The LPS induced pyroptosis exacerbates BMPR2 signaling deficiency to potentiate SLE-PAH.

Pulmonary arterial hypertension (PAH) is a common and fatal complication of systemic lupus erythematosus (SLE). Whether the BMP receptor deficiency found in the genetic form of PAH is also involved in SLE-PAH patients remains to be identified. In this study, we employed patient-derived samples from SLE-associated PAH (SLE-PAH) and established comparable mouse models to clarify the role of BMP signaling in the pathobiology of SLE-PAH. Firstly, serum levels of LPS and autoantibodies (auto-Abs) directed at BMP receptors were significantly increased in patients with SLE-PAH compared with control subjects, measured by ELISA. Mass cytometry was applied to compare peripheral blood leukocyte phenotype in patients prior to and after treatment with steroids, which demonstrated inflammatory cells alteration in SLE-PAH. Furthermore, BMPR2 signaling and pyroptotic factors were examined in human pulmonary arterial endothelial cells (PAECs) in response to LPS stimulation. Interleukin-8 (IL-8) and E-selectin (SELE) expressions were up-regulated in autologous BMPR2+/R899X endothelial cells and siBMPR2-interfered PAECs. A SLE-PH model was established in mice induced with pristane and hypoxia. Moreover, the combination of endothelial specific BMPR2 knockout in SLE mice exacerbated pulmonary hypertension. Pyroptotic factors including gasdermin D (GSDMD) were elevated in the lungs of SLE-PH mice, and the pyroptotic effects of serum samples isolated from SLE-PAH patients on PAECs were analyzed. BMPR2 signaling upregulator (BUR1) showed anti-pyroptotic effects in SLE-PH mice and PAECs. Our results implied that deficiencies of BMPR2 signaling and proinflammatory factors together contribute to the development of PAH in SLE.

Anti-Müllerian hormone concentration regulates activin receptor-like kinase-2/3 expression levels with opposing effects on ovarian cancer cell survival.

Anti­Müllerian hormone (AMH) type II receptor (AMHRII) and the AMH/AMHRII signaling pathway are potential therapeutic targets in ovarian carcinoma. Conversely, the role of the three AMH type I receptors (AMHRIs), namely activin receptor­like kinase (ALK)2, ALK3 and ALK6, in ovarian cancer remains to be clarified. To determine the respective roles of these three AMHRIs, the present study used four ovarian cancer cell lines (COV434­AMHRII, SKOV3­AMHRII, OVCAR8, KGN) and primary cells isolated from tumor ascites from patients with ovarian cancer. The results demonstrated that ALK2 and ALK3 may be the two main AMHRIs involved in AMH signaling at physiological endogenous and supraphysiological exogenous AMH concentrations, respectively. Supraphysiological AMH concentrations (25 nM recombinant AMH) were associated with apoptosis in all four cell lines and decreased clonogenic survival in COV434­AMHRII and SKOV3­AMHRII cells. These biological effects were induced via ALK3 recruitment by AMHRII, as ALK3­AMHRII dimerization was favored at increasing AMH concentrations. By contrast, ALK2 was associated with AMHRII at physiological endogenous concentrations of AMH (10 pM). Based on these results, tetravalent IgG1­like bispecific antibodies (BsAbs) against AMHRII and ALK2, and against AMHRII and ALK3 were designed and evaluated. In vivo, COV434­AMHRII tumor cell xenograft growth was significantly reduced in all BsAb­treated groups compared with that in the vehicle group (P=0.018 for BsAb 12G4­3D7; P=0.001 for all other BsAbs). However, the growth of COV434­AMHRII tumor cell xenografts was slower in mice treated with the anti­AMRII­ALK2 BsAb 12G4­2F9 compared with that in animals that received a control BsAb that targeted AMHRII and CD5 (P=0.048). These results provide new insights into type I receptor specificity in AMH signaling pathways and may lead to an innovative therapeutic approach to modulate AMH signaling using anti­AMHRII/anti­AMHRI BsAbs.

Bone morphogenetic protein signaling regulates skin inflammation via modulating dendritic cell function.

BACKGROUND: Bone morphogenetic proteins (BMPs) are members of the TGF-ß family that signal via the BMP receptor (BMPR) signaling cascade, distinct from canonical TGF-ß signaling. BMP downstream signaling is strongly induced within epidermal keratinocytes in cutaneous psoriatic lesions, and BMP7 instructs monocytic cells to acquire characteristics of psoriasis-associated Langerhans dendritic cells (DCs). Regulatory T (Treg)-cell numbers strongly increase during psoriatic skin inflammation and were recently shown to limit psoriatic skin inflammation. However, the factors mediating Treg-cell accumulation in psoriatic skin currently remain unknown. OBJECTIVE: We sought to investigate the role of BMP signaling in Treg-cell accumulation in psoriasis. METHODS: The following methods were used: immunohistology of patients and healthy controls; ex vivo models of Treg-cell generation in the presence or absence of Langerhans cells; analysis of BMP versus canonical TGF-ß signaling in DCs and Treg cells; and modeling of psoriatic skin inflammation in mice lacking the BMPR type 1a in CD11c+ cells. RESULTS: We here demonstrated a positive correlation between Treg-cell numbers and epidermal BMP7 expression in cutaneous psoriatic lesions and show that unlike Treg cells from healthy skin, a portion of inflammation-associated Treg cells exhibit constitutive-active BMP signaling. We further found that BMPR signaling licenses inflammation-associated Langerhans cell/DC to gain an enhanced capacity to promote Treg cells via BMPR-mediated CD25 induction and that this effect is associated with reduced skin inflammation. CONCLUSIONS: Psoriatic lesions are marked by constitutive high BMP7/BMPR signaling in keratinocytes, which instructs inflammatory DCs to gain enhanced Treg-cell-stimulatory activity. Locally secreted BMP7 can directly promote Treg-cell generation through the BMP signaling cascade.

TGF-ß-mediated enhancement of TH17 cell generation is inhibited by bone morphogenetic protein receptor 1α signaling.

The cytokines of the transforming growth factor-ß (TGF-ß) family promote the growth and differentiation of multiple tissues, but the role of only the founding member, TGF-ß, in regulating the immune responses has been extensively studied. TGF-ß is critical to prevent the spontaneous activation of self-reactive T cells and sustain immune homeostasis. In contrast, in the presence of proinflammatory cytokines, TGF-ß promotes the differentiation of effector T helper 17 (TH17) cells. Abrogating TGF-ß receptor signaling prevents the development of interleukin-17 (IL-17)-secreting cells and protects mice from TH17 cell-mediated autoimmunity. We found that the receptor of another member of TGF-ß family, bone morphogenetic protein receptor 1α (BMPR1α), regulates T helper cell activation. We found that the differentiation of TH17 cells from naive CD4+ T cells was inhibited in the presence of BMPs. Abrogation of BMPR1α signaling during CD4+ T cell activation induced a developmental program that led to the generation of inflammatory effector cells expressing large amounts of IL-17, IFN-γ, and TNF family cytokines and transcription factors defining the TH17 cell lineage. We found that TGF-ß and BMPs cooperated to establish effector cell functions and the cytokine profile of activated CD4+ T cells. Together, our data provide insight into the immunoregulatory function of BMPs.

Immunoexpression of BMP-2 and BMP-4 and their receptors, BMPR-IA and BMPR-II, in ameloblastomas and adenomatoid odontogenic tumors.

OBJECTIVES: The present study evaluated the immunohistochemical expression of BMP-2 and BMP-4 and of their receptors (BMPR-IA and BMPR-II) in solid ameloblastoma (SA), unicystic ameloblastoma (UA) and adenomatoid odontogenic tumor (AOT) in order to obtain a better understanding of their role in the development and biological behavior of these tumors. DESIGN: This study analyzed these proteins in 30 cases of SA, 10 cases of UA, and 30 cases of AOT. Immunoexpression was evaluated in the parenchyma and stroma by attributing the following scores: 0, no stained cells; 1, ≤10%; 2, >10% and ≤25%; 3, >25% and ≤50%; 4, >50% and ≤75%.; 5, >75% stained cells. RESULTS: In SAs, positive correlations were observed between the stromal and parenchymal expression of BMP-2 (p<0.001) and between the stromal expression of BMP-2 and BMP-4 (p=0.020), as well as between the stromal expression of BMPR-II and BMP-4 (p=0.001) and the stromal and parenchymal expression of BMPR-II (p<0.001). In UAs, correlations were detected between the stromal and parenchymal expression of BMP-4 (p=0.035) and between the stromal expression of BMP-4 and BMPR-IA (p=0.022). In AOTs, analysis of immunoexpression in the parenchyma revealed positive correlations between all proteins. CONCLUSION: BMPs and their receptors play an important role in the differentiation and development of ameloblastomas and AOTs, but may not explain the different biological behaviors of these lesions. The positive correlation observed in AOTs might be related to the formation of mineralized material in this tumor.

The impact of passive immunisation against BMPRIB and BMP4 on follicle development and ovulation in mice.

The primordial follicle reserve is the corner stone of female fertility and determines the longevity and quality of reproduction. Complete depletion of this reserve will lead to primary infertility, and the key-limiting step of follicle depletion is the transition from primordial to primary follicles. It has been reported that this process is gonadotrophin-independent, but other conflicting reports are indicated otherwise and this discrepancy needs to be unequivocally clarified. The aim of this study was to investigate the role of bone morphogenetic proteins (BMPs) in the regulation of folliculogenesis in mice passively immunised against BMP receptor 1B (BMPRIB) and BMP4. While a stereological study revealed that the numbers of primordial follicles in immunised mice were significantly higher when compared with control animals, treatment with equine chorionic gonadotrophin showed no effect. In parallel, immunofluorescence microscopy revealed the presence of BMPRIB but not FSH receptor in primordial follicles. The number of primary follicles in immunised mice were also significantly increased when compared with control animals. After puberty, the rates of depletion of primordial and primary follicles were increased with age, particularly in treated animals; however, there was no significant difference between the treatment groups of the same age. Based on these results together with our previous reports in sheep and mice, we confirm that the attenuation of BMP signalling system can be an effective approach to sustain the primordial follicle reserve while promoting the development of growing follicles, ovulation and consequently overall female fertility.

Modulation of bone morphogenic protein signaling in T-cells for cancer immunotherapy.

Immunotherapy is becoming an increasingly attractive therapeutic alternative for conventional cancer therapy. In recent years Foxp3(+) regulatory T-cells (T(R)) were identified as the major obstacle to effective cancer immunotherapy. The abundance of these cells in peripheral blood is increased in patients with multiple types of cancer and their prevalence among tumor-infiltrating lymphocytes correlated with poor clinical prognosis. In contrast, removal or inactivation of T(R) cells led to enhanced anti-tumor immune response and better efficacy of cancer vaccines. This study reports that Bone Morphogenic Protein Receptor 1α (BMPR1α, Alk-3) is expressed by activated effector CD4(+) and T(R) cells and modulates functions of both cell types. Bone Morphogenic Proteins (BMPs) belong to the transforming growth factor (TGF)-ß family of cytokines that also include TGFß and activins. BMPs play crucial roles in embryonic development, tissue differentiation and homeostasis, and development of cancer. It was demonstrated that BMPs and activins synergize with TGFß to regulate thymic T-cell development, maintain T(R) cells, and control peripheral tolerance. Inactivation of BMPR1α in T-cells results in impaired thymic and peripheral generation of T(R) cells. BMPR1α-deficient activated T-cells produced a higher level of interferon (IFN)-γ than BMPR1α-sufficient T-cells. Moreover, transplanted B16 melanoma tumors grew smaller in mice lacking expression of BMPR1α in T-cells and tumors had few infiltrating TR cells and a higher proportion of CD8(+) T-cells than wild-type mice.

Immunohistological localization of BMP-2, BMP-7, and their receptors in knee joints with focal cartilage lesions.

INTRODUCTION: Although it is well known that BMP-2 and BMP-7 play significant roles in cartilage metabolism, data about intra-articular expression and localization of these proteins and their receptors in humans are rare. METHODS: Biopsies of synovia and debrided cartilage were taken in patients undergoing autologous chondrocyte implantation. Expression of BMP-2, BMP-7, and their receptors BMPR-1A, BMPR-1B and BMPR-2 were semiquantitatively evaluated by immunohistological staining. RESULTS: BMP-7 was equally highly expressed in all cartilage and synovial biopsies. Increased levels of BMPR-1A, but not of BMPR-1B, and BMPR-2, were found in all synovial and 47% of all cartilage samples (P = 0.002). BMP-2 was positively scored in 47% of all cartilage and 40% of all synovial specimens. Defect size, KOSS, Henderson or Kellgren-Lawrence score did not statistically significant correlate with the expression of the analyzed proteins or Mankin and Pritzker scores. Duration of symptoms and localization of lesions were associated with KOSS (P < 0.02), but there was no influence of these parameters on protein expression. CONCLUSIONS: BMP-2, BMP-7, and BMPR-1A were expressed in cartilage and synovia of knees with focal cartilage lesions. Although defect localization and duration of symptoms decisively influence KOSS, there was no associated alteration of protein expression observed.

Crystallization of BMP receptor type IA bound to the antibody Fab fragment AbD1556.

An antibody Fab fragment, AbD1556, was selected against the extracellular domain of BMP receptor type IA, which blocks the binding of BMP-2 to BMPR-IA and thereby neutralizes BMP-2 activity. To study the mechanism by which BMPR-IA is recognized and bound by the Fab fragment, the complex of AbD1556 bound to BMPR-IA was prepared and crystallized. Crystals of this binary complex belonged to the monoclinic space group P2(1), with unit-cell parameters a=89.32, b=129.25, c=100.24 A, beta=92.27 degrees.

[BMP7 signaling via BMPR1A, BMPR1B inhibits the proliferation of lung large carcinoma NCI-H460 cell].

BACKGROUND AND OBJECTIVE: It has been demonstrated that bone morphogenetic protein 7 (BMP7) may both inhibit and enhance cell proliferation of many kinds of cancers, but the impact of BMP7 on lung cancer cells and the exact mechanisms are not clear. The aim of this study is to investigate the effect of BMP7 on proliferation of lung carcinoma cells and explore the roles of different types of I receptors in BMP7 signal transmission by blocking endogenous BMPRIs. METHODS: The levels of expression of BMPIRs (BMP7 type I receptors) mRNA in four different NSCLC (human non-small cell lung tumor) cell lines and HBE (normal human bronchial epithelial) cell were detected by RT-PCR. The responsiveness of pulmonary large carcinoma NCI-H460 cell to BMP7 treatment as well as to a combination of BMP7 and anti-BMPIRs treatment in proliferation were detected by MTT. RESULTS: RT-PCR showed that NCI-H460 cells expressed all three types of BMPIRs; MTT showed that BMP7 inhibit the proliferation of NCI-H460 cell line. Blocking endogenous BMPR1A, BMPR1B obviously reversed the inhibition of BMP7 on the proliferation of NCI-H460 cell respectively (P = 0.003, P = 0.014). Moreover, blocking both endogenous BMPR1A and BMPR1B almost offset the effect of BMP7 on the proliferation of NCI-H460 cell completely (P < 0.001). But ACVR1A blocking did not affect the proliferation of NCI-H460 cell et al (P = 0.074). CONCLUSIONS: BMP7 signaling via BMPR1A and BMPR1B inhibits the proliferation of pulmonary large carcinoma cell NCI-H460.

The cooperative effect of growth and differentiation factor-9 and bone morphogenetic protein (BMP)-15 on granulosa cell function is modulated primarily through BMP receptor II.

Growth and differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15, GDF9B) are oocyte-derived proteins essential for the growth and function of ovarian follicles. Moreover, ovine (o) GDF9 and oBMP15 cooperate to increase both (3)H-thymidine incorporation and alpha-inhibin production and to inhibit progesterone production by rat or ovine granulosa cells. Although the receptors through which these proteins act individually have been determined, the receptor(s) involved in mediating the cooperative effects of GDF9 and BMP15 is (are) unknown. In this study, the effects of the extracellular domains of the types I and II TGFbeta receptors on (3)H-thymidine incorporation by rat granulosa cells stimulated by oGDF9 and oBMP15 were investigated. Stimulation of (3)H-thymidine incorporation was completely blocked by the BMP receptor II (BMPRII) extracellular domain but unaffected by any other type II or any type I receptor. These results suggest that the initial interaction of oGDF9 and oBMP15 is with BMPRII and that a type I receptor is either recruited or already associated with BMPRII to mediate the cooperative effects of these growth factors.