scholarly journals mGBP2 engages Galectin-9 and Cytoskeleton-associated Protein 4 for immunity against Toxoplasma gondii

2021 ◽  
Author(s):  
Elisabeth Kravets ◽  
Gereon Poschmann ◽  
Sebastian Haensch ◽  
Stefanie Weidtkamp-Peters ◽  
Daniel Degrandi ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Host Defense ◽  
Defense Mechanisms ◽  
Defense Mechanism ◽  
Parasitophorous Vacuole ◽  
Growth Control ◽  
Protozoan Parasite ◽  
Immune Control ◽  
Interaction Partners ◽  
Host Defense Mechanism

Guanylate binding proteins (GBPs) are large interferon-inducible GTPases, executing essential host defense activities against Toxoplasma gondii, an invasive intracellular apicomplexan protozoan parasite of global importance. T. gondii establishes a parasitophorous vacuole (PV) which shields the parasite from the host's intracellular defense mechanisms. Murine GBPs (mGBPs) recognize T. gondii PVs and assemble into supramolecular mGBP homo- and heterocomplexes that are required for the disruption of the membrane of PVs eventually resulting in the cell-autonomous immune control of vacuole-resident pathogens. We have previously shown that mGBP2 plays an important role in T. gondii immune control. Here, in order to unravel mGBP2 functions, we report Galectin-9 (Gal9) and cytoskeleton-associated protein 4 (Ckap4) as critical mGBP2 interaction partners engaged for immunity to T. gondii. Interestingly, Gal9 and Ckap4 also accumulate and colocalize with mGBP2 at the T. gondii PV. Furthermore, we could prove the requirement of Gal9 and Ckap4 for growth control of T. gondii by CRISPR/Cas9 mediated gene editing. These discoveries clearly indicate that mGBP2 engages Gal9 and Ckap4 and that Gal9 and Ckap4 are critical factors for the mGBP2 coordinated cell autonomous host defense mechanism against T. gondii.

scholarly journals Involvement of Host Defense Mechanisms against Toxoplasma gondii Infection in Anhedonic and Despair-Like Behaviors in Mice

2017 ◽  
Vol 85 (4) ◽  
Author(s):  
Motamed Elsayed Mahmoud ◽  
Ragab Fereig ◽  
Yoshifumi Nishikawa
Keyword(s):  
Toxoplasma Gondii ◽  
Host Defense ◽  
Defense Mechanisms ◽  
Defense Mechanism ◽  
Acute Infection ◽  
Sickness Behavior ◽  
Wild Type ◽  
Chronic Infections ◽  
Content Type ◽  
Ifn Γ

ABSTRACT Toxoplasma gondii is a pathogen relevant to psychiatric disorders. We recently showed that reactivation of chronic T. gondii infection induced depression-like behaviors in mice. Furthermore, it has been hypothesized that depression-like behaviors are mediated via a host defense mechanism against invading pathogens; proximate mechanisms of this behavioral hypothesis remain unclear. In the present study, we investigate the contribution of indoleamine 2,3-dioxygenase (IDO), inflammation, and interferon gamma (IFN-γ) to anhedonic and despair-related behaviors in T. gondii-infected mice by using sucrose preference and forced-swim tests, respectively. First, we confirmed that BALB/c mice exhibited both sickness and depression-like behaviors during acute infection. Treatment of infected wild-type mice with minocycline (anti-inflammatory drug) abated sickness and anhedonic and despair-like behaviors, whereas in T. gondii-infected mice, treatment normalized kynurenine/tryptophan (Kyn/Trp) ratios in both plasma and brain tissue. Additionally, T. gondii infection failed to induce anhedonic and despair-like behaviors or increase the Kyn/Trp ratio in immunocompromised (IFN-γ−/−) mice, whereas sickness behavior was observed in both immunocompetent and IFN-γ−/− mice following infection. Furthermore, treatment with 1-methyl tryptophan (an IDO inhibitor) did not affect locomotor activity, attenuated clinical scores and anhedonic and despair-like behaviors, and resulted in normal Kyn/Trp ratios in T. gondii-infected wild-type mice. Although low levels of serotonin and dopamine were observed in the brain during acute and chronic infections, anhedonic and despair-like behaviors were not detected in the chronic stage of infection. Collectively, our results demonstrated that immune enhancement in response to infection with T. gondii resulted in IFN-γ production, IDO activation, and inflammation associated with anhedonic and despair-like behaviors.

scholarly journals The IL-33-ILC2 pathway protects from amebic colitis

2021 ◽  
Author(s):  
Md Jashim Uddin ◽  
Jhansi L. Leslie ◽  
Stacey L. Burgess ◽  
Noah Oakland ◽  
Brandon Thompson ◽  
...  
Keyword(s):  
Tissue Damage ◽  
Cell Injury ◽  
Defense Mechanism ◽  
Protozoan Parasite ◽  
Lymphoid Cells ◽  
Amebic Colitis ◽  
Host Defense Mechanism ◽  
Important Host ◽  
Murine Colon

AbstractEntamoeba histolytica is a pathogenic protozoan parasite that causes intestinal colitis, diarrhea, and in some cases, liver abscess. Through transcriptomics analysis, we observed that E. histolytica infection was associated with increased expression of IL-33 mRNA in both the human and murine colon. IL-33, the IL-1 family cytokine, is released after cell injury to alert the immune system of tissue damage. Treatment with recombinant IL-33 protected mice from amebic infection and intestinal tissue damage; moreover, blocking IL-33 signaling made mice more susceptible to amebiasis. IL-33 limited the recruitment of inflammatory immune cells and decreased the pro-inflammatory cytokine IL-6 in the cecum. Type 2 immune responses were upregulated by IL-33 treatment during amebic infection. Interestingly, administration of IL-33 protected RAG2–/– mice but not RAG2−/−γc−/− mice, demonstrating that IL-33-mediated protection required the presence of innate lymphoid cells (ILCs). IL-33 induced recruitment of ILC2 but not ILC1 and ILC3 in RAG2−/− mice. At baseline and after amebic infection, there was a significantly higher IL13+ILC2s in C57BL/J mice, which are naturally resistant to amebiasis, than CBA/J mice. Adoptive transfer of ILC2s to RAG2−/−γc−/− mice restored IL-33-mediated protection. These data reveal that the IL-33-ILC2 pathway is an important host defense mechanism against amebic colitis.

scholarly journals Human Serum Albumin Is an Essential Component of the Host Defense Mechanism Against Clostridium difficile Intoxication

2018 ◽  
Vol 218 (9) ◽  
pp. 1424-1435 ◽  
Author(s):  
Alessandra di Masi ◽  
Loris Leboffe ◽  
Fabio Polticelli ◽  
Federica Tonon ◽  
Cristina Zennaro ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Host Defense ◽  
Defense Mechanism ◽  
Essential Component ◽  
Host Defense Mechanism

Association of host cell endoplasmic reticulum and mitochondria with the Toxoplasma gondii parasitophorous vacuole membrane: a high affinity interaction

1997 ◽  
Vol 110 (17) ◽  
pp. 2117-2128 ◽  
Author(s):  
A.P. Sinai ◽  
P. Webster ◽  
K.A. Joiner
Keyword(s):  
Endoplasmic Reticulum ◽  
Toxoplasma Gondii ◽  
Host Cell ◽  
Parasitophorous Vacuole ◽  
Protozoan Parasite ◽  
Host Cells ◽  
Parasitophorous Vacuole Membrane ◽  
Vacuole Membrane ◽  
Protein Protein Interaction ◽  
High Affinity

The parasitophorous vacuole membrane (PVM) of the obligate intracellular protozoan parasite Toxoplasma gondii forms tight associations with host mitochondria and the endoplasmic reticulum (ER). We have used a combination of morphometric and biochemical approaches to characterize this unique phenomenon, which we term PVM-organelle association. The PVM is separated from associated mitochondria and ER by a mean distance of 12 and 18 nm, respectively. The establishment of PVM-organelle association is dependent on active parasite entry, but does not require parasite viability for its maintenance. Association is not a consequence of spatial constraints imposed on the growing vacuole. Morphometric analysis indicates that the extent of mitochondrial association with the PVM stays constant as the vacuole enlarges, whereas the extent of ER association decreases. Disruption of host cell microtubules partially blocks the establishment but not the maintenance of PVM-mitochondrial association, and has no significant effect on PVM-ER association. PVM-organelle association is maintained following disruption of infected host cells, as assessed by electron microscopy and by sub-cellular fractionation showing co-migration of fixed PVM and organelle markers. Taken together, the data suggest that a high affinity, potentially protein-protein interaction between parasite and organelle components is responsible for PVM-organelle association.

scholarly journals Autophagy-activating strategies to promote innate defense against mycobacteria

2019 ◽  
Vol 51 (12) ◽  
pp. 1-10 ◽  
Author(s):  
Yi Sak Kim ◽  
Prashanta Silwal ◽  
Soo Yeon Kim ◽  
Tamotsu Yoshimori ◽  
Eun-Kyeong Jo
Keyword(s):  
Host Defense ◽  
Defense Mechanism ◽  
Multidrug Resistant ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Innate Defense ◽  
Host Defense Mechanism ◽  
A Cell

AbstractMycobacterium tuberculosis (Mtb) is a major causal pathogen of human tuberculosis (TB), which is a serious health burden worldwide. The demand for the development of an innovative therapeutic strategy to treat TB is high due to drug-resistant forms of TB. Autophagy is a cell-autonomous host defense mechanism by which intracytoplasmic cargos can be delivered and then destroyed in lysosomes. Previous studies have reported that autophagy-activating agents and small molecules may be beneficial in restricting intracellular Mtb infection, even with multidrug-resistant Mtb strains. Recent studies have revealed the essential roles of host nuclear receptors (NRs) in the activation of the host defense through antibacterial autophagy against Mtb infection. In particular, we discuss the function of estrogen-related receptor (ERR) α and peroxisome proliferator-activated receptor (PPAR) α in autophagy regulation to improve host defenses against Mtb infection. Despite promising findings relating to the antitubercular effects of various agents, our understanding of the molecular mechanism by which autophagy-activating agents suppress intracellular Mtb in vitro and in vivo is lacking. An improved understanding of the antibacterial autophagic mechanisms in the innate host defense will eventually lead to the development of new therapeutic strategies for human TB.

Pathogenesis of thrombosis

Hematology ◽  
2009 ◽  
Vol 2009 (1) ◽  
pp. 255-258 ◽  
Author(s):  
Bruce Furie
Keyword(s):  
High Pressure ◽  
Host Defense ◽  
Intravital Microscopy ◽  
Defense Mechanism ◽  
Tissue Injury ◽  
Thrombus Formation ◽  
Animal Experiments ◽  
Circulatory System ◽  
Live Animal ◽  
Host Defense Mechanism

Abstract The hemostatic process is a host defense mechanism to preserve the integrity of the closed high pressure circulatory system. This process must remain inactive but poised to minimize extravasation of blood from the vasculature following tissue injury. Given the complexity of the hemostatic mechanism, paradigms developed from biochemical and cell biological approaches have been revisited by studying thrombus formation in a live animal by intravital microscopy. Many of these paradigms have proven accurate, but others need to be reconsidered given the results of whole animal experiments.

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