Therapy for α1-Antitrypsin Deficiency

alpha(1)-Antitrypsin (A1AT) deficiency is inherited as an autosomal codominant disorder characterised by reduced levels of A1AT in the serum. Low levels of A1AT in blood perfusing the lung cause low levels in the lung interstitium, making it susceptible to proteolytic damage from resident neutrophil elastase. A 'protective threshold' serum A1AT level of 11 micromol/L has been identified by epidemiological studies as a minimum value below which there is an increased risk of emphysema. Intravenous augmentation therapy for patients with severe deficiency of A1AT has been shown to have biochemical efficacy. Although the clinical efficacy of intravenous augmentation therapy has not been demonstrated in a randomised clinical trial, available studies suggest that augmentation therapy is associated with a slowed rate of decline of lung function and enhanced survival. The criteria for patient selection include: age >18 years, serum A1AT level 相似文献   

Conversion of Arterial Smooth Muscle Phenotype in Human fetus and Adult

During recent years,it has become increasingly evident that there are obvious differences inthe ultrastructure of arterial smooth muscle cellsbetween fetuses and adults.To further characterize the ultrastructure of arterial smooth cells inhuman fetuses and adults,10 specimens of fetusesand 6 specimens of adults from aorta were collected.Moreover, 4 specimens of atherosclerosisplaques from adult aorta were taken. All thespecimens were processed for electron microscopy.We observed that the smooth muscle cells in fetues showed fibroblast-like appearance with intensive rough endoplasmic reticulum, a prominent     

Immunosuppressive Drugs Alter α1-Antitrypsin Production in Hepatocytes: Implications for Epithelial Gap Repair

Immunosuppressive drugs are an inherent component of hematopoietic stem cell transplantation (HSCT) for the prevention of acute graft-versus-host disease (GVHD). Circulating α1-antitrypsin (AAT), a serine-protease inhibitor produced predominantly by hepatocytes that rises during acute phase responses, is lost in patient's stool due to gastrointestinal GVHD, and its augmentation has been found to attenuate GVHD. Here we explored the effect of immunosuppressive drugs on hepatocyte production of AAT and intestinal epithelial gap repair. The effect of commonly used immunosuppressants on AAT production was examined in vitro using HepG2 cells and primary mouse hepatocytes, and their impact on human intestinal epithelial cell line gap repair was evaluated. Sera from 12 allogeneic HSCT recipients, obtained at 14 days post-transplantation, predating the diagnosis of GVHD (n = 6), were examined for reepithelialization, with added clinical-grade AAT. Rapamycin compromised AAT production under inflammatory conditions. Mycophenolate mofetil and cyclosporine A (CSA) inhibited reepithelialization; AAT minimized the effect of CSA. Patient sera displayed superior gap repair with exogenous AAT. Functional insufficiency in circulating AAT may be the result of drug toxicities leading to ineffective gut reepithelization and compromised gut lining. Taken together, our data strengthen the rationale for incorporating AAT augmentation therapy into immunosuppressive treatment protocols.     

α4β1 and α5β1 Control Cell Migration on Fibronectin by Differentially Regulating Cell Speed and Motile Cell Phenotype

Computer-aided time lapse fluorescence videomicroscopy was used to study single cell migration behavior of human aortic endothelial cells on fibronectin coated substrates of varying protein surface density. The role of receptors _₅ _₁, __v _₃, and ₄₁ in mediating cell adhesion and migration on fibronectin was characterized using integrin specific monoclonal antibodies. Matrix density had a direct effect on controlling the proportion of migrating cells and the directional persistence of cell movement (p < 0.01). While there was relatively little influence of fibronectin surface density on absolute migration speed, the ability of endothelial cells to disperse over a surface, as measured by the dispersion coefficient, was biphasic with respect to the surface density of this matrix protein (p < 0.005). Both cell speed and the proportion of migrating cells was controlled by ₄₁ (p < 0.01). However, ₅₁ selectively regulated the transformation of stationary cells to those exhibiting motile behavior (p <0.05). Migratory responses on fibronectin were not influenced by blockade of the _v3 receptor. It is noteworthy that cell surface adhesive receptors which control commitment to a motile phenotype are not necessarily the same as those that control migration speed. © 1998 Biomedical Engineering Society. PAC98: 8722-q     

Human-Derived α1-Antitrypsin is Still Efficacious in Heavily Pretreated Patients with Steroid-Resistant Gastrointestinal Graft-versus-Host Disease

Almost one-half of patients developing graft-versus-host disease (GVHD) will not respond to standard first-line steroid treatment. Alpha-1 antitrypsin (AAT) is able to induce tolerance in preclinical models of GVHD. AAT alters the cytokine milieu, promotes a tolerogenic shift of dendritic cells, and skews effector T cells toward regulatory T cells. Gastrointestinal steroid-refractory (SR)-GVHD is a protein-losing enteropathy that might represent the optimal setting in which to use AAT. Here we analyze the outcomes of 16 patients treated with human-derived AAT in advanced-stage gut SR-GVHD, with two-thirds of the patients having failed at least 1 treatment for SR-GVHD. The overall response rate (ORR) was 44%, with a complete response (CR) rate of 27%. Gastrointestinal response was observed in 61% of patients. The median time to best response was 21 days (range, 6 to 26 days). At day 56 after AAT treatment, all CRs were maintained, and the ORR was 39%. The 1-year overall survival was 48% (95% confidence interval, 26% to 74%). Ancillary studies showed that AAT serum levels were in the normal range at the beginning of treatment, whereas fecal loss was elevated. AAT levels consistently rose after exogenous administration, but no correlation was found between serum levels and response. REG3α and IL-33 levels were associated with response while, in contrast to previous reports, regulatory T cells decreased during AAT treatment. This retrospective analysis supports a previous report of AAT as a promising agent in the management of gut SR-GVHD and should prompt its evaluation at an earlier stage.     

Serum α1-antitrypsin and α2-macroglobulin in Alzheimer's and Binswanger's disease

The deposition of _A4-amyloid in senile plaques and small cerebral vessels is one of the pathological hallmarks of Alzheimer's disease. Recent data suggest that protease inhibitors such as ₂-macroglobulin may be involved in the process of forming _A4 amyloid deposits. Compared to 34 persons without neurological diseases, the serum content of al-antitrypsin was increased in 16 patients with Alzheimer's disease and 15 with Binswanger's disease. In the latter a2 macroglobulin was also elevated in serum. Our results show no evidence of a blood-borne origin of the protein or peptid deposited in the walls of small vessels in Alzheimer's or Binswanger's disease. Nevertheless, the elevated proteinase inhibitor concentrations may play a role in the pathogenesis of these diseases.Abbreviations AD Alzheimer's disease - APP -amyloid peptide precursor peptide - BD Binswanger's disease - IMCT Information-Memory-Concentration Test - MID multi-infarct dementia - MMSE Mini-Mental State Examination Correspondence to: T. Wetterling     

Integrin α1/β1 and α2/β1 as a receptor for IgA1 in human glomerular mesangial cells in IgA nephropathy

IgA nephropathy (IgAN) is characterized by mesangial deposition of IgA1 and galactose-deficient IgA1 is expected to play a pathogenic role. However, the identity of the receptor for IgA1 is still controversial. Hence, the aim of this study was to explore the receptor for galactose-deficient IgA1. Human monoclonal IgA1 was treated with exoglycosidase and FITC-conjugated control, asialo- and agalactosyl-IgA1 was used as a probe to detect the receptor in cultured human mesangial cells. Tumor necrosis factor-α or transforming growth factor-β1 treatment accelerated IgA1-binding on mesangial cells, and these effects were diminished by the addition of dexamethasone, whereas these changes were not dependent on galactose-deficiency of IgA1. According to comprehensive gene expression analysis, we focused on integrin β1. Pre-treatment by Mn(2+), which activates integrin by changing its structure, enhanced the binding of IgA1 in cultured mesangial cells. Furthermore, pre-incubation with collagens specifically enhanced binding of IgA1 in the cultured human mesangial cells without activation by Mn(2+). Collagen type IV distributed in the mesangial region of the glomeruli as well as Bowman's capsule and tubular basal membrane in IgAN patients, and the IgA1 with collagen type IV induced proliferative signals on mesangial cells by phosphorylating extracellular signal-regulated kinase more effectively than the IgA1 alone. Immunoprecipitation assay revealed the binding of IgA1 and integrin α1/β1 and α2/β1 heterodimer and down-regulation of integrin α1, α2 and β1 expression in human mesangial cells induced by each specific small interfering RNA diminished the ability to bind IgA1 probe. Integrin α1/β1 and α2/β1 would be a candidate receptor for IgA1.     

Synoviocytes in chronic synovitis in situ and cytokine stimulated synovial cells in vitro neo-express α1, α3 and α5 chains of β1 integrins

The expression of the 1 integrins was examined immunohistochemically in synoviocytes from normal synovial membrane and from chronic synovitis of different aetiology and intensity. Normal synoviocytes were 61-positive but lacked 1 through 5. In mild inflammation type A synoviocytes neo-expressed 1, 3, and 5 chains. In severe inflammation both type A and B synoviocytes expressed 3, 4, 5, and 6 chains. The effects of inflammatory cytokines, as single agents or in combination, on the 1 integrin expression in cultured normal synoviocytes was determined by immunocytochemistry and flow cytometry. The 1 chain, while absent in unstimulated synoviocytes, was induced by interleukin-1 (IL-1), tumour necrosis factor- (TNF-), and interferon- (INF-). This effect was enhanced by combining IL-1 and TNF-. Expression of the 3 chain was up-regulated by IL-1 and, more intensely, by IFN-. Transforming growth factor (TGF-) inhibited the up-regulating effect of IL-1 and antagonized the effect of IFN- on 3 chain expression. Expression of the 5 chain was up-regulated significantly by co-stimulation through IL-1 together with TGF- or TNF-. Thus, the 1 integrin profile of cytokine activated synoviocytes in vitro resembled that of synoviocytes in synovitis in situ. These data suggest that IL-1, TNF-, IFN-, and TGF- are likely to be among the effectors regulating 1 integrin expression in synoviocytes in vivo.     

A Key Role for the Integrin α2β1 in Experimental and Developmental Angiogenesis

The α2β1 integrin receptor plays a key role in angiogenesis. Here we investigated the effects of small molecule inhibitors (SMIs) designed to disrupt integrin α2 I or β1 I-like domain function on angiogenesis. In unchallenged endothelial cells, fibrillar collagen induced robust capillary morphogenesis. In contrast, tube formation was significantly reduced by SMI496, a β1 I-like domain inhibitor and by function-blocking anti-α2β1 but not -α1β1 antibodies. Endothelial cells bound fluorescein-labeled collagen I fibrils, an interaction specifically inhibited by SMI496. Moreover, SMI496 caused cell retraction and cytoskeletal collapse of endothelial cells as well as delayed endothelial cell wound healing. SMI activities were examined in vivo by supplementing the growth medium of zebrafish embryos expressing green fluorescent protein under the control of the vascular endothelial growth factor receptor-2 promoter. SMI496, but not a control compound, interfered with angiogenesis in vivo by reversibly inhibiting sprouting from the axial vessels. We further characterized zebrafish α2 integrin and discovered that this integrin is highly conserved, especially the I domain. Notably, a similar vascular phenotype was induced by morpholino-mediated knockdown of the integrin α2 subunit. By live videomicroscopy, we confirmed that the vessels were largely nonfunctional in the absence of α2β1 integrin. Collectively, our results provide strong biochemical and genetic evidence of a central role for α2β1 integrin in experimental and developmental angiogenesis.Angiogenesis is the formation of new capillaries from pre-existing blood vessels and is essential for human development, wound healing, and tissue regeneration.¹ Angiogenesis is dependent on interactions of endothelial cells with growth factors and extracellular matrix components.^2,3 Endothelial cell-collagen interactions are thought to play a role in angiogenesis in vivo and in vitro and require the function of the α1β1 and α2β1 integrins,³ two receptors known to cross talk.⁴ Thus, vascular endothelial growth factor (VEGF)-induced angiogenesis in Matrigel plugs implanted in mice is markedly inhibited by anti-α1β1 and -α2β1 integrin antibodies.^5,6 Studies using various collagen-induced angiogenesis assays also suggest a critical role for endothelial cell α2β1 integrin^2,7,8 binding to the GFPGER_502–507 sequence of the collagen triple helix.⁹ Consistent with these findings, endorepellin, a potent anti-angiogenic molecule derived from the C terminus of perlecan^10,11 disrupts α2β1 integrin function,^{12,13,14,15,16} and some of the affected gene products have been associated with the integrin-mediated angiogenesis.¹⁷ Endothelial cell-collagen interactions may also contribute to tumor-associated angiogenesis.¹⁸ For example, gene products up-regulated in tumor-associated endothelial cells include types I, III, and VI collagens,¹⁹ and tumor-associated angiogenesis is sensitive to endorepellin treatment.^15,20,21Interestingly, α2β1 integrin-null mice show no overt alteration in either vasculogenesis or angiogenesis but display only a mild platelet dysfunction phenotype and altered branching morphogenesis of the mammary glands.^22,23 This observation suggests that in mammals, there is functional compensation during development, but that α2β1 integrin might be required for postnatal angiogenesis. Indeed, when adult α2β1-null mice are experimentally challenged, they show an enhanced angiogenic response during wound healing²⁴ and tumor xenograft development.^15,25The α1β1 and α2β1 integrins include inserted domains (I domains) in their α subunits that mediate ligand binding.^26,27 The α2 I domain is composed of a Rossman fold and a metal ion coordination site (MIDAS), proposed to ligate the GFPGER_502–507 sequence of collagen, thereby inducing receptor activation.^26,28 Other integrin domains may also play a role in ligand binding and receptor activation. For example, the β1 I-like domain seems to allosterically modulate collagen ligation by the α2 I domain, and, intracellularly, the cytoplasmic sequence of the α2 subunit functions as a hinge, locking the receptor in an inactive conformation, and membrane-soluble peptide mimetics of this sequence were shown to promote α2β1 receptor activation.²⁹ Recently, a family of small molecule inhibitors (SMIs)² targeting the function of the α2β1 integrin were designed.³⁰ Specifically, inhibitors of α2β1 integrin function were prepared using modular synthesis, enabling substitutions of arylamide scaffold backbones with various functional groups, creating SMIs targeted to the I domain or the intact integrin.^30,31,32 In this study, we tested the activities of a group of SMIs on endothelial cell-collagen interactions and angiogenesis in vitro and in vivo. We provide evidence that SMI496, which binds between the I domains of β1 and α2 subunits,³² interferes with α2β1 integrin activity on endothelial cells both in vitro and in vivo, suggesting a potential therapeutic modality to interfere with angiogenesis. Moreover, interference with α2 integrin expression in embryonic zebrafish caused a vascular phenotype characterized by abnormal angiogenesis.     

Vascular Damages in Rats Immunized by α_1-Adrenoceptor Peptides

Autoantibodies against the α1-adrenoceptor which had agonist activity as norepinephrine might play roles in the progression of hypertension, but whether the autoantibodies could induce vascular remodeling as norepinephrine is not clear. In this paper, the models with antibodies against the α1-adrenoceptor were made by immunizing Wistar rats with the synthesized the second extracellular loop of α1-adrenoceptor peptides. The homo-age male Wistar rats received BSA in the same immunizing manner and male spontan...     

Sleep and circadian rhythms in α-synucleinopathies—Perspectives for disease modification

The global north is facing an unprecedented rise in the prevalence of neurodegenerative diseases. The increasing incidence of Parkinson's disease is being referred to as a pandemic. The reason for the enormous increase is only partly understood. Lifestyle factors are known to play a role, but they alone cannot account for the surge. One factor that—although being recognized as important—has not been explored in detail so far is the influence of circadian rhythms. Sleep and circadian rhythm disruption are known as key factors in neurodegeneration, and their occurrence during early disease stages suggests a causal role in the pathogenesis. Isolated rapid eye movement (REM) sleep behavior disorder (iRBD) has been identified as a prodromal state of α-synucleinopathies, such as Parkinson's disease, Lewy body dementia, and multiple system atrophy offering a window for insights into the early development of these diseases. Even though REM sleep is the sleep state most pronounced, driven and modulated by the circadian timing system, specific circadian abnormalities have not been described in iRBD. Novel experimental and clinical approaches exploiting the molecular circuitry underlying circadian timekeeping hold promise to disentangle some of the pathophysiologic mechanisms of α-synucleinopathies. In this review, we summarize current knowledge on sleep and circadian rhythm disruptions in α-synucleinopathies with an emphasis on molecular aspects and therapeutic potentials. These insights might contribute to our understanding of the pathogenesis of neurodegenerative diseases and may allow therapeutic interventions addressing the disturbed circadian system at the early stage of disease.     

Differential pathways for interleukin-1β production activated by chromogranin A and amyloid β in microglia

Although chromogranin A (CGA) is frequently present in Alzheimer's disease (AD), senile plaques associated with microglial activation, little is known about basic difference between CGA and fibrillar amyloid-β (fAβ) as neuroinflammatory factors. Here we have compared the interleukin-1β (IL-1β) production pathways by CGA and fAβ in microglia. In cultured microglia, production of IL-1β was induced by CGA, but not by fAβ. CGA activated both nuclear factor–κB (NF-κB) and pro–caspase-1, whereas fAβ activated pro–caspase-1 only. For the activation of pro–caspase-1, both CGA and fAβ needed the enzymatic activity of cathepsin B (CatB), but only fAβ required cytosolic leakage of CatB and the NLRP3 inflammasome activation. In contrast, fAβ induced the IL-1β secretion from microglia isolated from the aged mouse brain. In AD brain, highly activated microglia, which showed intense immunoreactivity for CatB and IL-1β, surrounded CGA-positive plaques more frequently than Aβ-positive plaques. These observations indicate differential pathways for the microglial IL-1β production by CGA and fAβ, which may aid in better understanding of the pathological significance of neuroinflammation in AD.     

HGF suppresses the production of collagen type III and α-SMA induced by TGF-β1 in healing fibroblasts

The aim of this study was to examine the effectiveness of HGF in blocking TGF-beta1-induced collagen III and alpha-smooth muscle actin (alpha-SMA) production in rat healing fibroblasts, fibroblasts were obtained from healing medial collateral ligament (MCL) injury. Cell culture was supplemented with 5 ng/ml of TGF-beta1 along with increasing doses of HGF (10-40 ng/ml). The productions of collagen III in supernatants culture were assayed by enzyme-linked immunosorbent assay. Expression of alpha-SMA was assessed by Western blot. Treatment with TGF-beta1 significantly stimulated collagen III and alpha-SMA production in healing fibroblasts. Remarkably, the addition of HGF reduced productions of all components induced by TGF-beta1 in a dose-dependent manner. This study shows that HGF antagonizes the action of TGF-beta1 effectively in cultured healing MCL injury fibroblasts. The results provide a cellular and molecular basis for HGF's acting as a therapeutic agent for MCL scar formation and poor healing.     

Inactivation of α1-proteinase inhibitor by Cu(II) and hydrogen peroxide

When ₁-proteinase inhibitor was treated with 1–5 M CuSO₄ in the presence of H₂O₂ (250–1000 M), its elastase inhibitory capacity was markedly decreased. Several other metal ions tested had either very little or no effect. The Cu(II)-catalyzed decrease in the inhibition of elastase activity can also be demonstrated in dialyzed plasma. These results are consistent with the hypothesis that in several pathological conditions in which extracellular copper levels are elevated, Cu(II)-catalyzed peroxidation of ₁-proteinase inhibitor may occur at sites of inflammation where H₂O₂ is secreted as a major product by activated phagocytes.