Autophagy hijacking in PBMC From COVID-19 patients results in lymphopenia

Autophagy is a homeostatic process responsible for the self-digestion of intracellular components and antimicrobial defense by inducing the degradation of pathogens into autophagolysosomes. Recent findings suggest an involvement of this process in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, the role of autophagy in the immunological mechanisms of coronavirus disease 2019 (COVID-19) pathogenesis remains largely unexplored. This study reveals the presence of autophagy defects in peripheral immune cells from COVID-19 patients. The impairment of the autophagy process resulted in a higher percentage of lymphocytes undergoing apoptosis in COVID-19 patients. Moreover, the inverse correlation between autophagy markers levels and peripheral lymphocyte counts in COVID-19 patients confirms how a defect in autophagy might contribute to lymphopenia, causing a reduction in the activation of viral defense. These results provided intriguing data that could help in understanding the cellular underlying mechanisms in COVID-19 infection, especially in severe forms

Autophagy in Rheumatic Diseases: Role in the Pathogenesis and Therapeutic Approaches

Autophagy is a lysosomal pathway for the degradation of damaged proteins and intracellular components that promotes cell survival under specific conditions. Apoptosis is, in contrast, a critical programmed cell death mechanism, and the relationship between these two processes influences cell fate. Recent evidence suggests that autophagy and apoptosis are involved in the self-tolerance promotion and in the regulatory mechanisms contributing to disease susceptibility and immune regulation in rheumatic diseases. The aim of this review is to discuss how the balance between autophagy and apoptosis may be dysregulated in multiple rheumatic diseases and to dissect the role of autophagy in the pathogenesis of rheumatoid arthritis, systemic lupus erythematosus, and Sjögren’s syndrome. Furthermore, to discuss the potential capacity of currently used disease-modifying antirheumatic drugs (DMARDs) to target and modulate autophagic processes

Autophagy in Rheumatic Diseases: Role in the Pathogenesis and Therapeutic Approaches

Autophagy is a lysosomal pathway for the degradation of damaged proteins and intracellular components that promotes cell survival under specific conditions. Apoptosis is, in contrast, a critical programmed cell death mechanism, and the relationship between these two processes influences cell fate. Recent evidence suggests that autophagy and apoptosis are involved in the self-tolerance promotion and in the regulatory mechanisms contributing to disease susceptibility and immune regulation in rheumatic diseases. The aim of this review is to discuss how the balance between autophagy and apoptosis may be dysregulated in multiple rheumatic diseases and to dissect the role of autophagy in the pathogenesis of rheumatoid arthritis, systemic lupus erythematosus, and Sjögren’s syndrome. Furthermore, to discuss the potential capacity of currently used disease-modifying antirheumatic drugs (DMARDs) to target and modulate autophagic processes

Protenuria in SLE:. is it always lupus

Proteinuria is one of the most typical manifestations of kidney involvement in Systemic Lupus Erythematosus (SLE). We report the case of a 23-year-old woman with a 6-year-long history of SLE presenting with proteinuria after a three-year remission on hydroxychloroquine. Kidney histological examination showed alterations inconsistent with lupus nephritis and suggestive of hydroxychloroquine toxicity or Fabry disease. The latter was confirmed by genetic assay

Up-regulation of autophagy by etanercept treatment results in TNF-induced apoptosis reduction in EA.hy926 endothelial cell line

OBJECTIVES: Rheumatoid arthritis (RA) is an autoimmune systemic inflammatory disease associated with a high prevalence of atherosclerosis. Endothelial dysfunction has emerged as a potentially valuable prognostic tool in predicting the development of atherosclerosis. Tumour necrosis factor (TNF) is the main cytokine involved in RA pathogenesis, exerting a pro-atherogenic role. TNF-inhibitors are effective treatments in RA, also improving endothelial function. Regarding this, no experimental data are known about the involvement of etanercept. We investigated the contribution of TNF to endothelial dysfunction and the effect of in vitro treatment with etanercept, with a special focus on autophagy and apoptosis pathways.METHODS: Autophagy and apoptosis were evaluated by Western blot and flow cytometry in EA.hy926 endothelial cells treated with TNF alone or in combination with etanercept for 24h.RESULTS: Blocking autophagy, TNF was able to induce endothelial cell apoptosis. Co-treatment with etanercept reverted this effect, up-regulating the autophagy pathway.CONCLUSIONS: Our results confirm the protective role of etanercept, by restoring autophagy on TNF-induced endothelial damage

Alternative exon usage in TRIM21 determines the antigenicity of Ro52/TRIM21 in systemic lupus erythematosus

The origin and mechanisms of autoantigen generation in systemic lupus erythematosus (SLE) are poorly understood. Here, we identified SLE neutrophils activated in vivo by IFN as a prominent source of Ro52, also known as tripartite motif-containing protein 21 (TRIM21), a critical autoantigen historically thought to be primarily generated by keratinocytes in SLE. Different from mononuclear cells and keratinocytes, SLE neutrophils are enriched in several unique Ro52 species containing a core sequence encoded by exon 4 (Ro52Ex4) in TRIM21. Ro52Ex4 is the main target of anti-Ro52 antibodies and is found in 2 Ro52 variants (Ro52α and an isoform termed Ro52γ) upregulated in SLE neutrophils. Further analysis of Ro52γ revealed a subset of autoantibodies against a unique C-terminal domain (Ro52γCT) generated from a frameshift due to the lack of exon 6 in Ro52γ. Antibodies to Ro52Ex4 and Ro52γCT distinguish SLE patient subsets characterized by distinct clinical, laboratory, treatment, and transcriptional profiles that are not discerned by the "classical"anti-Ro52 antibodies. These studies uncover IFN-activated neutrophils as a key source of unique immunogenic forms of Ro52 in SLE. Moreover, the finding of Ro52Ex4 and Ro52γCT as core targets of anti-Ro52 antibodies focus interest on Ro52γ as the potential isoform toward which immunological tolerance is initially lost in SLE

Homocysteinylated alpha 1 antitrypsin as an antigenic target of autoantibodies in seronegative rheumatoid arthritis patients

Rheumatoid arthritis (RA) is a chronic autoimmune disease and rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA) are the most frequently detected autoantibodies (autoAbs). To date, more than 20% of RA cases are still defined as seronegative forms (seronegative RA, SN-RA). The aim of this study was to identify new antigenic targets of autoAbs in RA patients, which can also be recognized in SN-RA. Using a proteomic approach, we tested sera from SN-RA patients by analyzing synovial fluid (SF) proteins from these patients. Sera from SN-RA patients revealed a strong reactive spot, corresponding to alpha 1 antitrypsin (A1AT). Reverse-phase nanoliquid chromatography and tandem mass spectrometry (Matrix Assisted Laser Desorption/Ionization-Time Of Flight, MALDI-TOF/TOF) confirmed the presence of A1AT in SF and showed that homocysteinylation was one of the post-translational modifications of A1AT. Homocysteinylated (Hcy)-A1AT immunoprecipitated from SN-RA patients' SFs and in vitro modified Hcy-A1AT were used as antigens by Enzyme-Linked ImmunoSorbent Assay (ELISA) to test the presence of specific autoAbs in sera from 111 SN-RA patients, 132 seropositive (SP)-RA patients, and from 95 patients with psoriatic arthritis, 40 patients with osteoarthritis, and 41 healthy subjects as control populations. We observed that a large portion of SN-RA patients (75.7%), and also most of SP-RA patients' sera (87.1%) displayed anti-Hcy-A1AT autoAbs (anti-HATA). Native A1AT was targeted at a lower rate by SP-RA patients autoAbs, while virtually no SN-RA patients' sera showed the presence of anti-native A1AT autoAbs. In conclusion, anti-HATA can be considered potential biomarkers for RA, also in the SN forms. The discovery of novel autoAbs targeting specific autoantigens can represent higher clinic significance for all RA patients' population

Maladaptive Autophagy in the Pathogenesis of Autoimmune Epithelitis in Sjögren's Syndrome

OBJECTIVE: Salivary gland epithelial cells (SGECs) are key cellular drivers in the pathogenesis of primary Sjögren's syndrome (SS); however, the mechanisms sustaining SGEC activation in primary SS remain unclear. We undertook this study to determine the role of autophagy in the survival and activation of SGECs in primary SS.METHODS: Primary SGECs isolated from the minor SGs of patients with primary SS or sicca syndrome were evaluated by flow cytometry, immunoblotting, and immunofluorescence to assess autophagy (autophagic flux, light chain 3 IIB [LC3-IIB], p62, LC3-IIB+/lysosome-associated membrane protein 1 [LAMP-1] staining), apoptosis (annexin V/propidium iodide [PI], caspase 3), and activation (intercellular adhesion molecule, vascular cell adhesion molecule). Focus score and germinal center presence were assessed in the SGs from the same patients to assess correlation with histologic severity. Human SG (HSG) cells were stimulated in vitro with peripheral blood mononuclear cells (PBMCs) and serum from primary SS patients in the presence or absence of autophagy inhibitors to determine changes in autophagy and epithelial cell activation.RESULTS: SGECs from primary SS patients (n = 24) exhibited increased autophagy (autophagic flux [P = 0.001]; LC3-IIB [P = 0.02]; p62 [P = 0.064]; and as indicated by LC3-IIB/LAMP-1+ staining), increased expression of antiapoptotic molecules (Bcl-2 [P = 0.006]), and reduced apoptosis (annexin V/PI [P = 0.002]; caspase 3 [P = 0.057]), compared to samples from patients with sicca syndrome (n = 16). Autophagy correlated with histologic disease severity. In vitro experiments on HSG cells stimulated with serum and PBMCs from primary SS patients confirmed activation of autophagy and expression of adhesion molecules, which was reverted upon pharmacologic inhibition of autophagy.CONCLUSION: In primary SS SGECs, inflammation induces autophagy and prosurvival mechanisms, which promote SGEC activation and mirror histologic severity. These findings indicate that autophagy is a central contributor to the pathogenesis of primary SS and a new therapeutic target.</p

Maladaptive Autophagy in the Pathogenesis of Autoimmune Epithelitis in Sjögren's Syndrome

OBJECTIVE: Salivary gland epithelial cells (SGECs) are key cellular drivers in the pathogenesis of primary Sjögren's syndrome (SS); however, the mechanisms sustaining SGEC activation in primary SS remain unclear. We undertook this study to determine the role of autophagy in the survival and activation of SGECs in primary SS.METHODS: Primary SGECs isolated from the minor SGs of patients with primary SS or sicca syndrome were evaluated by flow cytometry, immunoblotting, and immunofluorescence to assess autophagy (autophagic flux, light chain 3 IIB [LC3-IIB], p62, LC3-IIB+/lysosome-associated membrane protein 1 [LAMP-1] staining), apoptosis (annexin V/propidium iodide [PI], caspase 3), and activation (intercellular adhesion molecule, vascular cell adhesion molecule). Focus score and germinal center presence were assessed in the SGs from the same patients to assess correlation with histologic severity. Human SG (HSG) cells were stimulated in vitro with peripheral blood mononuclear cells (PBMCs) and serum from primary SS patients in the presence or absence of autophagy inhibitors to determine changes in autophagy and epithelial cell activation.RESULTS: SGECs from primary SS patients (n = 24) exhibited increased autophagy (autophagic flux [P = 0.001]; LC3-IIB [P = 0.02]; p62 [P = 0.064]; and as indicated by LC3-IIB/LAMP-1+ staining), increased expression of antiapoptotic molecules (Bcl-2 [P = 0.006]), and reduced apoptosis (annexin V/PI [P = 0.002]; caspase 3 [P = 0.057]), compared to samples from patients with sicca syndrome (n = 16). Autophagy correlated with histologic disease severity. In vitro experiments on HSG cells stimulated with serum and PBMCs from primary SS patients confirmed activation of autophagy and expression of adhesion molecules, which was reverted upon pharmacologic inhibition of autophagy.CONCLUSION: In primary SS SGECs, inflammation induces autophagy and prosurvival mechanisms, which promote SGEC activation and mirror histologic severity. These findings indicate that autophagy is a central contributor to the pathogenesis of primary SS and a new therapeutic target.</p