A case of anti-laminin γ1 (p200) pemphigoid developed after dipeptidyl peptidase-4 inhibitor administration.

A 73-year-old man with diabetes mellitus was referred to our department for ultraviolet treatment for erythematous skin lesions with itching. On dipeptidyl peptidase-4 inhibitor (DPP-4i) sitagliptin (Januvia®) for diabetes mellitus, the erythematous skin lesions appeared and spread to the whole body. At the initial visit, erythema multiforme-like skin lesions with crusts were observed on the trunk and extremities, and the patient was suspected to have drug eruption. Histopathology demonstrated eosinophilic infiltration in the superficial dermis and inflammatory cell infiltration in the epidermis. Sitagliptin was discontinued, and erythematous lesions improved with oral prednisolone. Thereafter the patient was treated with phototherapy and  betamethasone sodium phosphate infusion for residual prurigo. However, blistering skin lesions appeared 5 months later. Histopathological findings were subepidermal blisters with eosinophilic abscess, and bullous pemphigoid was suspected. CLEIAs for autoantibodies to desmoglein 1 (Dsg1), Dsg3 and BP180 were negative. Direct immunofluorescence showed linear depositions of immunoglobulin G (IgG) and C3 at the epidermal basement membrane zone, and indirect immunofluorescence detected IgG anti-epidermal basement membrane zone antibodies, reacting with the dermal side of 1M NaCl-split normal human skin. IgG antibodies reacted with 200 kDa laminin γ1 (p200) by immunoblotting using dermal extracts. These results indicated that this patient was diagnosed with anti-laminin γ1 (p200) pemphigoid developed after DPP-4i administration. Although reports of DPP-4i-related bullous pemphigoid have accumulated, cases of anti-laminin γ1 (p200) pemphigoid developed after DPP-4i administration are rarely reported.

Anti-Laminin 332-Type Mucous Membrane Pemphigoid.

Anti-laminin (LM) 332-type mucous membrane pemphigoid (MMP) is a rare autoimmune bullous disease and was originally discovered as anti-epiligrin cicatricial pemphigoid. Anti-LM332-type MMP has clinical manifestations similar to those of other types of MMP and can only be distinguished through the detection of circulating autoantibodies against LM332. Our group and others have established a number of immunological methods with varying sensitivity and specificity for detection of anti-LM332 autoantibodies; however, none of the established methods has been widely used for clinical diagnosis. There is currently no unified standard treatment, and it is very difficult to completely cure anti-LM332-type MMP. In addition, an increasing body of evidence suggests that there may be a strong correlation between anti-LM332-type MMP and tumors. In this article, we review the current progression of diagnosis and treatment of anti-LM332-type MMP, as well as the possible correlation between anti-LM332-type MMP and tumors.

Lymph node fibroblastic reticular cells preserve a tolerogenic niche in allograft transplantation through laminin α4.

Lymph node (LN) fibroblastic reticular cells (FRCs) define LN niches and regulate lymphocyte homeostasis through producing diverse extracellular matrix (ECM) components. We examined the role of ECM laminin α4 (Lama4) using FRC-Lama4 conditional KO Pdgfrb-Cre-/- × Lama4fl/fl mice. Single-cell RNA-sequencing (scRNA-Seq) data showed the promoter gene Pdgfrb was exclusively expressed in FRCs. Depleting FRC-Lama4 reduced Tregs and dendritic cells, decreased high endothelial venules, impaired the conduit system, and downregulated T cell survival factors in LNs. FRC-Lama4 depletion impaired the homing of lymphocytes to LNs in homeostasis and after allografting. Alloantigen-specific T cells proliferated, were activated to greater degrees in LNs lacking FRC-Lama4, and were more prone to differentiate into effector phenotypes relative to the Treg phenotype. In murine cardiac transplantation, tolerogenic immunosuppression was not effective in FRC-Lama4 recipients, which produced more alloantibodies than WT. After lung transplantation, FRC-Lama4-KO mice had more severe graft rejection with fewer Tregs in their LNs. Overall, FRC-Lama4 critically contributes to a tolerogenic LN niche by supporting T cell migration, constraining T cell activation and proliferation, and promoting Treg differentiation. Hence, it serves as a therapeutic target for immunoengineering.

A laminin-based local regulatory network in the testis that supports spermatogenesis.

In adult rat testes, the basement membrane is structurally constituted by laminin and collagen chains that lay adjacent to the blood-testis barrier (BTB). It plays a crucial scaffolding role to support spermatogenesis. On the other hand, laminin-333 comprised of laminin-α3/ß3/γ3 at the apical ES (ectoplasmic specialization, a testis-specific cell-cell adherens junction at the Sertoli cell-step 8-19 spermatid interface) expressed by spermatids serves as a unique cell adhesion protein that forms an adhesion complex with α6ß1-integrin expressed by Sertoli cells to support spermiogenesis. Emerging evidence has shown that biologically active fragments are derived from basement membrane and apical ES laminin chains through proteolytic cleavage mediated by matrix metalloproteinase 9 (MMP9) and MMP2, respectively. Two of these laminin bioactive fragments: one from the basement membrane laminin-α2 chain called LG3/4/5-peptide, and one from the apical ES laminin-γ3 chain known as F5-peptide, are potent regulators that modify cell adhesion function at the Sertoli-spermatid interface (i.e., apical ES) but also at the Sertoli cell-cell interface designated basal ES at the blood-testis barrier (BTB) with contrasting effects. These findings not only highlight the physiological significance of these bioactive peptides that create a local regulatory network to support spermatogenesis, they also open a unique area of research. For instance, it is likely that several other bioactive peptides remain to be identified. These bioactive peptides including their downstream signaling proteins and cascades should be studied collectively in future investigations to elucidate the underlying mechanism(s) by which they coordinate with each other to maintain spermatogenesis. This is the goal of this review.

A longitudinal study of antibody responses to selected host antigens in rheumatic fever and rheumatic heart disease.

Introduction. Group A streptococci can trigger autoimmune responses that lead to acute rheumatic fever (ARF) and rheumatic heart disease (RHD).Gap Statement. Some autoantibodies generated in ARF/RHD target antigens in the S2 subfragment region of cardiac myosin. However, little is known about the kinetics of these antibodies during the disease process.Aim. To determine the antibody responses over time in patients and healthy controls against host tissue proteins - cardiac myosin and peptides from its S2 subfragment, tropomyosin, laminin and keratin.Methodology. We used enzyme-linked immunosorbent assays (ELISA) to determine antibody responses in: (1) healthy controls; (2) patients with streptococcal pharyngitis; (3) patients with ARF with carditis and (4) patients with RHD on penicillin prophylaxis.Results. We observed significantly higher antibody responses against extracellular proteins - laminin and keratin in pharyngitis group, patients with ARF and patients with RHD when compared to healthy controls. The antibody responses against intracellular proteins - cardiac myosin and tropomyosin were elevated only in the group of patients with ARF with active carditis. While the reactivity to S2 peptides S2-1-3, 8-11, 14, 16-18, 21-22 and 32 was higher in patients with ARF, the reactivity in the RHD group was high only against S2-1, 9, 11, 12 when compared to healthy controls. The reactivity against S2 peptides reduced as the disease condition stabilized in the ARF group whereas the reactivity remained unaltered in the RHD group. By contrast antibodies against laminin and keratin persisted in patients with RHD.Conclusion. Our findings of antibody responses against host proteins support the multistep hypothesis in the development of rheumatic carditis. The differential kinetics of serum antibody responses against S2 peptides may have potential use as markers of ongoing cardiac damage that can be used to monitor patients with ARF/RHD.

Laminin-521 is a Novel Target of Autoantibodies Associated with Lung Hemorrhage in Anti-GBM Disease.

BACKGROUND: Antiglomerular basement membrane (anti-GBM) disease is characterized by GN and often pulmonary hemorrhage, mediated by autoantibodies that typically recognize cryptic epitopes within α345(IV) collagen-a major component of the glomerular and alveolar basement membranes. Laminin-521 is another major GBM component and a proven target of pathogenic antibodies mediating GN in animal models. Whether laminin-521 is a target of autoimmunity in human anti-GBM disease is not yet known. METHODS: A retrospective study of circulating autoantibodies from 101 patients with anti-GBM/Goodpasture's disease and 85 controls used a solid-phase immunoassay to measure IgG binding to human recombinant laminin-521 with native-like structure and activity. RESULTS: Circulating IgG autoantibodies binding to laminin-521 were found in about one third of patients with anti-GBM antibody GN, but were not detected in healthy controls or in patients with other glomerular diseases. Autoreactivity toward laminin-521 was significantly more common in patients with anti-GBM GN and lung hemorrhage, compared with those with kidney-limited disease (51.5% versus 23.5%, P=0.005). Antilaminin-521 autoantibodies were predominantly of IgG1 and IgG4 subclasses and significantly associated with lung hemorrhage (P=0.005), hemoptysis (P=0.008), and smoking (P=0.01), although not with proteinuria or serum creatinine at diagnosis. CONCLUSIONS: Besides α345(IV) collagen, laminin-521 is another major autoantigen targeted in anti-GBM disease. Autoantibodies to laminin-521 may have the potential to promote lung injury in anti-GBM disease by increasing the total amount of IgG bound to the alveolar basement membranes.

Antibodies to an Epstein Barr Virus protein that cross-react with dsDNA have pathogenic potential.

Pathogens such as the Epstein Barr virus (EBV) have long been implicated in the etiology of systemic lupus erythematosus (SLE). The Epstein Barr virus nuclear antigen I (EBNA-1) has been shown to play a role in the development of anti-nuclear antibodies characteristic of SLE. One mechanism by which EBV may play a role in SLE is molecular mimicry. We previously generated two monoclonal antibodies (mAbs) to EBNA-1 and demonstrated that they cross-react with double-stranded DNA (dsDNA). In the present study, we demonstrate that these mAbs have pathogenic potential. We show that they can bind to isolated rat glomeruli and that binding can be greatly diminished by pretreatment of glomeruli with DNase I, suggesting that these mAbs bind dsDNA in the kidney. We also demonstrate that these antibodies can deposit in the kidney when injected into mice and can induce proteinuria and elicit histopathological alterations consistent with glomerulonephritis. Finally, we show that these antibodies can cross-react with laminin and collagen IV in the extracellular matrix suggesting that direct binding to the glomerular basement membrane or mesangial matrix may also contribute to the antibody deposition in the kidney. In summary, our results indicate that EBNA-1 can elicit antibodies that cross-react with dsDNA, that can deposit in the kidney, and induce kidney damage. These results are significant because they support the role of a viral protein in SLE and lupus nephritis.

Self-assembling peptide hydrogels functionalized with LN- and BDNF- mimicking epitopes synergistically enhance peripheral nerve regeneration.

The regenerative capacity of the peripheral nervous system is closely related to the role that Schwann cells (SCs) play in construction of the basement membrane containing multiple extracellular matrix proteins and secretion of neurotrophic factors, including laminin (LN) and brain-derived neurotrophic factor (BDNF). Here, we developed a self-assembling peptide (SAP) nanofiber hydrogel based on self-assembling backbone Ac-(RADA)4-NH2 (RAD) dual-functionalized with laminin-derived motif IKVAV (IKV) and a BDNF-mimetic peptide epitope RGIDKRHWNSQ (RGI) for peripheral nerve regeneration, with the hydrogel providing a three-dimensional (3D) microenvironment for SCs and neurites. Methods: Circular dichroism (CD), atomic force microscopy (AFM), and scanning electron microscopy (SEM) were used to characterize the secondary structures, microscopic structures, and morphologies of self-assembling nanofiber hydrogels. Then the SC adhesion, myelination and neurotrophin secretion were evaluated on the hydrogels. Finally, the SAP hydrogels were injected into hollow chitosan tubes to bridge a 10-mm-long sciatic nerve defect in rats, and in vivo gene expression at 1 week, axonal regeneration, target muscular re-innervation, and functional recovery at 12 weeks were assessed. Results: The bioactive peptide motifs were covalently linked to the C-terminal of the self-assembling peptide and the functionalized peptides could form well-defined nanofibrous hydrogels capable of providing a 3D microenvironment similar to native extracellular matrix. SCs displayed improved cell adhesion on hydrogels with both IKV and RGI, accompanied by increased cell spreading and elongation relative to other groups. RSCs cultured on hydrogels with IKV and RGI showed enhanced gene expression of NGF, BDNF, CNTF, PMP22 and NRP2, and decreased gene expression of NCAM compared with those cultured on other three groups after a 7-day incubation. Additionally, the secretion of NGF, BDNF, and CNTF of RSCs was significantly improved on dual-functionalized peptide hydrogels after 3 days. At 1 week after implantation, the expressions of neurotrophin and myelin-related genes in the nerve grafts in SAP and Autograft groups were higher than that in Hollow group, and the expression of S100 in groups containing both IKV and RGI was significantly higher than that in groups containing either IKV or RGI hydrogels, suggesting enhanced SC proliferation. The morphometric parameters of the regenerated nerves, their electrophysiological performance, the innervated muscle weight and remodeling of muscle fibers, and motor function showed that RAD/IKV/RGI and RAD/IKV-GG-RGI hydrogels could markedly improve axonal regeneration with enhanced re-myelination and motor functional recovery through the synergetic effect of IKV and RGI functional motifs. Conclusions: We found that the dual-functionalized SAP hydrogels promoted RSC adhesion, myelination, and neurotrophin secretion in vitro and successfully bridged a 10-mm gap representing a sciatic nerve defect in rats in vivo. The results demonstrated the synergistic effect of IKVAV and RGI on axonal regrowth and function recovery after peripheral nerve injury.

Alterations in the immunoreactivity of laminin, type IV collagen and α3ß1 integrin in diabetic rat ovarian follicles.

AIM: In order to determine the possible effects of diabetes, we aimed to investigate the expression of extracellular matrix proteins in the theca and granulosa layers in different follicular stages. METHODS: Thirty-two adult Wistar albino male rats were divided into 4 groups as control and sampled groups. Four, eight and twelve weeks after inducing diabetes with an intraperitoneal injection of streptozotocin (40 mg/kg), the expressions of laminin, type IV collagen and α3ß1 integrin in ovarian tissues were evaluated by immunohistochemical method. RESULTS: In our study, in the first month of diabetes, a significant increase was observed in laminin, type IV collagen and α3ß1 integrin expressions in all follicle types compared to the control group in both the theca and granulosa layers. Laminin and type IV collagen immunoreactivity tended to increase in D2 and D3 groups also. Integrin expression did not change in the newly formed follicles in the D2 and D3 groups, however, it tended to change and increase in the developing follicles. CONCLUSIONS: The changes in the expression of laminin, type IV collagen and α3ß1 integrin, which are the extracellular matrix proteins in the follicle, along with diabetes, show that diabetes plays a role in the regulation of follicular development (Tab. 4, Fig. 36, Ref. 29).

The lymph node stromal laminin α5 shapes alloimmunity.

Lymph node stromal cells (LNSCs) regulate immunity through constructing lymphocyte niches. LNSC-produced laminin α5 (Lama5) regulates CD4+ T cells but the underlying mechanisms of its functions are poorly understood. Here we show that depleting Lama5 in LNSCs resulted in decreased Lama5 protein in the LN cortical ridge (CR) and around high endothelial venules (HEVs). Lama5 depletion affected LN structure with increased HEVs, upregulated chemokines, and cell adhesion molecules, and led to greater numbers of Tregs in the T cell zone. Mouse and human T cell transendothelial migration and T cell entry into LNs were suppressed by Lama5 through the receptors α6 integrin and α-dystroglycan. During immune responses and allograft transplantation, depleting Lama5 promoted antigen-specific CD4+ T cell entry into the CR through HEVs, suppressed T cell activation, and altered T cell differentiation to suppressive regulatory phenotypes. Enhanced allograft acceptance resulted from depleting Lama5 or blockade of T cell Lama5 receptors. Lama5 and Lama4/Lama5 ratios in allografts were associated with the rejection severity. Overall, our results demonstrated that stromal Lama5 regulated immune responses through altering LN structures and T cell behaviors. This study delineated a stromal Lama5-T cell receptor axis that can be targeted for immune tolerance modulation.

biAb Mediated Restoration of the Linkage between Dystroglycan and Laminin-211 as a Therapeutic Approach for α-Dystroglycanopathies.

Patients with α-dystroglycanopathies, a subgroup of rare congenital muscular dystrophies, present with a spectrum of clinical manifestations that includes muscular dystrophy as well as CNS and ocular abnormalities. Although patients with α-dystroglycanopathies are genetically heterogeneous, they share a common defect of aberrant post-translational glycosylation modification of the dystroglycan alpha-subunit, which renders it defective in binding to several extracellular ligands such as laminin-211 in skeletal muscles, agrin in neuromuscular junctions, neurexin in the CNS, and pikachurin in the eye, leading to various symptoms. The genetic heterogeneity associated with the development of α-dystroglycanopathies poses significant challenges to developing a generalized treatment to address the spectrum of genetic defects. Here, we propose the development of a bispecific antibody (biAb) that functions as a surrogate molecular linker to reconnect laminin-211 and the dystroglycan beta-subunit to ameliorate sarcolemmal fragility, a primary pathology in patients with α-dystroglycan-related muscular dystrophies. We show that the treatment of LARGEmyd-3J mice, an α-dystroglycanopathy model, with the biAb improved muscle function and protected muscles from exercise-induced damage. These results demonstrate the viability of a biAb that binds to laminin-211 and dystroglycan simultaneously as a potential treatment for patients with α-dystroglycanopathy.

[Anti-p200 pemphigoid: clinical, diagnostic and therapeutic aspects]. / Anti-p200-Pemphigoid: Klinik, Diagnostik, Therapie.

Anti-p200 pemphigoid is a rare autoimmune blistering dermatosis. The clinical course is heterogeneous. Typically, immunoglobulin G (IgG) antibodies are found on the floor of salt-split skin, which differentiates p200 pemphigoid from bullous pemphigoid. It is necessary to perform immunoblotting and enzyme-linked immunosorbent assays (ELISA) to confirm the diagnosis. Small amounts of dapsone are often sufficient for disease control. The clinical and diagnostic characteristics of anti-p200 pemphigoid and the principles of treatment are presented exemplified by two case reports.

Anti-p200 Pemphigoid: A Systematic Review.

The many clinical aspects of anti-p200 pemphigoid are not well-characterized. We aimed to analyze and correlate known existing data on the epidemiological, clinical, histological, and immunological features of anti-p200 pemphigoid. We performed a review using Medline, Embase, and Web of Science databases (1900-2018). Case reports and series of patients were included. A total of 68 eligible studies that comprised 113 anti-p200 pemphigoid patients were included in the qualitative analysis, where there was a mean age of onset of 65.5 years. All patients presented with bullae/vesicles, and 54.3% had urticarial plaques. A similarity to bullous pemphigoid was reported in 66.1% of cases, but palmoplantar (51.4%), cephalic (40.3%), and mucosal (38.5%) involvement, besides frequent development of scars/milia (15.7%), were reported. Autoantibodies against recombinant laminin γ1 were detected in the sera of 73.1% of patients. Psoriasis was present in 28.3% of anti-p200 pemphigoid patients, particularly among Japanese patients (56.4%). The incidence of pustular psoriasis in this subgroup, was significantly greater than in the normal population. In conclusion, the diagnosis of anti-p200 pemphigoid may be suspected when a subepidermal autoimmune blistering disease develops in a younger age group, along with significant acral and cephalic distribution and mucosal involvement.

Maternal alloimmune IgG causes anti-glomerular basement membrane disease in perinatal transgenic mice that express human laminin α5.

Mammalian immune systems are not mature until well after birth. However, transfer of maternal IgG to the fetus and newborn usually provides immunoprotection from infectious diseases. IgG transfer occurs before birth in humans across the placenta and continues after birth across the intestine in many mammalian species, including rodents. Transfer, which is mediated by the neonatal IgG Fc receptor, occurs by transcytosis across placental syncytiotrophoblasts and intestinal epithelium. Although maternal IgG is generally beneficial, harmful maternal allo- and autoantibodies can also be transferred to the fetus/infant, resulting in serious disease. To test this we generated transgenic mice that widely express human laminin α5 in their basement membranes. When huLAMA5 transgenic males were crossed with wild-type females, there was a maternal anti-human laminin α5 immune response. Maternal IgG alloantibody crossed the yolk sac and post-natal intestine invivo and bound in bright, linear patterns to kidney glomerular basement membranes of transgenic fetuses/neonates but not those of wild-type siblings. By postnatal day 18, most transgenic mice were proteinuric, had glomerular C3 deposits and inflammatory cell infiltrates, thickened and split glomerular basement membranes, and podocyte foot process effacement. Thus, our novel model of perinatal anti-glomerular basement membrane disease may prove useful for studying pediatric glomerulopathies, formation of the fetomaternal interface, and maternal alloimmunization.