Polne razlike u kliničkoj slici i terapiji multiple skleroze

Multiple sclerosis (MS) is more prevalent in women than in men, with the female to male ratio in the prevalence of MS constantly increasing. Besides, sex appears to affect the development, progression, clinical manifestation and therapy response in MS. These sex differences, most likely, emerge from the genetic, epigenetic and hormonal differences between the sexes, differences in environmental exposure and/or susceptibility to certain factors, as well as from the biological differences in the female and male immune and nervous system. Therefore, sex differences in all of these aspects need to be taken into consideration when designing and interpreting research findings related to MS, and particularly in development of new therapeutic strategies and designing of clinical drug trials. Understanding the mechanisms underlying sex differences in the pathogenesis and/or therapy response in MS could also narrow the gap in our knowledge of the pathogenesis/therapy of a broad spectrum of other autoimmune diseases that are characterized by sexual dimorphism in the prevalence and/or clinical presentation.Multipla skleroza (MS) se češće javlja kod žena nego kod muškaraca i disproporcija između obolevanja žena i muškaraca od ove bolesti pokazuje tendenciju stalnog rasta. Pol ima kritičnu ulogu u razvoju, progresiji, kliničkim manifestacijama MS i odgovoru na terapiju. Ove razlike su, najverovatnije, posledica delovanja genetskih, epigenetskih i hormonskih faktora, razlika u izloženosti pojedinim sredinskim faktorima, kao i bioloških razlika između imunskog i nervnog sistema žena i muškaraca. Polne razlike u svim ovim aspektima se moraju uzeti u obzir prilikom dizajniranja i tumačenja rezultata istraživanja vezanih za patogenezu MS, a posebno prilikom razvoja novih terapijskih strategija i kliničkih istraživanja lekova namenjenih lečenju ove bolesti. Razumevanje mehanizama koji stoje u osnovi polnih razlika u patogenezi i/ili odgovoru na terapiju u MS bi moglo biti relevantno i za širi spektar autoimunskih bolesti u kojima je izražen polni dimorfizam u incidenci i prevalenci i/ili kliničkim manifestacijama bolesti

Strain-specific differences in age-related changes in rat susceptibility to experimental autoimmune encephalomyelitis and dendritic cell cytokine gene expression

Experimental autoimmune encephalomyelitis (EAE) is an animal model of multiple sclerosis, a prototype of Th1/Th17-mediated organ-specific autoimmune disease. In the rat, susceptibility to development of these diseases is shown to be strain-and age-dependent. In adult rats of distinct strains, it correlates with splenic dendritic cell (DC) subset composition, which also exhibit age-related changes. The aim of this study was to examine influence of aging on: i) Albino Oxford (relatively resistant to EAE) and Dark Agouti (susceptible to EAE) rat development of EAE and ii) their splenic conventional (OX62+) DC population in respect to its subset composition and expression of mRNAs for proinflammatory and immunosuppressive cytokines. We used 3-month-old (young) and 26-month-old (aged) rats of AO and DA strain. The rats were immunized for EAE with rat spinal cord homogenate in complete Freund's adjuvant and clinical course of the disease was followed. Fresh OX62+DCs were examined for the expression of CD4 (using flow cytometry) and genes encoding cytokines influencing DC activation/maturation (TNF-alpha and IL-6) using RT-PCR. Additionally, in vitro lipopolysaccharide (LPS) activated/matured DCs were examined for the expression of genes encoding cytokines controlling Th1/Th17 cell polarization using RT-PCR. With aging, AO rats became more susceptible, whereas DA rats largely lose their susceptibility to the induction of EAE. In AO rats aging shifted CD4+: CD4-DC ratio towards CD4- cells, producing large amount of proinflammatory cytokines, whereas in DA rats CD4+: CD4-DC ratio remained stable with aging. In fresh DCs from rats of both the strains the expression of TNF-alpha mRNA increased with aging, whereas that of IL-6 mRNA decreased and increased in DCs from AO and DA rats, respectively. Following in vitro LPS stimulation OX62+ DCs from aged AO rats up-regulated the expression of mRNA for IL-23p19 (specific subunit of IL-23; crucial for sustained IL-17 production) and IL-1 beta (positive IL-17 regulator), whereas down-regulated the expression of IL-10 (negative IL-17 regulator) when compared with young strain-matched rats. In DA rats aging incresed IL-23p19 mRNA expression in LPS-stimulated DCs, whereas exerted the opposing effects on the expression of mRNAs for IL-10 and IL-1 beta compared to AO rats. Irrespective of the rat strain, aging did not influence mRNA expression for IL-12p35 (driving Th1 polarization) in DCs. Overall, results suggest role of changes in the expression of genes encoding proinflammatory and immunosuppressive cytokines in development of age-related alterations in rat susceptibility to EAE induction

Sex differences in Tfh cell help to B cells contribute to sexual dimorphism in severity of rat collagen-induced arthritis

The study examined germinal centre (GC) reaction in lymph nodes draining inflamed joints and adjacent tissues (dLNs) in male and female Dark Agouti rat collagen type II (CII)-induced arthritis (CIA) model of rheumatoid arthritis. Female rats exhibiting the greater susceptibility to CIA mounted stronger serum CII-specific IgG response than their male counterparts. This correlated with the higher frequency of GC B cells in female compared with male dLNs. Consistently, the frequency of activated/proliferating Ki-67+ cells among dLN B cells was higher in females than in males. This correlated with the shift in dLN T follicular regulatory (Tfr)/T follicular helper (Tfh) cell ratio towards Tfh cells in females, and greater densities of CD40L and CD40 on their dLN T and B cells, respectively. The higher Tfh cell frequency in females was consistent with the greater dLN expression of mRNA for IL-21/27, the key cytokines involved in Tfh cell generation and their help to B cells. Additionally, in CII-stimulated female rat dLN cell cultures IFN-gamma /IL-4 production ratio was shifted towards IFN-gamma. Consistently, the serum IgG2a(b)/IgG1 CII-specific antibody ratio was shifted towards an IgG2a(b) response in females. Thus, targeting T-/B-cell interactions should be considered in putative further sex-based translational pharmacology research

Strain differences in thymic atrophy in rats immunized for EAE correlate with the clinical outcome of immunization

An accumulating body of evidence suggests that development of autoimmune pathologies leads to thymic dysfunction and changes in peripheral T-cell compartment, which, in turn, perpetuate their pathogenesis. To test this hypothesis, thymocyte differentiation/maturation in rats susceptible (Dark Agouti, DA) and relatively resistant (Albino Oxford, AO) to experimental autoimmune encephalomyelitis (EAE) induction was examined. Irrespective of strain, immunization for EAE (i) increased the circulating levels of IL-6, a cytokine causally linked with thymic atrophy, and (ii) led to thymic atrophy reflecting partly enhanced thymocyte apoptosis associated with downregulated thymic IL-7 expression. Additionally, immunization diminished the expression of Thy-1, a negative regulator of TCR alpha beta-mediated signaling and activation thresholds, on CD4+CD8+ TCR alpha beta(lo/hi) thymocytes undergoing selection and thereby impaired thymocyte selection/survival. This diminished the generation of mature CD4+ and CD8+ single positive TCR alpha beta(hi) thymocytes and, consequently, CD4+ and CD8+ recent thymic emigrants. In immunized rats, thymic differentiation of natural regulatory CD4+Foxp3+CD25+ T cells (nTregs) was particularly affected reflecting a diminished expression of IL-7, IL-2 and IL-15. The decline in the overall thymic T-cell output and nTreg generation was more pronounced in DA than AO rats. Additionally, differently from immunized AO rats, in DA ones the frequency of CD28- cells secreting cytolytic enzymes within peripheral blood CD4+ T lymphocytes increased, as a consequence of thymic atrophy-related replicative stress (mirrored in CD4+ cell memory pool expansion and p16(INK4a) accumulation). The higher circulating level of TNF-alpha in DA compared with AO rats could also contribute to this difference. Consistently, higher frequency of cytolytic CD4+ granzyme B+ cells (associated with greater tissue damage) was found in spinal cord of immunized DA rats compared with their AO counterparts. In conclusion, the study indicated that strain differences in immunization-induced changes in thymopoiesis and peripheral CD4+CD28- T-cell generation could contribute to rat strain-specific clinical outcomes of immunization for EAE

Sexual dimorphism in the severity of rat collagen-induced arthritis: The relevance of T follicular cell help to B cells

Collagen-induced arthritis (CIA) is a well-established experimental model mimicking many immunopathogenic and clinical aspects of rheumatoid arthritis (RA), including sexual dimorphism in the clinical presentation. Our previous study showed that a more severe disease in female compared with male rats correlated with more robust Th17 response reflecting sexual dimorphism in Th17/Treg axis plasticity. Given that autoantibodies play a significant role in the immunopathogenesis of RA and CIA, in the present study the germinal center (GC) reaction in the lymph nodes draining inflamed joints and adjacent tissue (dLNs) was examined for putative sexual dimorphism. Female rats mounted greater serum collagen II-specific IgG response than their male counterparts. This dimorphism correlated with the higher frequency of GC B cells in female compared with male dLNs. Consistently, the frequency of activated/proliferating Ki67+ cells among dLN B cells was higher in females than in males. This was associated with the shift in dLN T follicular regulatory (Tfr)/T follicular helper (Tfh) cell ratio towards Tfh cells in females, and greater densities of CD40L and CD40 on their dLN T and B cells, respectively. The higher Tfh cell frequency in females was consistent with the greater dLN expression of mRNA for IL 21/27, the key cytokines involved in Tfh cell generation and help to B cells. Additionally, in collagen II-stimulated female rat dLN cell cultures, IFN-γ/IL-4 ratio was shifted towards IFN-γ. Consistently, serum ratio between pathogenic IgG2a and protective IgG1 collagen II-specific antibodies was shifted towards the former in females. Thus, the study suggests that targeting T/B cell interactions should be considered in further translation research aimed to design sex-specific therapies for RA

Hormoni ovarijuma imaju različit uticaj na modelovanje apoptoze i proliferacije unutar različitih subpopulacija timocita tokom involucije timusa

The study was aimed to define the putative role of ovarian hormones in shaping thymocyte apoptosis and proliferation during thymic involution. Thymocytes from young adult and middle-aged rats ovariectomized (Ox) before puberty were examined for apoptosis and proliferation. Apoptosis and proliferation were measured in fresh thymocyte suspensions and in their 18-hour cultures, and fresh thymocyte suspensions, respectively. The thymocyte population and the major thymocyte subsets were analyzed following triple staining using anti-CD4 and anti-CD8 monoclonal antibodies and 7-AAD to label apoptotic or proliferating cells. The frequency of apoptotic cells was lower in thymocyte suspensions and cultures from Ox rats of both ages. This reflected in a diminished frequency of apoptotic cells amongst CD4+CD8+ double positive (DP) and CD4+CD8- single positive (SP), and DP cells in young and middle-aged Ox rats, respectively. Additionally, in thymocyte cultures from Ox rats the frequency of apoptotic cells amongst CD4+CD8- and CD4-CD8+ SP cells decreased with age, but increased within DP and CD4-CD8- double negative (DN) subsets, reaching in the former subset from middle-aged Ox rats higher values than in age-matched controls. The frequency of proliferating cells was also lower in Ox rats than in controls. This reflected the lower frequency of cycling cells amongst CD4+CD8- SP and CD4-CD8+ SP thymocytes in young rats, and DP and CD4-CD8+ SP thymocytes in middle-aged rats. Besides, in both SP and DP thymocyte subsets from Ox rats the frequency of proliferating cells declined with age. In conclusion, thymocyte apoptosis and proliferation exhibit ovarian hormone-dependent thymocyte subset specific alterations during thymic involution.Cilj istraživanja je bio da se definiše značaj hormona ovarijuma za razvoj promena u apoptozi i proliferaciji timocita tokom involucije timusa. U tom cilju apoptoza i proliferacija timocita ispitivana je kod prepubertetno ovariektomisanih (Ox) mladih (uzrasta 2 meseca) i sredovečnih pacova (uzrasta 11 meseci). Apoptoza je određivana u suspenziji sveže izolovanih timocita i nakon njihove 18- časovne kultivacije, a proliferacija u suspenziji sveže izolovanih timocita. Procenat apoptotičnih i proliferišućih ćelija je određivan u celokupnoj populaciji timocita, i unutar glavnih subpopulacija ovih ćelija, koje su razdvojene na osnovu ekspresije CD4/CD8 molekula, metodom protočne fluorocitometrije, korišćenjem 7-aminoaktinomicina D (7-AAD). Procenat ćelija u apoptozi je bio značajno manji u suspenzijama svežih timocita koji su izolovani iz Ox životinja i u njihovim kulturama nego u onim izolovanim iz kontrolnih životinja. Ovaj nalaz je odražavao smanjenu učestalost ćelija u apoptozi u CD4+CD8+ dvostruko pozitivnoj (DP) i CD4+CD8- jednostruko pozitivnoj (JP) subpopulaciji timocita kod mladih i u DP subpopulaciji kod sredovečnih Ox pacova. U kulturama timocita koji su izolovani iz sredovečnih Ox pacova uočeno je smanjenje učestalosti ćelija u apoptozi unutar subpopulacija CD4+CD8- i CD4-CD8+ JP timocita, a povećanje unutar DP i CD4-CD8- dvostruko negativne (DN) subpopulacije ovih ćelija. Učestalost proliferišućih ćelija je takođe bila niža u suspenzijama timocita izolovanih iz Ox pacova nego u onim izolovanim iz kontrolnih životinja. Ovo je odražavalo smanjenu proliferaciju CD4+CD8- i CD4-CD8+ JP timocita kod mladih, a DP i CD4-CD8+ JP timocita kod sredovečnih pacova. Procentualna zastupljenost proliferišućih ćelija u subpopulacijama JP i DP timocita je bila veća kod mladih nego kod sredovečnih Ox pacova. U zaključku, tokom involucije timusa dolazi do promena u apoptozi i proliferaciji timocita koje su specifične za pojedine subpopulacije timocita i zavisne od prisustva hormona ovarijuma

Ovarian hormone level alterations during rat post-reproductive life-span influence CD8+T-cell homeostasis

The study examined the putative role of ovarian hormones in shaping of rat peripheral T-cell compartment during post-reproductive period. In 20-month-old rats ovariectomized (Ox) at the very end of reproductive period, thymic output, cellularity and composition of major TCR alpha beta+peripheral blood lymphocyte and splenocyte subsets were analyzed. Ovariectomy led to the enlargement of CD8 + peripheral blood lymphocyte and splenocyte subpopulations. This reflected: (i) a more efficient thymic generation of CD8 + cells as indicated by increased number of CD4+CD8+double positive and the most mature CD4CD8+TCR alpha beta(high) thymocytes and CD8 + recent thymic emigrants (RTEs) in peripheral blood, but not in the spleen of Ox rats, and (ii) the expansion of CD8 + memory/activated peripheral blood lymphocytes and splenocytes. The latter was consistent with a greater frequency of proliferating cells among freshly isolated memory/activated CD8 + peripheral blood lymphocytes and splenocytes and increased proliferative response of CD8 + splenocytes to stimulation with plate-bound anti-CD3 antibody. The former could be related to the rise in splenic IL-7 and IL-15 mRNA expression. Although ovariectomy affected the overall number of CD4 + T cells in none of the examined compartments, it increased CD4+FoxP3 + peripheral blood lymphocyte and splenocyte counts by enhancing their generation in periphery. Collectively, the results suggest that ovariectomy-induced long-lasting disturbances in ovarian hormone levels (mirrored in diminished progesterone serum level in 20-month-old rats) affects both thymic CD8 + cell generation and peripheral homeostasis and leads to the expansion of CD4+FoxP3 + cells in the periphery, thereby enhancing autoreactive cell control on account of immune system efficacy to combat infections and tumors

Aging impairs endocytic capacity of splenic dendritic cells from Dark Agouti rats and alters their response to TLR4 stimulation

The study was undertaken considering: i) that relative proportion of distinct subsets of splenic dendritic cells (DCs) is strain-specific and predictive for the susceptibility to autoimmune diseases; ii) age-related changes in endocytic, allostimulatory and polarizing capacity of splenic OX62+ DCs from Albino Oxford rats (relatively resistant to Th1/Th17-mediated diseases) and iii) strain specificities in age-related changes of mouse DCs. To ascertain whether there are strain specificities in age-related rat DC changes, we examined the influence of aging on OX62+ DCs from Dark Agouti (DA) rats prone to Th1/Th17-mediated autoimmune diseases. The study provided additional evidence that the predominance of CD4-cells within OX62+ DCs from young adult rats correlates with their susceptibility to Th1/Th17-mediated diseases. Consistently, lipopolysaccharide (LPS)-matured DCs from 3-month-old (young) rats exhibited Th1 driving force when co-cultured with allogeneic CD4+ T cells. This most likely reflected enhanced TNF-alpha and iNOS expression. Comparing with young rats, OX62+ DCs from 26-month-old (aged) rats showed: i) diminished endocytic capacity; ii) impaired ability to mature in vitro upon LPS stimulation (as indicated by lower MHC II, CD86 and CD40 surface expression), which is consistent with the increase in their IL-10 production, and iii) diminished allostimulatory capacity and loss of Th1-driving capacity in the mixed lymphocyte reaction. The latter, probably, reflected greater IL-10 production by LPS-stimulated DC from aged rats, as well as lower CD40 density on their surface. Overall, our findings suggest that aging might affect DA rat capability to mount an efficient Th1 immune response, and consequently susceptibility to Th1/Th17-mediated pathology

Oleuropein Attenuates Oxidative Stress in Human Trophoblast Cells

Olive-derived bioactive compound oleuropein was evaluated against damage induced by hydrogen peroxide in human trophoblast cells in vitro, by examining the changes in several markers implicated in oxidative stress interactions in the placenta. Trophoblast HTR-8/SVneo cells were preincubated with OLE at 10 and 100 µM and exposed to H2O2, as a model of oxidative stress. Protein and lipid peroxidation, as well as antioxidant enzymes’ activity, were determined spectrophotometrically, and DNA damage was evaluated by comet assay. iNOS protein expression was assessed by Western blot, while the mRNA expression of pro- and anti-apoptotic genes BAX and BCL2 and transcription factor NFE2L2, as well as cytokines IL-6 and TNF α were determined by qPCR. Oleuropein demonstrated cytoprotective effects against H2O2 in trophoblast cells by significantly improving the antioxidant status and preventing protein and lipid damage, as well as reducing the iNOS levels. OLE reduced the mRNA expression of IL-6 and TNF α, however, it did not influence the expression of NFE2L2 or the BAX/BCL2 ratio after H2O2 exposure. Oleuropein per se did not lead to any adverse effects in HTR-8/SVneo cells under the described conditions, confirming its safety in vitro. In conclusion, it significantly attenuated oxidative damage and restored antioxidant functioning, confirming its protective role in trophoblast. © 2023 by the authors