Increased prevalence of the alpha-1-antitrypsin (A1AT) deficiency-related S gene in patients infected with human immunodeficiency virus type 1

Identification of citrullinated α1-antitrypsin (A1AT) in saliva in a mouse model of rheumatoid arthritis

OBJECTIVES

Rheumatoid arthritis (RA) is an autoimmune disease characterized by progressive joint destruction. Early diagnosis and treatment, before joint deformation or destruction occurs, are crucial. Identifying novel biomarkers for RA in saliva could potentially enable early detection of the disease, prior to its onset.

METHODS

We conducted a comprehensive proteomic analysis of salivary proteins in a mouse model of RA. Proteins were identified using western blotting and enzyme-linked immunosorbent assay in the serum, saliva, and ankle joints of DBA/1JJmsSlc mice, a model of RA. Ankle joints and submandibular glands were stained with hematoxylin and eosin and immunostained, and the results were compared with those of control mice.

RESULTS

Citrullinated alpha-1 antitrypsin (A1AT, 46 kDa) was commonly detected in the saliva, serum, and ankle joints of mice with severe RA and was confirmed through proteomic analysis. Western blotting showed a band corresponding to 46 kDa in the serum, saliva, and ankle joints. Immunostaining of the ankle joints with the A1AT antibody showed a strong positive signal in the synovium.

CONCLUSIONS

In DBA/1JJmsSlc mice, cyclic citrullinated peptide antibodies and A1AT may be involved in citrullination and contribute to the development and severity of RA, making them valuable treatment targets requiring further study.

Alpha-1-antitrypsin: A possible host protective factor against Covid-19

Understanding Covid-19 pathophysiology is crucial for a better understanding of the disease and development of more effective treatments. Alpha-1-antitrypsin (A1AT) is a constitutive tissue protector with antiviral and anti-inflammatory properties. A1AT inhibits SARS-CoV-2 infection and two of the most important proteases in the pathophysiology of Covid-19: the transmembrane serine protease 2 (TMPRSS2) and the disintegrin and metalloproteinase 17 (ADAM17). It also inhibits the activity of inflammatory molecules, such as IL-8, TNF-α, and neutrophil elastase (NE). TMPRSS2 is essential for SARS-CoV-2-S protein priming and viral infection. ADAM17 mediates ACE2, IL-6R, and TNF-α shedding. ACE2 is the SARS-CoV-2 entry receptor and a key component for the balance of the renin-angiotensin system, inflammation, vascular permeability, and pulmonary homeostasis. In addition, clinical findings indicate that A1AT levels might be important in defining Covid-19 outcomes, potentially partially explaining associations with air pollution and with diabetes. In this review, we focused on the interplay between A1AT with TMPRSS2, ADAM17 and immune molecules, and the role of A1AT in the pathophysiology of Covid-19, opening new avenues for investigating effective treatments.

IL6 and FAS/FASL gene polymorphisms may be associated with disease progression in HIV-1-positive ethnically mixed patients

The progression of AIDS depends on the complex host and virus interactions. The most important disease progression hallmarks are immune activation and apoptosis. In this study, we address the prevalence of polymorphisms related to proinflammatory and apoptotic genes, such as IFNG (+874T/A), TNF (308G/A), IL6 (-174G/C), IL8 (-251A/T), FAS (-670A/G), and FASL (-124A/G) in 160 ethnically mixed HIV-1-infected patients from multicentre cohorts with different clinical outcomes (13 elite controllers [EC], 66 slow long-term non-progressors [LTNPs], and 81 progressors [P]). The genotyping was accomplished by TaqMan-qPCR. Among all the polymorphisms analyzed in the cytokines, the IL6 -174G/C polymorphism showed a higher frequency of GG genotype in the LTNP and LTNP+EC groups as compared to the P group. Moreover, there was a significantly higher frequency of the G allele in the LTNP and LTNP+EC groups as compared to the P group. On the other hand, the levels of CD4⁺ T lymphocytes were higher among individuals showing the AA and AG genotypes for the FASL -124A/G polymorphism as compared to the GG genotype. Furthermore, the AG and AA genotypes were more frequent, as compared to the GG genotype, in individuals showing a lower viral load. In contrast, for the FAS -670A/G polymorphism, a significantly higher viral load was observed in individuals with the AG genotype as compared to the GG genotype. In conclusion, we found three genetic allelic variants of the IL6 -174G/C, FASL -124A/G, and FAS -670A/G polymorphisms that were related to disease progression and immunological and virological markers in cohorts of HIV-1-positive ethnically mixed patients.

Antagonistic role of IL-1ß and NLRP3/IL-18 genetics in chronic HIV-1 infection

Host genetics affects both susceptibility and progression of HIV-1 infection. NLRP3 inflammasome provides a first-line defense in viral infections, and, accordingly, gain-of-function variants in NLRP3 have been associated with protection against HIV-1. Despite antiretroviral treatment (ART), HIV-infected patients continue to present systemic inflammation with a heterogeneous prognosis. As NLRP3 inflammasome is involved in several chronic diseases by amplifying "sterile" inflammation, its role in chronic phase of HIV infection has been postulated. Little is known about inflammasome genetics in HIV-infected patients and whether it may play a role in the different clinical outcomes. Therefore, we questioned whether NLRP3 inflammasome genetics could affect the clinical course of HIV-1 infection as it does in host/virus interaction. For this purpose, we analyzed selected single nucleotide polymorphisms (SNPs) in ART-treated HIV-infected patients (n = 300), in Long Term Non-Progressors/Elite Controllers and progressors (n = 133), and in HIV-infected individuals submitted to dendritic cell (DC)-based immunotherapy (n = 19). SNPs leading to increased activation of NLRP3 inflammasome are beneficial for patients, while SNPs that negatively affect NLRP3 activation or IL-18 production, detrimental. In contrast, gain-of-function variant in IL1B is also detrimental for patients, suggesting that while IL-1ß possible contributes to immune exhaustion, the axis NLRP3-inflammasome/IL-18 could act positively in chronic infection. Functional assays supported genetic results: NLRP3 variants associated with good quality HIV+ DC, and IL1B -511C > T with a poor one. Loss-of-function SNPs affect HIV+ T cells proliferation. These findings proposed for the first time that NLRP3 inflammasome, mainly through IL-18, play a protective role in chronic HIV infection.

Update on α1-antitrypsin deficiency

α₁-Antitrypsin deficiency (AATD) is an inherited metabolic disorder in which mutations in the coding sequence of the SERPINA1 gene prevent secretion of α₁-antitrypsin (α₁-AT) and cause predisposition to pulmonary and liver diseases. The heterogeneity of clinical manifestations in AATD is related to the complexity of biological function of α₁-AT. The role of smoking is crucial in the natural history of lung damage progression in severe AATD individuals, even if it also partly explains the heterogeneity in lung disease. Lung damage progression in AATD can also be related to body mass index, exacerbation rate, sex, environmental exposure and specific mutations of SERPINA1. Recent randomised controlled trials, together with previous observational work, have provided compelling evidence for the importance of early detection and intervention in order to enable patients to receive appropriate treatment and preserve functional lung tissue.

Early detection and intervention in cases of α₁-antitrypsin deficiency are essential to enable appropriate treatment and preserve functional lung tissuehttp://ow.ly/Mr3P30jUEyn

A1AT polymorphisms may be associated with clinical characteristics of retrovirus infections in a mixed ethnic population from the Brazilian Amazon region

OBJECTIVES

This study investigated the association of alpha-1-antrypsin deficiency (A1AT; S and Z polymorphisms) with HIV-1 and HTLV-1 infection.

METHODS

Blood samples from 201 HIV-1-infected and 115 HTLV-1-infected individuals were examined and compared with those from 300 healthy controls. Genotyping of A1AT (S and Z) and quantification of plasma viral load were performed using RT-PCR, and the CD4+/CD8+ T-cell count was determined by flow cytometry.

RESULTS

The wild-type MM genotype showed the highest frequency in each of the three groups investigated. SS and ZZ homozygous genotypes (variants) were observed only among HTLV-1 patients and controls, respectively. Genotype MS was significantly less frequent in HTLV-1-positive persons than in controls. Statistically significant differences were observed when comparing genotype frequencies between symptomatic and asymptomatic HTLV-1-infected persons. The distribution of plasma HIV-1 viral load among individuals with different genotypes of A1AT polymorphism also differed significantly.

CONCLUSIONS

The results suggest that A1AT polymorphisms may be associated with human retrovirus infections when dealing with an ethnically mixed population from the Amazon region of Brazil.

Alpha-1 Antitrypsin as a Therapeutic Agent for Conditions not Associated with Alpha-1 Antitrypsin Deficiency

Alpha-1 antitrypsin is a positive acute phase reactant whose serum level rises in response to inflammatory stress, presumably to balance pro-inflammatory processes. In addition to its serine protease inhibitory action, alpha-1 antitrypsin exhibits broader anti-inflammatory and immunomodulatory activity, and increasing its serum concentration by the administration of exogenous alpha-1 antitrypsin to above-normal levels potentially could be therapeutic in conditions other than alpha-1 antitrypsin deficiency. In vitro observations, studies in animal models and in some instances early human trials suggest that intravenous or inhaled alpha-1 antitrypsin has beneficial effects in type 1 diabetes, viral infections, graft-versus-host disease, cystic fibrosis, and alpha-1 antitrypsin-replete chronic obstructive pulmonary disease among others. While the results of pivotal clinical trials have not been reported to date, new indications for alpha-1 antitrypsin therapy are likely to emerge in the future based on currently available scientific data.

Acute-phase protein α1-anti-trypsin: diverting injurious innate and adaptive immune responses from non-authentic threats

One would assume that the anti-inflammatory activity of α1-anti-trypsin (AAT) is the result of inhibiting neutrophil enzymes. However, AAT exhibits tolerogenic activities that are difficult to explain by serine-protease inhibition or by reduced inflammatory parameters. Targets outside the serine-protease family have been identified, supporting the notion that elastase inhibition, the only functional factory release criteria for clinical-grade AAT, is over-emphasized. Non-obvious developments in the understanding of AAT biology disqualify it from being a straightforward anti-inflammatory agent: AAT does not block dendritic cell activities, nor does it promote viral and tumour susceptibilities, stunt B lymphocyte responses or render treated patients susceptible to infections; accordingly, outcomes of elevated AAT do not overlap those attained by immunosuppression. Aside from the acute-phase response, AAT rises during the third trimester of pregnancy and also in advanced age. At the molecular level, AAT docks onto cholesterol-rich lipid-rafts and circulating lipid particles, directly binds interleukin (IL)-8, ADAM metallopeptidase domain 17 (ADAM17) and danger-associated molecular pattern (DAMP) molecules, and its activity is lost to smoke, high glucose levels and bacterial proteases, introducing a novel entity - 'relative AAT deficiency'. Unlike immunosuppression, AAT appears to help the immune system to distinguish between desired responses against authentic threats, and unwanted responses fuelled by a positive feedback loop perpetuated by, and at the expense of, inflamed injured innocent bystander cells. With a remarkable clinical safety record, AAT treatment is currently tested in clinical trials for its potential benefit in a variety of categorically distinct pathologies that share at least one common driving force: cell injury.