and Functional Analyses

Pancreatic cancer (PC) has a poor prognosis and displays resistance to immunotherapy. A better understanding of tumor-derived extracellular vesicle (EV) effects on immune responses might contribute to improved immunotherapy. EVs derived from Capan-2 and BxPC-3 PC cells isolated by ultracentrifugation were characterized by atomic force microscopy, Western blot (WB), nanoparticle tracking analysis, and label-free proteomics. Fresh PBMCs from healthy donors were treated with PC- or control-derived heterologous EVs, followed by flow cytometry analysis of CD8+ and CD4+ lymphocytes. The proteomics of lymphocytes sorted from EV-treated or untreated PBMCs was performed, and the IFN-γ concentration was measured by ELISA. Notably, most of the proteins identified in Capan-2 and BxPC-3 EVs by the proteomic analysis were connected in a single functional network (p = 1 × 10-16) and were involved in the "Immune System" (FDR: 1.10 × 10-24 and 3.69 × 10-19, respectively). Interestingly, the treatment of healthy donor-derived PBMCs with Capan-2 EVs but not with BxPC-3 EVs or heterologous control EVs induced early activation of CD8+ and CD4+ lymphocytes. The proteomics of lymphocytes sorted from EV-treated PBMCs was consistent with their activation by Capan-2 EVs, indicating IFN-γ among the major upstream regulators, as confirmed by ELISA. The proteomic and functional analyses indicate that PC-EVs have pleiotropic effects, and some may activate early immune responses, which might be relevant for the development of highly needed immunotherapeutic strategies in this immune-cold tumor.

Dysregulated Tfr/Tfh2 cells in patients with polycystic ovarian syndrome

Recent research revealed the pathogenic role of B cells in the pathogenesis of polycystic ovary syndrome (PCOS), while the Tfh cell plays a critical role in the B cell mediated autoantibody production and humoral immunity, but had not been investigated in PCOS patients. The frequency of Tfh and B cell subsets (Tfh1, Tfh2, Tfh17, naïve B, memory B, and plasma cells) in the peripheral blood of 21 PCOS patients and 15 healthy controls were investigated by flow cytometry. And the levels of follicle-stimulating hormone, luteinizing hormone, testosterone, prolactin and estradiol progesterone were measured by using the immunoluminescence method. Also, the associations between these hormone levels and Tfh cell subsets or B cell subsets were analyzed. No significant difference was observed in total Tfh cells between 21 PCOS patients and 15 healthy controls (p > 0.05). But the percentages of Tfh2 and plasma cells were significantly higher in 21 PCOS patients compared to 15 healthy controls (p < 0.05). In contrast, the frequency of Tfr cells and Tfr/Tfh2 ratio were significantly lower than healthy controls (p < 0.01). Importantly, among these cells, only the percentage of Tfh2 cells was positively correlated with the levels of testosterone (r = 0.513, p = 0.018). And the percentage of Tfr cells and Tfr/Tfh2 ratio were also positively correlated with the levels of testosterone (r = 0.567, p = 0.007; r = 0.434, p = 0.05) and prolactin (r = 0.511, p = 0.018; r = 0.490, p = 0.024). These new findings provide unique insights into dysregulated Tfh/Tfr cells in mediating the immunopathogenesis of PCOS patients.

The significance of prolactin in systemic connective tissue diseases

Objectives

Does prolactin (PRL) level testing in the diagnosis of systemic connective tissue diseases make sense and should we test it in everyday practice?

Material and methods

Connective tissue diseases (CTDs) are a group of heterogeneous disorders, involving multiple body systems. Rheumatoid arthritis (RA) is one of the most common connective tissue diseases with a global prevalence of 0.3-1% and can be inherited. Less common are systemic lupus erythematosus (SLE), antiphospholipid syndrome (APS), systemic sclerosis (SSc), primary Sjögren's syndrome (pSS) and inflammatory myositis. Prolactin is responsible for lactation, breast growth and many other bodily processes, and is elevated in blood of woman who are pregnant or breastfeeding. Hyperprolactinemia is relatively common in women, so some rheumatic diseases may be caused by high prolactin levels, and it should be detected during diagnosis.

Results

Prolactin signals are found in arthritic joint tissues (chondrocytes and synovial fibroblasts) to inhibit cartilage degradation, synovitis and osteoclastogenesis. On the other hand, hyperprolactinemia also promotes the conversion of PRL to vasoinhibin, a fragment of PRL that directly stimulates and indirectly inhibits arthritis in a cell type-dependent manner. The role of the PRL/vasoinhibin axis in inflammatory arthritis should still be monitored and further research is needed to help elucidate the role of PRL in rheumatic diseases in order to ultimately develop new therapeutic interventions that can be tested in patients.

Conclusions

Nowadays, there are no clear indications for prolactin testing in the diagnosis of systemic connective tissue diseases. In the case of suspicion or confirmation of some systemic connective tissue diseases, such as rheumatoid arthritis or systemic lupus erythematosus, testing the prolactin level makes sense when severity of disease symptoms is observed.

Immunomodulatory role of decidual prolactin on the human fetal membranes and placenta

The close interaction between fetal and maternal cells during pregnancy requires multiple immune-endocrine mechanisms to provide the fetus with a tolerogenic environment and protection against any infectious challenge. The fetal membranes and placenta create a hyperprolactinemic milieu in which prolactin (PRL) synthesized by the maternal decidua is transported through the amnion-chorion and accumulated into the amniotic cavity, where the fetus is bedded in high concentrations during pregnancy. PRL is a pleiotropic immune-neuroendocrine hormone with multiple immunomodulatory functions mainly related to reproduction. However, the biological role of PRL at the maternal-fetal interface has yet to be fully elucidated. In this review, we have summarized the current information on the multiple effects of PRL, focusing on its immunological effects and biological significance for the immune privilege of the maternal-fetal interface.