Defects in the regulatory clearance mechanisms favor the breakdown of self-tolerance during spontaneous autoimmune orchitis

We identified aberrations leading to spontaneous autoimmune orchitis (AIO) in mink, a seasonal breeder and natural model for autoimmunity. This study provides evidence favoring the view that a malfunction of the clearance mechanisms for apoptotic cell debris arising from imbalances in phagocyte receptors or cytokines acting on Sertoli cells constitutes a major factor leading to breakdown of self-tolerance during spontaneous AIO. Serum anti-sperm antibody titers measured by ELISA reflected spermatogenic activity without causing immune inflammatory responses. Orchitic mink showed excess antibody production accompanied by spermatogenic arrest, testicular leukocyte infiltration, and infertility. AIO serum labeled the postacrosomal region, the mid and end piece of mink sperm, whereas normal mink serum did not. Normal serum labeled plasma membranes, whereas AIO serum reacted with germ cell nuclei. Western blot analyses revealed that AIO serum reacted specifically to a 23- and 50-kDa protein. The number of apostain-labeled apoptotic cells was significantly higher in orchitic compared with normal tubules. However, apoptosis levels measured by ELISA in seminiferous tubular fractions (STf) were not significantly different in normal and orchitic tubules. The levels of CD36, TNF-α, TNF-α RI, IL-6, and Fas but not Fas-ligand (L), and ATP-binding cassette transporter ABCA1 were changed in AIO STf. TNF-α and IL-6 serum levels were increased during AIO. Fas localized to germ cells, Sertoli cells, and the lamina propria of the tubules and Fas-L, to germ cells. Fas colocalized with Fas-L in residual bodies in normal testis and in giant cells and infiltrating leukocytes in orchitic tubules.

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The Immunoprotective Effect of Sertoli Cells Coencapsulated with Islet Xenografts is Not Dependent upon Fas Ligand Expression

Cell Transplantation ◽

10.3727/000000002783985288 ◽

2002 ◽

Vol 11 (8) ◽

pp. 799-801 ◽

Cited By ~ 18

Author(s):

Hua Yang ◽

Ayman Al-Jazaeri ◽

James R. Wright

Keyword(s):

Graft Survival ◽

Sertoli Cells ◽

Fas Ligand ◽

Testicular Cell ◽

Group Iii ◽

Group I ◽

Significant Difference ◽

Group Ii ◽

Fas L ◽

Cell Fractions

Coencapsulation with Sertoli-enriched testicular cell fractions prolongs islet graft survival time compared with islet encapsulation alone in a highly discordant tilapia (fish)-to-mouse xenotransplantation model. Here we investigate whether Fas ligand (Fas-L) expression by testicular Sertoli cells is responsible for this additional protective effect. Sertoli-enriched testicular cell fractions (7 × 106 cells) harvested from either Fas-L-defective (group I) or Fas-L-positive (group II) mice were coencapsulated in alginate gel spheres with fish islets and then transplanted into streptozotocin-diabetic Balb/c recipients. Group III mice received encapsulated islets without coencapsulated Sertoli cells. After transplantation, blood glucose levels were monitored three times per week. Mean graft survival times for the three groups were: group I = 35.6 ± 10.2 days (n = 9), group II = 31.3 ± 9.4 days (n = 7), and group III = 23.3 ± 2.2 days (n = 6) (ANOVA, p = 0.043). Coencapsulation, regardless of the Fas-L status of the Sertoli cell donors, modestly prolonged graft survival. There was no significant difference between Fas-L-deficient and Fas-L-positive donors. Our results suggest that Fas/Fas-L interaction is not responsible for the additional protection afforded to encapsulated discordant islet xenografts by coencapsulation with Sertoli cells.

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Apoptosis in Acute Shigellosis Is Associated with Increased Production of Fas/Fas Ligand, Perforin, Caspase-1, and Caspase-3 but Reduced Production of Bcl-2 and Interleukin-2

Infection and Immunity ◽

10.1128/iai.70.6.3199-3207.2002 ◽

2002 ◽

Vol 70 (6) ◽

pp. 3199-3207 ◽

Cited By ~ 42

Author(s):

Rubhana Raqib ◽

Caroline Ekberg ◽

Protim Sharkar ◽

Pradip K. Bardhan ◽

Arturo Zychlinsky ◽

...

Keyword(s):

Cell Death ◽

Caspase 3 ◽

Fas Ligand ◽

Apoptotic Cell ◽

Interleukin 2 ◽

Acute Stage ◽

Shigella Dysenteriae ◽

Caspase 1 ◽

Fas L

ABSTRACT Shigella dysenteriae type 1-induced apoptotic cell death in rectal tissues from patients infected with Shigella dysenteriae type 1 was studied by the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) technique and annexin V staining. Expression of proteins and cytokines participating in the apoptotic process (caspase-1, caspase-3, Fas [CD95], Fas ligand [Fas-L], perforin, granzyme A, Bax, WAF-1, Bcl-2, interleukin-2 [IL-2], IL-18, and granulocyte-macrophage colony-stimulating factor) in tissue in the acute and convalescent stages of dysentery was quantified at the single-cell level by in situ immunostaining. Apoptotic cell death in the lamina propria was markedly up-regulated at the acute stage (P < 0.05), where an increased number of necrotic cells were also seen. Phenotypic analysis of apoptotic cells revealed that 43% of T cells (CD3), 10% of granulocytes (CD15), and 5% of macrophages (CD56) underwent apoptosis. Increased activity of caspase-1 persisted in the rectum up to 1 month after onset. More-extensive expression of Fas, Fas-L, perforin, caspase-3, and IL-18, but not IL-2, at the acute stage than at the convalescent stage was observed. Increased expression of caspase-3 and IL-18 in tissues with severe inflammation compared to expression in those with mild inflammation was evident, implying a possible role in the perpetuation of inflammation. Significantly reduced cell death during convalescence was associated with a significant up-regulation of Bcl-2, Bax, and WAF-1 expression in the rectum compared to that in the acute phase of infection. Thus, induction of apoptosis at the local site in the early phase of S. dysenteriae type 1 infection was associated with a significant up-regulation of Fas/Fas-L and perforin and granzyme A expression and a down-regulation of Bcl-2 and IL-2, which promote cell survival.

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Peripheral T cells undergoing superantigen-induced apoptosis in vivo express B220 and upregulate Fas and Fas ligand.

Journal of Experimental Medicine ◽

10.1084/jem.183.2.431 ◽

1996 ◽

Vol 183 (2) ◽

pp. 431-437 ◽

Cited By ~ 93

Author(s):

T Renno ◽

M Hahne ◽

J Tschopp ◽

H R MacDonald

Keyword(s):

T Cells ◽

Fas Ligand ◽

Apoptotic Cell ◽

Initial Increase ◽

Apoptotic Cells ◽

Peripheral T Cells ◽

Fas L ◽

Induced Apoptosis

Staphylococcal enterotoxin B (SEB) is a bacterial superantigen (SAg) that predominantly interacts with V(beta)8+ T cells. In vivo treatment of mice with SEB leads to an initial increase in the percentage of V(beta)8+ T cells, followed by a decrease in the numbers of these cells, eventually reaching lower levels than those found before treatment with the SAg. This decrease is due to apoptosis of the SEB-responding cells. In the present study, we use the distinct light scattering characteristics of apoptotic cells to characterize T cells that are being deleted in response to SEB in vivo. We show that dying, SEB-reactive T cells express high levels of Fas and Fas ligand (Fas-L), which are implicated in apoptotic cell death. In addition, the B cell marker B220 is upregulated on apoptotic cells. Moreover, we show that the generation of cells with an apoptotic phenotype is severely impaired in response to SEB in functional Fas-L-deficient mutant gld mice, confirming the role of the Fas pathway in SAg mediated peripheral deletion in vivo.

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SARS-CoV-2 Infection of Microglia Elicits Pro-inflammatory Activation and Apoptotic Cell Death

10.1101/2022.01.04.475015 ◽

2022 ◽

Author(s):

Gi Uk Jeong ◽

Jaemyun Lyu ◽

Kyun-Do Kim ◽

Young Cheul Chung ◽

Gun Young Yoon ◽

...

Keyword(s):

Cell Death ◽

Inflammatory Responses ◽

Apoptotic Cell ◽

Neurological Diseases ◽

Late Phase ◽

Death Receptor ◽

Human Microglia ◽

Tnf Α ◽

Inflammatory Activation ◽

Factor Α

Accumulating evidence suggests that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes various neurological symptoms in coronavirus disease 2019 (COVID-19) patients. The most dominant immune cells in the brain are microglia. Yet, the relationship between neurological manifestations, neuroinflammation, and host immune response of microglia to SARS-CoV-2 has not been well characterized. Here, we report that SARS-CoV-2 can directly infect human microglia, eliciting M1-like pro-inflammatory responses, followed by cytopathic effects. Specifically, SARS-CoV-2 infected human microglial clone 3 (HMC3), leading to inflammatory activation and cell death. RNA-seq analysis also revealed that ER stress and immune responses were induced in the early and apoptotic processes in the late phase of viral infection. SARS-CoV-2-infected HMC3 showed the M1 phenotype and produced pro-inflammatory cytokines such as interleukin (IL)-1β, IL-6, and tumour necrosis factor α (TNF-α), but not the anti-inflammatory cytokine IL-10. After this pro-inflammatory activation, SARS-CoV-2 infection promoted both intrinsic and extrinsic death receptor-mediated apoptosis in HMC3. Using K18-hACE2 transgenic mice, murine microglia were also infected by intranasal inoculation of SARS-CoV-2. This infection induced the acute production of pro-inflammatory microglial IL- 6 and TNF-α and provoked a chronic loss of microglia. Our findings suggest that microglia are potential mediators of SARS-CoV-2-induced neurological problems and, consequently, can be targets of therapeutic strategies against neurological diseases in COVID-19 patients.

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Freeze-etch observations on the tight junctions of sertoli cells grown in organ culture with FSH

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010008256x ◽

1978 ◽

Vol 36 (2) ◽

pp. 340-341

Author(s):

Rita Meyer ◽

Zoltan Posalaky ◽

Dennis Mcginley

Keyword(s):

Organ Culture ◽

Tight Junctions ◽

Sertoli Cell ◽

Germ Cells ◽

Sertoli Cells ◽

Barrier Function ◽

Cell Junction ◽

Intramembranous Particles ◽

Junctional Complexes ◽

Oriented Parallel

The Sertoli cell tight junctional complexes have been shown to be the most important structural counterpart of the physiological blood-testis barrier. In freeze etch replicas they consist of extensive rows of intramembranous particles which are not only oriented parallel to one another, but to the myoid layer as well. Thus the occluding complex has both an internal and an overall orientation. However, this overall orientation to the myoid layer does not seem to be necessary to its barrier function. The 20 day old rat has extensive parallel tight junctions which are not oriented with respect to the myoid layer, and yet they are inpenetrable by lanthanum. The mechanism(s) for the control of Sertoli cell junction development and orientation has not been established, although such factors as the presence or absence of germ cells, and/or hormones, especially FSH have been implicated.

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Anti-β2 Glycoprotein I Antibodies Cause Inflammation and Recruit Dendritic Cells in Platelet Clearance

Thrombosis and Haemostasis ◽

10.1055/s-0037-1616059 ◽

2001 ◽

Vol 86 (11) ◽

pp. 1257-1263 ◽

Cited By ~ 6

Author(s):

Attilio Bondanza ◽

Angelo Manfredi ◽

Valérie Zimmermann ◽

Matteo Iannacone ◽

Angela Tincani ◽

...

Keyword(s):

Dendritic Cells ◽

Inflammatory Responses ◽

Glycoprotein I ◽

Activated Platelets ◽

Tnf Α ◽

Per Se ◽

Antigen Presenting ◽

Antiinflammatory Cytokine

SummaryScavenger phagocytes are mostly responsible for the in vivo clearance of activated or senescent platelets. In contrast to other particulate substrates, the phagocytosis of platelets does not incite pro-inflammatory responses in vivo. This study assessed the contribution of macrophages and dendritic cells (DCs) to the clearance of activated platelets. Furthermore, we verified whether antibodies against the β2 Glycoprotein I (β2GPI), which bind to activated platelets, influence the phenomenon. DCs did not per se internalise activated platelets. In contrast, macrophages efficiently phagocytosed platelets. In agreement with the uneventful nature of the clearance of platelets in vivo, phagocytosing macrophages did not release IL-1β, TNF-α or IL-10. β2GPI bound to activated platelets and was required for their recognition by anti-ββ2GPI antibodies. DCs internalised platelets opsonised by anti-ββ2GPI antibodies. The phagocytosis of opsonised platelets determined the release of TNF-α and IL-1β by DCs and macrophages. Phagocytosing macrophages, but not DCs, secreted the antiinflammatory cytokine IL-1β0. We conclude that anti-ββ2GPI antibodies cause inflammation during platelet clearance and shuttle platelet antigens to antigen presenting DCs.

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Maintenance of self-tolerance by apoptotic cell clearance

Frontiers in Bioscience ◽

10.2741/3135 ◽

2008 ◽

Vol Volume (13) ◽

pp. 6043 ◽

Cited By ~ 1

Author(s):

Masato Tanaka

Keyword(s):

Apoptotic Cell ◽

Apoptotic Cell Clearance ◽

Cell Clearance ◽

Self Tolerance

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Punicalagin Prevents Inflammation in LPS-Induced RAW264.7 Macrophages by Inhibiting FoxO3a/Autophagy Signaling Pathway

Nutrients ◽

10.3390/nu11112794 ◽

2019 ◽

Vol 11 (11) ◽

pp. 2794 ◽

Cited By ~ 8

Author(s):

Cao ◽

Chen ◽

Ren ◽

Zhang ◽

Tan ◽

...

Keyword(s):

Western Blot ◽

Signaling Pathway ◽

Inflammatory Cytokines ◽

Blot Analysis ◽

Western Blot Analysis ◽

Inflammatory Responses ◽

Raw264.7 Macrophages ◽

Tnf Α ◽

Autophagy Inhibition ◽

Pro Inflammatory Cytokines

Punicalagin, a hydrolysable tannin of pomegranate juice, exhibits multiple biological effects, including inhibiting production of pro-inflammatory cytokines in macrophages. Autophagy, an intracellular self-digestion process, has been recently shown to regulate inflammatory responses. In this study, we investigated the anti-inflammatory potential of punicalagin in lipopolysaccharide (LPS) induced RAW264.7 macrophages and uncovered the underlying mechanisms. Punicalagin significantly attenuated, in a concentration-dependent manner, LPS-induced release of NO and decreased pro-inflammatory cytokines TNF-α and IL-6 release at the highest concentration. We found that punicalagin inhibited NF-κB and MAPK activation in LPS-induced RAW264.7 macrophages. Western blot analysis revealed that punicalagin pre-treatment enhanced LC3II, p62 expression, and decreased Beclin1 expression in LPS-induced macrophages. MDC assays were used to determine the autophagic process and the results worked in concert with Western blot analysis. In addition, our observations indicated that LPS-induced releases of NO, TNF-α, and IL-6 were attenuated by treatment with autophagy inhibitor chloroquine, suggesting that autophagy inhibition participated in anti-inflammatory effect. We also found that punicalagin downregulated FoxO3a expression, resulting in autophagy inhibition. Overall these results suggested that punicalagin played an important role in the attenuation of LPS-induced inflammatory responses in RAW264.7 macrophages and that the mechanisms involved downregulation of the FoxO3a/autophagy signaling pathway.

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