Search Results (84)

Pediatric hydrocephalus results from the overproduction, obstruction, or inability to resorb cerebrospinal fluid (CSF), which may lead to ventricular enlargement. Hydrocephalus may be secondary to other pathologies, including intraventricular hemorrhage (IVH). Surgical intervention may include a ventricular access device or a ventriculosubgaleal shunt in premature infants who are too small for permanent CSF diversion. Hydrocephalus, an inflammatory pathology, involves activation of the inflammasome. Elevation in pro-inflammatory proteins is often associated with worsening clinical outcomes in pediatric pathologies. Whether inflammasome proteins are reliable biomarkers for pediatric hydrocephalus has not been established. We analyzed CSF samples via an ELLA assay from pediatric hydrocephalic patients with IVH of prematurity vs. controls and compared changes in inflammasome protein concentrations post-reservoir surgery at different time points. The area under the curve was calculated using receiver operator characteristic curves. The levels of apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), caspase-1, and interleukin-18 were significantly elevated in pediatric hydrocephalic patients with IVH vs. controls. Thus, these proteins are reliable biomarkers of the inflammatory response in pediatric hydrocephalus following ROC analysis, with an AUC of 1.0 and high sensitivity and specificity at the corresponding cut-off points. Ongoing work seeks to validate these findings in a larger cohort of pediatric hydrocephalic patients with varying etiologies. Full article

Inflammatory bowel disease (IBD) is a chronic immune-mediated condition of the gastrointestinal tract, characterized by dysregulated inflammatory responses throughout the gastrointestinal tract. It includes two major phenotypes, Crohn’s disease (CD) and ulcerative colitis (UC), which present with varying gastrointestinal and systemic symptoms. The pathophysiology of IBD is multifactorial including genetic predisposition, mucosal and epithelial dysfunction, environmental injury, and both innate and adaptive immune response abnormalities. Several predisposing genetic factors have been associated with IBD explaining the strong hereditary risk for both CD and UC. For example, Caspase Recruitment Domain 9 (CARD9) variant rs10781499 increases risk for IBD, while other variants are specific to either CD or UC. CD is related to loss-of-function mutations in the nucleotide oligomerization domain containing the protein 2 (NOD2) gene and Autophagy-Related 16-like 1 (ATG16L1) gene. UC risk is increased particularly in Chinese populations by the A-1661G polymorphism of the Cytotoxic T-lymphocyte antigen 4 (CTLA-4) gene. This abnormal CTLA-4 interferes with B- and T-cell responses causing predisposition to autoimmune conditions. Previous studies suggested that IBD results from breakdown of the adaptive immune system, primarily of T-cells. However, new evidence suggests that a primary breakdown of the innate immune system in both CD and UC increases susceptibility to invasion by viruses and bacteria, with a compensatory overactivation of the adaptive immune system as a result. When this viral and microbial invasion continues, further damage is incurred, resulting in a downward cycle of further cytokine activation and epithelial damage. Released biomarkers also affect the permeability of the epithelial membrane, including lactoferrin, nitric oxide (NO), myeloperoxidase (MPO) and its activation of hypochlorous acid, matrix metalloproteinases (MMPs), especially MMP-9, omentin-1, and others. Increased macrophage and dendritic cell dysfunction, increased neutrophil activity, increased numbers of innate lymphoid cells, increased T-cells with decreased regulatory T-cells (Tregs), and changes in B-cell populations and immunoglobulin (Ig) functions are all associated with IBD. Finally, treatment of IBD has typically consisted of medical management (e.g., aminosalicylates and corticosteroids) and lifestyle modification, and surgical intervention in extreme cases. New classes of medications with more favorable side effect profiles include anti-integrin antibodies, vedolizumab, etrolizumab, and carotegrast methyl. Additionally, fecal microbiota transplant (FMT) is a newer area of research for treatment of IBD along with TNF-blockers, JAK inhibitors, and S1PR modulators. However, expense and long preparation time have limited the usefulness of FMT. Full article

Gout is a form of sterile inflammatory arthritis in which monosodium urate (MSU) crystals deposit and provoke a neutrophil-predominant response, primarily driven by activation of the NACHT, leucine-rich repeat, and pyrin domain-containing protein 3 (NLRP3) inflammasome. Here, we show that auranofin, a Food and Drug Administration (FDA)-approved anti-rheumatic agent, exerts anti-inflammatory effects in both in vitro and in vivo models of gout. Auranofin inhibited NLRP3 inflammasome activation in human THP-1 cells and murine macrophages, leading to reduced cleavage of caspase-1, interleukin-1β (IL-1β), and interleukin-18 (IL-18). In MSU crystal-induced mouse models, auranofin treatment reduced paw swelling, serum cytokine levels, and tissue inflammation. Notably, auranofin suppressed neutrophil migration and decreased expression of C-X-C motif chemokine ligand 1 (CXCL1) in inflamed foot tissue and air-pouch exudates. Mechanistically, auranofin disrupted the interleukin-33 (IL-33)/suppression of tumorigenicity 2 (ST2) axis, a key signaling pathway promoting neutrophil recruitment. Overexpression of IL-33 abolished the anti-inflammatory effects of auranofin, highlighting the central role of IL-33 in gout pathogenesis. Together, our findings suggest that auranofin alleviates MSU-induced inflammation by concurrently inhibiting NLRP3 inflammasome activation and IL-33-mediated neutrophil recruitment, supporting its potential as a dual-action therapeutic candidate for gout. Full article

Inflammatory bowel disease (IBD) and primary sclerosing cholangitis (PSC) are chronic immune-mediated inflammatory diseases (IMIDs) that affect the gastrointestinal and hepatobiliary systems. They are characterized by persistent inflammation, potentially progressive fibrosis, and an elevated risk of developing cholangiocarcinoma and colorectal cancer. IBD and PSC share phenotypical, genetic, and immunological features, largely due to the central role of immune cell dysregulation. Despite their increasing global prevalence, the underlying drivers remain poorly understood, and effective treatment options are still lacking. Efforts towards an improved comprehension of their pathogenic mechanisms are therefore pivotal. Emerging evidence highlights the role of canonical ASC-dependent inflammasomes—multiprotein bioactive Interleukin (IL)-1-producing complexes of the innate immune system—and serum amyloid A (SAA) as key structures of gastrointestinal and hepatobiliary inflammation, tissue remodeling, stromal crosstalk, and fibrosis. In this review, we explore immunological connections and analogies between IBD and PSC, highlighting the converging roles of canonical ASC-dependent inflammasomes, the IL-1 superfamily, SAA, and sustained gut microbiota-driven chronic inflammation in disease pathology and their surging potential as therapeutic targets across the gut–liver axis. Full article

Increasing evidence reveals that the deregulation of cellular antioxidant response with advancing age, resulting in the continuing amplification of oxidative stress-induced inflammatory response, is a pre-eminent cause for the onset of aging-related disease states, including blinding diseases. However, several safeguards, like an antioxidant defense system, are genetically in place to maintain redox homeostasis. Nonetheless, if the homeostatic capacity of such systems fails (like in aging), an inflammatory pathway elicited by excessive oxidative stress-evoked aberrant NLRP3 (NOD, LRR- and pyrin domain-containing protein 3) inflammasome activation can become pathogenic and lead to disease states. Among all known inflammasomes, NLRP3 is the most studied and acts as an intracellular sensor to detect danger(s). Upon activation, NLRP3 recruits apoptosis-associated speck-like protein containing a CARD (ASC) oligomerization and facilitates the recruitment of activated Caspase-1 (Cas-1), which results in the release of inflammatory cytokines, IL-1β and IL-18 and the activation of GasderminD, an executor of pyroptosis. NLRP3 inflammasome is tightly regulated in favor of cell health. However, when and how the activation of NLRP3 and its inflammatory components goes awry, leading to cellular derangement, and what regulatory factors are involved in the normal physiological and aging/oxidative conditions will be included in this review. Also, we address the latest findings to highlight the connection between oxidative stress, antioxidants, and NLRP3 activation as this begets aging diseases and explore the cellular pathways that are in place to regulate oxidative-induced inflammations and the pathobiological consequences of dysregulated inflammatory responses and vice versa. Full article

Extremely premature infants are at significant risk for developing bronchopulmonary dysplasia (BPD) and neurodevelopmental impairment (NDI). Although BPD is a predictor of poor neurodevelopmental outcomes, it is currently unknown how BPD contributes to brain injury and long-term NDI in pre-term infants. Extracellular vesicles (EVs) are small, membrane-bound structures released from cells into the surrounding environment. EVs are involved in inter-organ communication in diverse pathological processes. Inflammasomes are large, multiprotein complexes that are part of the innate immune system and are responsible for triggering inflammatory responses and cell death. Apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) is pivotal in inflammasome assembly and activating inflammatory caspase-1. Activated caspase-1 cleaves gasdermin D (GSDMD) to release a 30 kD N-terminal domain that can form membrane pores, leading to lytic cell death, also known as pyroptosis. Activated caspase-1 can also cleave pro-IL-1β and pro-IL-18 to their active forms, which can be rapidly released through the GSDMD pores to induce inflammation. Recent evidence has emerged that activation of inflammasomes is associated with neonatal lung and brain injury, and inhibition of inflammasomes reduces hyperoxia-induced neonatal lung and brain injury. Additionally, multiple studies have demonstrated that hyperoxia stimulates the release of lung-derived EVs that contain inflammasome cargos. Adoptive transfer of these EVs into the circulation of normal neonatal mice and rats induces brain inflammatory injury. This review focuses on EV–inflammasomes’ roles in mediating lung-to-brain crosstalk via EV-dependent and EV-independent mechanisms critical in BPD, brain injury, and NDI pathogenesis. EV–inflammasomes will be discussed as potential therapeutic targets for neonatal lung and brain injury. Full article

Background/Objectives: Dermal fibroblasts (DFs) are key participants in skin hypertrophic scarring, and their properties are being studied to identify the molecular and cellular mechanisms underlying the pathogenesis of skin scarring. Methods: In the present work, we performed a comparative analysis of DFs isolated from normal skin (normal dermal fibroblasts, NDFs), and hypertrophic scar skin (hypertrophic scar fibroblasts, HTSFs). The fibroblasts were karyotyped and phenotyped, and experiments on growth rate, wound healing, and single-cell motility were conducted. Results: Comparative analysis revealed a minor karyotype difference between cells. However, HTSFs are characterized by higher proliferation level and motility compared to NDFs. These significant differences may be associated with quantitative and qualitative differences in the cell secretome. A proteomic comparison of NDF and HTSF found that differences were associated with metabolic proteins reflecting physiological differences between the two cells lines. Numerous unique proteins were found only in the vesicular phase of vHTSFs. Some proteins involved in cell proliferation (protein-glutamine gamma-glutamyltransferase K) and cell motility (catenin delta-1), which regulate gene transcription and the activity of Rho family GTPases and downstream cytoskeletal dynamics, were identified. A number of proteins which potentially play a role in fibrosis and inflammation (mucin-5B, CD97, adhesion G protein-coupled receptor E2, antileukoproteinase, protein S100-A8 and S100-A9, protein caspase recruitment domain-containing protein 14) were detected in vHTSFs. Conclusions: A comparative analysis of primary cell cultures revealed their various properties, especially in the cell secretome. These proteins may be considered promising target molecules for developing treatment or prevention strategies for pathological skin scarring. Full article

Aneurysmal subarachnoid hemorrhage (aSAH) is caused by abnormal blood vessel dilation and subsequent rupture, resulting in blood pooling in the subarachnoid space. This neurological insult results in the activation of the inflammasome, a multiprotein complex that processes pro-inflammatory interleukin (IL)-1 cytokines leading to morbidity and mortality. Moreover, increases in inflammasome proteins are associated with clinical deterioration in many neurological diseases. Limited studies have investigated inflammasome protein expression following aSAH. Reliable markers of the inflammatory response associated with aSAH may allow for earlier detection of patients at risk for complications and aid in the identification of novel pharmacologic targets. Here, we investigated whether inflammasome signaling proteins may serve as potential biomarkers of the inflammatory response in aSAH. Serum and cerebrospinal fluid (CSF) from fifteen aSAH subjects and healthy age-matched controls and hydrocephalus (CSF) no-aneurysm controls were evaluated for levels of inflammasome signaling proteins and downstream pro-inflammatory cytokines. Protein measurements were carried out using Simple Plex and Single-Molecule Array (Simoa) technology. The area under the curve (AUC) was calculated using receiver operating characteristics (ROCs) to obtain information on biomarker reliability, specificity, sensitivity, cut-off points, and likelihood ratio. In addition, a Spearman r correlation matrix was performed to determine the correlation between inflammasome protein levels and clinical outcome measures. aSAH subjects demonstrated elevated caspase-1, apoptosis-associated speck-like protein with a caspase recruiting domain (ASC), IL-18 and IL-1β levels in serum, and CSF when compared to controls. Each of these proteins was found to be a promising biomarker of inflammation in aSAH in the CSF. In addition, ASC, caspase-1, and IL-1β were found to be promising biomarkers of inflammation in aSAH in serum. Furthermore, we found that elevated levels of inflammasome proteins in serum are useful to predict worse functional outcomes following aSAH. Thus, the determination of inflammasome protein levels in CSF and serum in aSAH may be utilized as reliable biomarkers of inflammation in aSAH and used clinically to monitor patient outcomes. Full article

Dementia is a group of symptoms including memory loss, language difficulties, and other types of cognitive and functional impairments that affects 57 million people worldwide, with the incidence expected to double by 2040. Therefore, there is an unmet need to develop reliable biomarkers to diagnose early brain impairments so that emerging interventions can be applied before brain degeneration. Here, we performed biomarker analyses for apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), and amyloid-β 42/40 (Aβ_42/40) ratio in the plasma of older adults. Participants had blood drawn at baseline and underwent two annual clinical and cognitive evaluations. The groups tested either cognitively normal on both evaluations (N_N), cognitively normal year 1 but cognitively impaired year 2 (N_I), or cognitively impaired on both evaluations (I_I). ASC was elevated in the plasma of the N_I group compared to the N_N and I_I groups. Additionally, Aβ₄₂ was increased in the plasma in the N_I and I_I groups compared to the N_N group. Importantly, the area under the curve (AUC) for ASC in participants older than 70 years old in N_N vs. N_I groups was 0.81, indicating that ASC is a promising plasma biomarker for early detection of cognitive decline. Full article

The ubiquitous soil-associated fungus Cryptococcus neoformans causes pneumonia that may progress to fatal meningitis. Recognition of fungal cell walls by C-type lectin receptors (CLRs) has been shown to trigger the host immune response. Caspase recruitment domain-containing protein 9 (Card9) is an intracellular adaptor that is downstream of several CLRs. Experimental studies have implicated Card9 in host resistance against C. neoformans; however, the mechanisms that are associated with susceptibility to progressive infection are not well defined. To further characterize the role of Card9 in cryptococcal infection, Card9^em1Sq mutant mice that lack exon 2 of the Card9 gene on the Balb/c genetic background were created using CRISPR-Cas9 genome editing technology and intratracheally infected with C. neoformans 52D. Card9^em1Sq mice had significantly higher lung and brain fungal burdens and shorter survival after C. neoformans 52D infection. Susceptibility of Card9^em1Sq mice was associated with lower pulmonary cytokine and chemokine production, as well as reduced numbers of CD4⁺ lymphocytes, neutrophils, monocytes, and dendritic cells in the lungs. Histological analysis and intracellular cytokine staining of CD4⁺ T cells demonstrated a Th2 pattern of immunity in Card9^em1Sq mice. These findings demonstrate that Card9 broadly regulates the host inflammatory and immune response to experimental pulmonary infection with a moderately virulent strain of C. neoformans. Full article

Inflammasomes comprise a group of protein complexes with fundamental roles in the induction of inflammation. Upon sensing stress factors, their assembly induces the activation and release of the pro-inflammatory cytokines interleukin (IL)-1β and -18 and a lytic type of cell death, termed pyroptosis. Recently, CARD8 has joined the group of inflammasome sensors. The carboxy-terminal part of CARD8, consisting of a function-to-find-domain (FIIND) and a caspase activation and recruitment domain (CARD), resembles that of NLR family pyrin domain containing 1 (NLRP1), which is recognized as the main inflammasome sensor in human keratinocytes. The interaction with dipeptidyl peptidases 8 and 9 (DPP8/9) represents an activation checkpoint for both sensors. CARD8 and NLRP1 are activated by viral protease activity targeting their amino-terminal region. However, CARD8 also has some unique features compared to the established inflammasome sensors. Activation of CARD8 occurs independently of the inflammasome adaptor protein apoptosis-associated speck-like protein containing a CARD (ASC), leading mainly to pyroptosis rather than the activation and secretion of pro-inflammatory cytokines. CARD8 was also shown to have anti-inflammatory and anti-apoptotic activity. It interacts with, and inhibits, several proteins involved in inflammation and cell death, such as the inflammasome sensor NLRP3, CARD-containing proteins caspase-1 and -9, nucleotide-binding oligomerization domain containing 2 (NOD2), or nuclear factor kappa B (NF-κB). Single nucleotide polymorphisms (SNPs) of CARD8, some of them occurring at high frequencies, are associated with various inflammatory diseases. The molecular mechanisms underlying the different pro- and anti-inflammatory activities of CARD8 are incompletely understood. Alternative splicing leads to the generation of multiple CARD8 protein isoforms. Although the functional properties of these isoforms are poorly characterized, there is evidence that suggests isoform-specific roles. The characterization of the functions of these isoforms, together with their cell- and disease-specific expression, might be the key to a better understanding of CARD8’s different roles in inflammation and inflammatory diseases. Full article

Cryptococcus is a genus of fungal pathogens that can infect and cause disease in a range of host species and is particularly prominent in koalas (Phascolarctos cinerus). Like other host species, koalas display a range of outcomes upon exposure to environmental Cryptococcus, from external nasal colonization to asymptomatic invasive infection and, in rare cases, severe clinical disease resulting in death. Host factors contributing to these varied outcomes are poorly understood. Due to their close relationship with eucalypt trees (a key environmental niche for Cryptococcus gattii) and suspected continual exposure to the pathogen, koalas provide a unique opportunity to examine host susceptibility in natural infections. Caspase recruitment domain-containing protein 9 (CARD9) is a key intracellular signaling protein in the fungal innate immune response. Humans with mutations in CARD9 succumb to several different severe and chronic fungal infections. This study is the first to sequence and explore CARD9 variation in multiple koalas using Sanger sequencing. Four CARD9 exons were successfully sequenced in 22 koalas from a New South Wales, Australia population. We found minimal variation between koalas across all four exons, an observation that was also made when CARD9 sequences were compared between koalas and six other species, including humans and mice. Ten single-nucleotide polymorphisms (SNP) were identified in this study and explored in the context of cryptococcal exposure outcomes. While we did not find any significant association with variation in cryptococcal outcomes, we found a high degree of conservation between species at several SNP loci that requires further investigation. The findings from this study lay the groundwork for further investigations of CARD9 and Cryptococcus both in koalas and other species, and highlight several considerations for future studies. Full article

Chronic venous disease (CVD) comprises a spectrum of morphofunctional disorders affecting the venous system, affecting approximately 1 in 3 women during gestation. Emerging evidence highlights diverse maternofetal implications stemming from CVD, particularly impacting the placenta. While systemic inflammation has been associated with pregnancy-related CVD, preliminary findings suggest a potential link between this condition and exacerbated inflammation in the placental tissue. Inflammasomes are major orchestrators of immune responses and inflammation in different organs and systems. Notwithstanding the relevance of inflammasomes, specifically the NLRP3 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3)- which has been demonstrated in the placentas of women with different obstetric complications, the precise involvement of this component in the placentas of women with CVD remains to be explored. This study employs immunohistochemistry and real-time PCR (RT-qPCR) to examine the gene and protein expression of key components in both canonical and non-canonical pathways of the NLRP3 inflammasome (NLRP3, ASC—apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain—caspase 1, caspase 5, caspase 8, and interleukin 1β) within the placental tissue of women affected by CVD. Our findings reveal a substantial upregulation of these components in CVD-affected placentas, indicating a potential pathophysiological role of the NLRP3 inflammasome in the development of this condition. Subsequent investigations should focus on assessing translational interventions addressing this dysregulation in affected patient populations. Full article

Caspase-5 is a protease that induces inflammation in response to lipopolysaccharide (LPS), a component of the cell envelope of Gram-negative bacteria. The expression level of the CASP5 gene is very low in the basal state, but strongly increases in the presence of LPS. Intracellular LPS binds to the caspase activation and recruitment domain (CARD) of caspase-5, leading to the formation of a non-canonical inflammasome. Subsequently, the catalytic domain of caspase-5 cleaves gasdermin D and thereby facilitates the formation of cell membrane pores through which pro-inflammatory cytokines of the interleukin-1 family are released. Caspase-4 is also able to form a non-canonical inflammasome upon binding to LPS, but its expression is less dependent on LPS than the expression of caspase-5. Caspase-4 and caspase-5 have evolved via the duplication of a single ancestral gene in a subclade of primates, including humans. Notably, the main biomedical model species, the mouse, has only one ortholog, namely caspase-11. Here, we review the structural features and the mechanisms of regulation that are important for the pro-inflammatory roles of caspase-5. We summarize the interspecies differences and the evolution of pro-inflammatory caspases in mammals and discuss the potential roles of caspase-5 in the defense against Gram-negative bacteria and in sepsis. Full article

The caspase recruitment domain-containing protein 9 (CARD9) is an intracellular adaptor protein that is abundantly expressed in cells of the myeloid lineage, such as neutrophils, macrophages, and dendritic cells. CARD9 plays a critical role in host immunity against infections caused by fungi, bacteria, and viruses. A CARD9 deficiency impairs the production of inflammatory cytokines and chemokines as well as migration and infiltration, thereby increasing susceptibility to infections. However, CARD9 signaling varies depending on the pathogen causing the infection. Furthermore, different studies have reported altered CARD9-mediated signaling even with the same pathogen. Therefore, this review focuses on and elucidates the current literature on varied CARD9 signaling in response to various infectious stimuli in humans and experimental mice models. Full article