Inflammasomes: Intracellular mediators of immune defense

2019 ◽  
Vol 670 ◽  
pp. 1-3
Author(s):  
Justin A. MacDonald
2019 ◽  
Vol 21 (1) ◽  
pp. 7-19 ◽  

Multifaceted evidence supports the hypothesis that inflammatory-immune mechanisms contribute to Alzheimer disease (AD) neuropathology and genetic association of several immune specific genes (TREM2, CR1, and CD33) suggests that maladaptive immune responses may be pivotal drivers of AD pathogenesis. We reviewed microglia-related data from postmortem AD studies and examined supporting evidence from AD animal models to answer the following questions: i) What is the temporal sequence of immune activation in AD progression and what is its impact on cognition? ii) Are there discordant, "primed", microglia responses in AD vs successful cognitive aging? iii) Does central nervous system (CNS) repair in aging depend on recruitment of the elements of cellular adaptive immune response such as effector T cells, and can the recruitment of systemic immune cells ameliorate AD neuropathology? iv) How effective are the immune-system-based therapeutic approaches currently employed for the treatment of AD?


2020 ◽  
Vol 20 (9) ◽  
pp. 770-781 ◽  
Author(s):  
Poornima Sharma ◽  
Anjali Sharma ◽  
Faizana Fayaz ◽  
Sharad Wakode ◽  
Faheem H. Pottoo

Alzheimer’s disease (AD) is the most prevalent and severe neurodegenerative disease affecting more than 0.024 billion people globally, more common in women as compared to men. Senile plaques and amyloid deposition are among the main causes of AD. Amyloid deposition is considered as a central event which induces the link between the production of β amyloid and vascular changes. Presence of numerous biomarkers such as cerebral amyloid angiopathy, microvascular changes, senile plaques, changes in white matter, granulovascular degeneration specifies the manifestation of AD while an aggregation of tau protein is considered as a primary marker of AD. Likewise, microvascular changes, activation of microglia (immune defense system of CNS), amyloid-beta aggregation, senile plaque and many more biomarkers are nearly found in all Alzheimer’s patients. It was seen that 70% of Alzheimer’s cases occur due to genetic factors. It has been reported in various studies that apolipoprotein E(APOE) mainly APOE4 is one of the major risk factors for the later onset of AD. Several pathological changes also occur in the white matter which include dilation of the perivascular space, loss of axons, reactive astrocytosis, oligodendrocytes and failure to drain interstitial fluid. In this review, we aim to highlight the various biological signatures associated with the AD which may further help in discovering multitargeting drug therapy.


2001 ◽  
Vol 158 (2) ◽  
pp. 136
Author(s):  
Møller ◽  
Merino ◽  
Brown ◽  
Robertson

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nathaniel B. Bone ◽  
Eugene J. Becker ◽  
Maroof Husain ◽  
Shaoning Jiang ◽  
Anna A. Zmijewska ◽  
...  

AbstractMetabolic and bioenergetic plasticity of immune cells is essential for optimal responses to bacterial infections. AMPK and Parkin ubiquitin ligase are known to regulate mitochondrial quality control mitophagy that prevents unwanted inflammatory responses. However, it is not known if this evolutionarily conserved mechanism has been coopted by the host immune defense to eradicate bacterial pathogens and influence post-sepsis immunosuppression. Parkin, AMPK levels, and the effects of AMPK activators were investigated in human leukocytes from sepsis survivors as well as wild type and Park2−/− murine macrophages. In vivo, the impact of AMPK and Parkin was determined in mice subjected to polymicrobial intra-abdominal sepsis and secondary lung bacterial infections. Mice were treated with metformin during established immunosuppression. We showed that bacteria and mitochondria share mechanisms of autophagic killing/clearance triggered by sentinel events that involve depolarization of mitochondria and recruitment of Parkin in macrophages. Parkin-deficient mice/macrophages fail to form phagolysosomes and kill bacteria. This impairment of host defense is seen in the context of sepsis-induced immunosuppression with decreased levels of Parkin. AMPK activators, including metformin, stimulate Parkin-independent autophagy and bacterial killing in leukocytes from post-shock patients and in lungs of sepsis-immunosuppressed mice. Our results support a dual role of Parkin and AMPK in the clearance of dysfunctional mitochondria and killing of pathogenic bacteria, and explain the immunosuppressive phenotype associated Parkin and AMPK deficiency. AMPK activation appeared to be a crucial therapeutic target for the macrophage immunosuppressive phenotype and to reduce severity of secondary bacterial lung infections and respiratory failure.


Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 330
Author(s):  
Hai Huang ◽  
Juan Du ◽  
Shang-Wei Li ◽  
Tao Gong

Coridius chinensis is a valuable medicinal insect resource in China. Previous studies have indicated that the antibacterial and anticancer effects of the C. chinensis extract mainly come from the active polypeptides. Lysozyme is an effective immune effector in insect innate immunity and usually has excellent bactericidal effects. There are two kinds of lysozymes in insects, c-type and i-type, which play an important role in innate immunity and intestinal digestion. Studying lysozyme in C. chinensis will be helpful to further explore the evolutionary relationship and functional differences among lysozymes of various species and to determine whether they have biological activity and medicinal value. In this study, a lysozyme CcLys2 was identified from C. chinensis. CcLys2 contains 223 amino acid residues, and possesses a typical domain of the c-type lysozyme and a putative catalytic site formed by two conserved residues Glu32 and Asp50. Phylogenetic analysis showed that CcLys2 belongs to the H-branch of the c-type lysozyme. The analysis of spatiotemporal expression patterns indicated that CcLys2 was mainly expressed in the fat body of C. chinensis adults and was highly expressed in the second- and fifth-instar nymphs. In addition, CcLys2 was significantly up-regulated after injecting and feeding bacteria. In the bacterial inhibition assay, it was found that CcLys2 had antibacterial activity against Gram-positive bacteria at a low pH. These results indicate that CcLys2 has muramidase activity, involves in the innate immunity of C. chinensis, and is also closely related to the bacterial immune defense or digestive function of the intestine.


2021 ◽  
Vol 11 (12) ◽  
pp. 5496
Author(s):  
Zarina Amin ◽  
Nur Ariffah Waly ◽  
Sazmal Effendi Arshad

A challenging problem in the aquaculture industry is bacterial disease outbreaks, which result in the global reduction in fish supply and foodborne outbreaks. Biofilms in marine pathogens protect against antimicrobial treatment and host immune defense. Zeolites are minerals of volcanic origin made from crystalline aluminosilicates, which are useful in agriculture and in environmental management. In this study, silver-ion-exchanged zeolite A of four concentrations; 0.25 M (AgZ1), 0.50 M (AgZ2), 1.00 M (AgZ3) and 1.50 M (AgZ4) were investigated for biofilm inhibition and antimicrobial properties against two predominant marine pathogens, V. campbelli and V. parahemolyticus, by employing the minimum inhibitory concentration (MIC) and crystal violet biofilm quantification assays as well as scanning electron microscopy. In the first instance, all zeolite samples AgZ1–AgZ4 showed antimicrobial activity for both pathogens. For V. campbellii, AgZ4 exhibited the highest MIC at 125.00 µg/mL, while for V. parahaemolyticus, the highest MIC was observed for AgZ3 at 62.50 µg/mL. At sublethal concentration, biofilm inhibition of V. campbelli and V. parahemolyticus by AgZ4 was observed at 60.2 and 77.3% inhibition, respectively. Scanning electron microscopy exhibited profound structural alteration of the biofilm matrix by AgZ4. This is the first known study that highlights the potential application of ion-exchanged zeolite A against marine pathogens and their biofilms.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hong Li ◽  
Xiang Ma ◽  
Yanqiong Tang ◽  
Dan Wang ◽  
Ziding Zhang ◽  
...  

Abstract Background Aeromonas veronii is a bacterial pathogen in aquaculture, which produces virulence factors to enable it colonize and evade host immune defense. Given that experimental verification of virulence factors is time-consuming and laborious, few virulence factors have been characterized. Moreover, most studies have only focused on single virulence factors, resulting in biased interpretation of the pathogenesis of A. veronii. Results In this study, a PPI network at genome-wide scale for A. veronii was first constructed followed by prediction and mapping of virulence factors on the network. When topological characteristics were analyzed, the virulence factors had higher degree and betweenness centrality than other proteins in the network. In particular, the virulence factors tended to interact with each other and were enriched in two network modules. One of the modules mainly consisted of histidine kinases, response regulators, diguanylate cyclases and phosphodiesterases, which play important roles in two-component regulatory systems and the synthesis and degradation of cyclic-diGMP. Construction of the interspecies PPI network between A. veronii and its host Oreochromis niloticus revealed that the virulence factors interacted with homologous proteins in the host. Finally, the structures and interacting sites of the virulence factors during interaction with host proteins were predicted. Conclusions The findings here indicate that the virulence factors probably regulate the virulence of A. veronii by involving in signal transduction pathway and manipulate host biological processes by mimicking and binding competitively to host proteins. Our results give more insight into the pathogenesis of A. veronii and provides important information for designing targeted antibacterial drugs.


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