Nisar Ahmed Khan

Chorionic gonadotropin induces dendritic cells to express a tolerogenic phenotype

The pregnancy hormone human chorionic gonadotropin (hCG) has been suggested to play an immunoregulatory role in addition to its endocrine function, thus contributing to the prevention of fetal rejection. We hypothesized that hCG is involved in the maternal‐fetal immune tolerance by the regulation of dendritic cell (DC) function. Therefore, we studied the effect of hCG on DC maturation. Upon hCG treatment in combination with LPS, mouse bone marrow‐derived DC (BMDC) increased the ratio of IL‐10:IL‐12p70, down‐regulated TNF‐α, and decreased antigen‐specific T cell proliferation. Addition of hCG together with LPS and IFN‐γ blocked MHC class II up‐regulation, increased IL‐10 production, and decreased the antigen‐specific T cell proliferation by DC. Splenic DC showed similar results. Upon hCG treatment, IDO mRNA expression and its metabolite kynurenine were increased by LPS‐ and IFN‐γ‐stimulated DC, suggesting its involvement in the decreased T cell proliferation. To study the effect of hCG on DC differentiation from precursors, BMDC were generated in the continuous presence of hCG. Under this condition, hCG decreased cytokine production and the induction of T cell proliferation. These data are suggestive for a contribution of hCG to the maternal‐fetal tolerance during pregnancy by modifying DC toward a tolerogenic phenotype.

Inhibition of diabetes in NOD mice by human pregnancy factor

Clinical symptoms of Th1 mediated autoimmune diseases regress in many patients during pregnancy. A prominent feature of pregnancy is the presence of human chorionic gonadotrophin hormone (hCG) in blood and urine. In this report we tested the effect of clinical grade hCG (c-hCG) on the development of diabetes, a Th1 mediated autoimmune disease, in nonobese diabetic (NOD) mice. We show that treatment of NOD mice with c-hCG before the onset of clinical symptoms lowered the increased blood glucose levels, reversed the established inflammatory infiltrate of pancreatic tissue, and profoundly inhibited the development of diabetes for prolonged time. c-hCG also induced profound inhibition of the functional activity (i.e. production of IFN-gamma) of Th1 cells. Transfer of spleen cells from c-hCG-treated NOD mice into immunocompromised NOD.SCID mice inhibited the development of diabetes in these otherwise nontreated mice. This shows that the treatment of the donor NOD mice induced persistent changes in the immune system. The antidiabetic activity of c-hCG was not caused by heterodimeric hCG or its subunits. Instead, this antidiabetic activity resided in a fraction of c-hCG preparation that contains a 400-2000 Dalton natural (immuno) modulatory pregnancy factor (NMPF).

Inhibition of septic shock in mice by an oligopeptide from the β-chain of human chorionic gonadotrophin hormone

Human chorionic gonadotrophin (hCG) is a heterodimeric placental glycoprotein hormone required in pregnancy. In human pregnancy urine and in commercial hCG preparations (c-hCG) it occurs in a variety of forms, including breakdown products. Several reports have suggested modulation of the immune system by intact hormone, but such effects of breakdown products have not been reported. In a related article (Hum Immunol 62:1315, 2001), it is reported that a 400-2000 Dalton (Da) fraction from c-hCG and from human pregnancy urine inhibits Th1-mediated diabetes in NOD mice. The active component(s) were called natural (immuno)modulatory pregnancy factor(s) (NMPF). This study reports that a single treatment with the same low molecular weight NMPF fraction up to 24-h after high dose lipopolysaccharide (LPS) injection inhibited septic shock in mice. This counteracting effect of NMPF paralleled the downregulation of the effects of LPS on the production of macrophage migration inhibitory factor (MIF) by spleen cells, on the plasma level of liver aminotransferase, and on the expression of several splenic lymphocyte and macrophage surface markers. Based on the primary structure of the beta-chain of hCG a synthetic hexapeptide Valine-Leucin-Proline-Alanine-Leucine-Proline (VLPALP) was designed, which demonstrated it to have the same protective effects as the 400-2000 Da NMPF fraction. These results indicate a new strategy for the treatment of septic shock and the potential of therapeutic use of this synthetic oligopeptide.

Chorionic gonadotropin can enhance innate immunity by stimulating macrophage function

Human chorionic gonadotropin (hCG) is a placental glycoprotein, mainly secreted by trophoblasts during pregnancy. Its function in endocrine regulation has been well documented, but its immunological role is still largely unclear. For a successful pregnancy, an effective innate immunity is needed to protect the mother and fetus against infection, while maintaining tolerance against the paternal antigens of the fetus. The aim of this study was to investigate the effect of hCG on the function of macrophages (Mϕ), which are major players in the innate response. hCG treatment of IFN‐γ‐primed Mϕ resulted in increased production of NO, reactive oxygen species, IL‐6 and IL‐12p40, and enhanced phagocytosis of apoptotic cells. hCG treatment did not affect the induction of allogeneic T cell proliferation by IFN‐γ‐primed Mϕ. The observed effects were receptor‐mediated and involved the protein kinase A signaling pathway, as indicated by blocking studies using specific inhibitors. In vivo thioglycollate‐elicited Mϕ also exhibited increased phagocytic ability upon IFN‐γ activation and hCG treatment. In conclusion, hCG enhances Mϕ functions involved in innate immunity, while the capacity to stimulate allogeneic T cells remains unchanged.

Synthetic oligopeptides related to the β-subunit of human chorionic gonadotropin attenuate inflammation and liver damage after (Trauma) hemorrhagic shock and resuscitation

Severe hemorrhagic shock (HS) followed by resuscitation induces a massive inflammatory response, which may culminate into systemic inflammatory response syndrome, multiple organ dysfunction syndrome, and, finally, death. Treatments that effectively prevent this inflammation are limited so far. In a previous study, we demonstrated that synthetic oligopeptides related to the primary structure of human chorionic gonadotropin (HCG) can inhibit the inflammatory response and mortality that follow high-dose LPS-induced inflammation. Considering this powerful anti-inflammatory effect, we investigated whether administration of similar synthetic HCG-related oligopeptides (LQGV, AQGV, LAGV) during HS were able to attenuate the inflammatory response associated with this condition. Hemorrhagic shock was induced in rats for 60 min by blood withdrawal until a MAP of 40 mmHg was reached. Rats received a single injection with one of the hCG-related oligopeptides (LQGV, AQGV or LAGV) or 0.9% NaCl solution as control 30 min after induction of HS. Treatment with LQGV, AQGV, or LAGV prevented systemic release of TNF-&agr; and IL-6 and was associated with reduced TNF-&agr;, IL-6, and E-selectin mRNA transcript levels in the liver. LQGV treatment prevented neutrophil infiltration into the liver and was associated with reduced liver damage. Our data suggest that HCG-related oligopeptides, in particular LQGV, have therapeutic potential by attenuating the life-threatening inflammation and organ damage that is associated with (trauma) HS and resuscitation.

Amelioration of renal ischaemia-reperfusion injury by synthetic oligopeptides related to human chorionic gonadotropin

BACKGROUND We have previously reported that small synthetic oligopeptides related to human beta-chorionic gonadotropin (beta-hCG) can reduce inflammation. Here we investigated whether such oligopeptides can reduce renal ischaemia-reperfusion injury in the mouse. METHODS Ten different oligopeptides were administered 1 min before induction of renal ischaemia and 1 min before reperfusion. RESULTS Survival at 72 h post-reperfusion was significantly higher in mice treated with oligopeptides MTRV, LQG, VLPALPQ or AQGV as compared to placebo-treated mice. Some oligopeptides were more effective than others. AQGV completely prevented mortality and best preserved kidney function. Next, AQGV was tested in a dose-escalating study in a range of 0.3-30 mg/kg. A survival gain was observed with all doses. Improvement of kidney function was observed from 1 mg/kg. Highest survival and best preserved kidney function were observed at 3 and 10 mg/kg. Upon treatment with AQGV, a significantly lower influx of neutrophils was found, apoptosis was decreased, whereas tubular epithelial cell proliferation was significantly increased at 24 h post-reperfusion. Serum levels of TNF-alpha, INF-gamma, IL-6 and IL-10 were significantly decreased at 24 h post-reperfusion. E-selectin mRNA levels in kidneys were significantly decreased at 6 h post-reperfusion. AQGV did not reduce mortality when treatment was started after reperfusion. CONCLUSIONS This study shows that small oligopeptides related to the primary structure of beta-hCG, especially AQGV, are promising potential drugs for preventing the development of renal ischaemia-reperfusion injury.

Synthetic human chorionic gonadotropin-related oligopeptides impair early innate immune responses to listeria monocytogenes in mice

Background. Synthetic human chorionic gonadotropin (hCG)-related oligopeptides are potent inhibitors of pathogenic inflammatory responses induced by in vivo lipopolysaccharide exposure or hemorrhagic shock-induced injury. In this study, we tested whether hCG-related oligopeptide treatment similarly altered inflammatory responses and innate host defenses in mice during experimental Listeria monocytogenes infection. Methods. Mice were infected with L. monocytogenes and treated with hCG-related oligopeptides (LQGV, VLPALP, or AQGV) or phosphate-buffered saline. Subsequently, mice were analyzed for bacterial loads, cytokine and chemokine responses, and inflammatory cell infiltrates in target organs. Results. Oligopeptide administration increased bacterial numbers in the spleen and liver at 6 h after infection. Simultaneously, CXCL1/KC and CCL2/MCP-1 plasma levels as well as neutrophil numbers in the spleen, blood, and peritoneal cavity decreased. In contrast, at 18 h after infection, systemic tumor necrosis factor alpha, interleukin 12 p70, interleukin 6, and interferon gamma levels increased statistically significantly in oligopeptide-treated mice compared with controls, which correlated with increased bacterial numbers. Conclusion. These data show that treatment with hCG-related oligopeptides (LQGV, VLPALP, and AQGV) inhibits early innate immune activation by reducing initial chemokine secretion following infection. This leads to bacterial overgrowth with subsequent enhanced systemic inflammation. Our data underscore the importance of early innate immune activation and suggest a role for hCG-derived oligopeptides at the placenta that increases the risk of L. monocytogenes infections.

Chorionic gonadotropin alleviates thioglycollate-induced peritonitis by affecting macrophage function

Human chorionic gonadotrophin (hCG) is a hormone produced during pregnancy and present at the implantation site and in the maternal blood. Pregnancy has been proposed to represent a controlled state of inflammation at an early stage at the implantation site and later, systemically extended to the maternal circulation. Earlier, we reported that hCG can inhibit the development of diabetes in NOD mice and LPS‐induced septic shock in a murine model. We hypothesize that hCG can contribute to the reduction of inflammation by modifying Mϕ function. Here, the TG‐induced peritonitis model for inflammation was used to investigate the effect of hCG on cytokine production and cell recruitment in vivo. hCG pretreatment in TG‐induced peritonitis increased the number of peritoneal cells, especially PMN and monocytes, compared with mice injected with TG only. This increased cell number was partially explained by increased cell survival induced by hCG. Despite the cellular infiltrate, hCG pretreatment decreased i.p. TNF‐α, IL‐6, PTX3, CCL3, and CCL5 levels. By depleting peritoneal resident Mϕ using clodronate liposomes prior to the application of hCG and the TG trigger, we established that Mϕ are the main responsive cells to hCG, as the suppressed TNF‐α and IL‐6 production and increased PMN influx are abolished in their absence. Together, these data suggest that hCG contributes to the controlled inflammatory state of pregnancy by regulating Mϕ proinflammatory function.

The β-human chorionic gonadotropin-related peptide LQGV reduces mortality and inflammation in a murine polymicrobial sepsis model.

Objective:Mortality in sepsis remains high and efforts to modulate the inflammatory response so far mostly failed to improve survival. The human chorionic gonadotropin-related tetrapeptide LQGV was recently shown to exert anti-inflammatory activity. The aim of this study was to assess the effect of LQGV on cecal ligation and puncture-induced mortality and inflammation. Design:Animal study. Setting:University research laboratory. Subjects:Male C57BL/6 mice. Interventions:To examine the effect of LQGV by itself on cecal ligation and puncture-induced mortality and inflammation, C57BL/6 mice were exposed to a moderate cecal ligation and puncture procedure (40% ligation and double puncture) with a mortality rate of approximately 80% within 5 days in control mice. In addition, to examine whether LQGV was of additive value to standard sepsis care (antibiotics and fluid resuscitation), a more severe cecal ligation and puncture procedure was used (80% ligation and double puncture), yielding approximately 100% mortality within 12 days in control mice. LQGV (5 mg/kg body weight), phosphate-buffered saline (as control), or dexamethasone (2.5 mg/kg body weight) was administered perioperatively. Survival was monitored for 21 days and inflammatory markers were determined in plasma, peritoneal cavity, and lungs. Measurements and Main Results:LQGV significantly improved survival from 20% to 50% during the first 5 days after moderate cecal ligation and puncture. This was associated with reduced cytokine and E-selectin levels in peritoneal lavage fluid, lungs, and, to a lesser extent, in plasma. LQGV treatment also reduced pulmonary nuclear factor-&kgr;B activation and pulmonary damage. In the severe cecal ligation and puncture model, LQGV combined with fluid resuscitation and antibiotics resulted in significantly better survival (70%) than that observed with fluid resuscitation and antibiotics alone (30%). Conclusions:LQGV improves survival after cecal ligation and puncture. This is likely established by a modest reduction of the acute inflammatory response through a nuclear factor-&kgr;B-dependent mechanism. Furthermore, LQGV may be a valuable additive next to the standard care in polymicrobial sepsis.

Chorionic gonadotropin up‐regulates long pentraxin 3 expression in myeloid cells

Pentraxin 3 (PTX3) is an acute‐phase response protein that initiates innate immunity against diverse microorganisms. It is produced in response to proinflammatory stimuli by many cell types including myeloid cells. Increased serum levels of PTX3 are found in pregnancy, a condition characterized by increased serum levels of the pregnancy hormone human chorionic gonadotropin (hCG). As myeloid cells bear the receptor for hCG, we hypothesized that hCG can promote innate immunity by affecting the PTX3 production by myeloid cells. In this paper, we demonstrate that hCG increases PTX3 expression by human monocytes, mouse dendritic cells, and mouse macrophages in vitro. This increased PTX3 expression by hCG is mediated via the protein kinase A signaling pathway. hCG injection in mice also increases the PTX3 serum levels. This serum PTX3 is produced mainly by blood monocytes, which from pregnant women, express more PTX3 compared with nonpregnant controls. The hCG‐induced hormones progesterone and estrogen also increase the PTX3 production by human monocytes. In conclusion, hCG increases innate immunity via induction of PTX3 in myeloid cells.