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Tropical Medicine and Infectious Disease May 2024, a zoonotic parasite, can invade the human central nervous system (CNS) and cause acute eosinophilic meningitis or eosinophilic meningoencephalitis. Mice infected with...
, a zoonotic parasite, can invade the human central nervous system (CNS) and cause acute eosinophilic meningitis or eosinophilic meningoencephalitis. Mice infected with show elevated levels of pro-inflammatory cytokines, plasminogen activators, and matrix metalloproteinase-9, resulting in disruption of the blood-brain barrier (BBB) and immune cell infiltration into the CNS. Caveolin-1 (Cav-1) regulates the permeability of the BBB, which affects immune cells and cerebrospinal fluid. This intricate interaction ultimately fuels the progression of brain damage and edema. This study aims to investigate the regulatory role of Cav-1 in the pathogenesis of meningoencephalitis induced by infection. We investigated pathological alterations by triphenyl-tetrazolium chloride, brain water content, BBB permeability, Western blot analysis, and gelatin zymography in BALB/c mice after . The study evaluates the critical role of Cav-1 regulation through the TLR4/MyD88 signaling pathway, modulates tight junction proteins, influences BBB permeability, and contributes to brain damage in -induced meningoencephalitis.
PubMed: 38922036
DOI: 10.3390/tropicalmed9060124 -
Journal of Fungi (Basel, Switzerland) Jun 2024The ubiquitous soil-associated fungus causes pneumonia that may progress to fatal meningitis. Recognition of fungal cell walls by C-type lectin receptors (CLRs) has...
The ubiquitous soil-associated fungus 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 ; 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 mutant mice that lack exon 2 of the gene on the Balb/c genetic background were created using CRISPR-Cas9 genome editing technology and intratracheally infected with 52D. Card9 mice had significantly higher lung and brain fungal burdens and shorter survival after 52D infection. Susceptibility of Card9 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 mice. These findings demonstrate that Card9 broadly regulates the host inflammatory and immune response to experimental pulmonary infection with a moderately virulent strain of .
PubMed: 38921420
DOI: 10.3390/jof10060434 -
Journal of Fungi (Basel, Switzerland) Jun 2024Animal models are frequently used as surrogates to understand human disease. In the fungal pathogen species complex, several variations of a mouse model of disease were... (Review)
Review
Animal models are frequently used as surrogates to understand human disease. In the fungal pathogen species complex, several variations of a mouse model of disease were developed that recapitulate different aspects of human disease. These mouse models have been implemented using various inbred and outbred mouse backgrounds, many of which have genetic differences that can influence host response and disease outcome. In this review, we will discuss the most commonly used inbred mouse backgrounds in infection models.
PubMed: 38921412
DOI: 10.3390/jof10060426 -
Frontiers in Endocrinology 2024Acromegaly is a rare endocrine disorder caused by hypersecretion of growth hormone (GH) from a pituitary adenoma. Elevated GH levels stimulate excess production of...
UNLABELLED
Acromegaly is a rare endocrine disorder caused by hypersecretion of growth hormone (GH) from a pituitary adenoma. Elevated GH levels stimulate excess production of insulin-like growth factor 1 (IGF-1) which leads to the insidious onset of clinical manifestations. The most common primary central nervous system (CNS) tumors, meningiomas originate from the arachnoid layer of the meninges and are typically benign and slow-growing. Meningiomas are over twice as common in women as in men, with age-adjusted incidence (per 100,000 individuals) of 10.66 and 4.75, respectively. Several reports describe co-occurrence of meningiomas and acromegaly. We aimed to determine whether patients with acromegaly are at elevated risk for meningioma. Investigation of the literature showed that co-occurrence of a pituitary adenoma and a meningioma is a rare phenomenon, and the majority of cases involve GH-secreting adenomas. To the best of our knowledge, a systematic review examining the association between meningiomas and elevated GH levels (due to GH-secreting adenomas in acromegaly or exposure to exogenous GH) has never been conducted. The nature of the observed coexistence between acromegaly and meningioma -whether it reflects causation or mere co-association -is unclear, as is the pathophysiologic etiology.
SYSTEMATIC REVIEW REGISTRATION
https://www.crd.york.ac.uk/prospero/, identifier CRD42022376998.
Topics: Humans; Meningioma; Acromegaly; Meningeal Neoplasms; Human Growth Hormone; Risk Factors; Adenoma
PubMed: 38919490
DOI: 10.3389/fendo.2024.1407615 -
PloS One 2024Meningiomas, the most prevalent primary benign intracranial tumors, often exhibit complicated levels of adhesion to adjacent normal tissues, significantly influencing...
Meningiomas, the most prevalent primary benign intracranial tumors, often exhibit complicated levels of adhesion to adjacent normal tissues, significantly influencing resection and causing postoperative complications. Surgery remains the primary therapeutic approach, and when combined with adjuvant radiotherapy, it effectively controls residual tumors and reduces tumor recurrence when complete removal may cause a neurologic deficit. Previous studies have indicated that slip interface imaging (SII) techniques based on MR elastography (MRE) have promise as a method for sensitively determining the presence of tumor-brain adhesion. In this study, we developed and tested an improved algorithm for assessing tumor-brain adhesion, based on recognition of patterns in MRE-derived normalized octahedral shear strain (NOSS) images. The primary goal was to quantify the tumor interfaces at higher risk for adhesion, offering a precise and objective method to assess meningioma adhesions in 52 meningioma patients. We also investigated the predictive value of MRE-assessed tumor adhesion in meningioma recurrence. Our findings highlight the effectiveness of the improved SII technique in distinguishing the adhesion degrees, particularly complete adhesion. Statistical analysis revealed significant differences in adhesion percentages between complete and partial adherent tumors (p = 0.005), and complete and non-adherent tumors (p<0.001). The improved technique demonstrated superior discriminatory ability in identifying tumor adhesion patterns compared to the previously described algorithm, with an AUC of 0.86 vs. 0.72 for distinguishing complete adhesion from others (p = 0.037), and an AUC of 0.72 vs. 0.67 for non-adherent and others. Aggressive tumors exhibiting atypical features showed significantly higher adhesion percentages in recurrence group compared to non-recurrence group (p = 0.042). This study validates the efficacy of the improved SII technique in quantifying meningioma adhesions and demonstrates its potential to affect clinical decision-making. The reliability of the technique, coupled with potential to help predict meningioma recurrence, particularly in aggressive tumor subsets, highlights its promise in guiding treatment strategies.
Topics: Humans; Meningioma; Elasticity Imaging Techniques; Female; Middle Aged; Male; Meningeal Neoplasms; Aged; Adult; Magnetic Resonance Imaging; Neoplasm Recurrence, Local; Tissue Adhesions; Algorithms
PubMed: 38917107
DOI: 10.1371/journal.pone.0305247 -
MBio Jun 2024causes cryptococcosis, one of the most prevalent fungal diseases, generally characterized by meningitis. There is a limited and not very effective number of drugs...
UNLABELLED
causes cryptococcosis, one of the most prevalent fungal diseases, generally characterized by meningitis. There is a limited and not very effective number of drugs available to combat this disease. In this manuscript, we show the host defense peptide mimetic brilacidin (BRI) as a promising antifungal drug against . BRI can affect the organization of the cell membrane, increasing the fungal cell permeability. We also investigated the effects of BRI against the model system by analyzing libraries of mutants grown in the presence of BRI. In , BRI also affects the cell membrane organization, but in addition the cell wall integrity pathway and calcium metabolism. experiments show BRI significantly reduces survival inside macrophages and partially clears lung infection in an immunocompetent murine model of invasive pulmonary cryptococcosis. We also observed that BRI interacts with caspofungin (CAS) and amphotericin (AmB), potentiating their mechanism of action against . BRI + CAS affects endocytic movement, calcineurin, and mitogen-activated protein kinases. Our results indicate that BRI is a novel antifungal drug against cryptococcosis.
IMPORTANCE
Invasive fungal infections have a high mortality rate causing more deaths annually than tuberculosis or malaria. Cryptococcosis, one of the most prevalent fungal diseases, is generally characterized by meningitis and is mainly caused by two closely related species of basidiomycetous yeasts, and . There are few therapeutic options for treating cryptococcosis, and searching for new antifungal agents against this disease is very important. Here, we present brilacidin (BRI) as a potential antifungal agent against . BRI is a small molecule host defense peptide mimetic that has previously exhibited broad-spectrum immunomodulatory/anti-inflammatory activity against bacteria and viruses. BRI alone was shown to inhibit the growth of , acting as a fungicidal drug, but surprisingly also potentiated the activity of caspofungin (CAS) against this species. We investigated the mechanism of action of BRI and BRI + CAS against . We propose BRI as a new antifungal agent against cryptococcosis.
PubMed: 38916308
DOI: 10.1128/mbio.01031-24 -
Cureus May 2024Background Spinal dysraphism, characterized by incomplete closure of neural and bone spinal structures, manifests as congenital fusion abnormalities along the dorsal...
Background Spinal dysraphism, characterized by incomplete closure of neural and bone spinal structures, manifests as congenital fusion abnormalities along the dorsal midline, involving the skin, subcutaneous tissue, meninges, vertebrae, and neural tissue. Magnetic resonance imaging (MRI), the preferred imaging modality for assessing spinal dysraphism across all age groups, provides direct visualization of the spinal cord without the need for contrast or ionizing radiation while also eliminating bone artifacts and allowing multiplanar imaging. The objective of this study was to evaluate the range of spinal dysraphism lesions and assess the significance of MRI in their evaluation. Methodology Thirty patients with suspected spinal dysraphism underwent evaluation at the Medical College Hospital and Study Centre in Vijayapur, India. This cross-sectional observational study included patients diagnosed or provisionally diagnosed with spinal dysraphism based on clinical and imaging profiles. Cases were identified through preliminary findings on radiographs. Results The study encompassed individuals aged one month to 20 years, with the largest proportion of patients (36.67%) falling within the 1-5-year age group. Spina bifida was the most prevalent spinal abnormality, accounting for 70% of cases. In 12 patients (40%), the most prevalent location of involvement was the lumbosacral spine. Conclusion MRI provides excellent tissue differentiation, particularly of lipomatous tissue, with reproducible and comprehensive section planes and relative operator independence. Moreover, MRI is beneficial for children with suspected spinal dysraphism as it can be performed without ionizing radiation, biological risks, or the need for intrathecal contrast media.
PubMed: 38916024
DOI: 10.7759/cureus.60972 -
Cureus May 2024This case emphasizes the significance of recognizing and managing species. Here, we present a unique case of species isolated from the cerebrospinal fluid of a...
This case emphasizes the significance of recognizing and managing species. Here, we present a unique case of species isolated from the cerebrospinal fluid of a 60-year-old female with recently diagnosed human immunodeficiency virus (HIV) and small cell carcinoma of the lung. Management involved a two-week course of intravenous vancomycin. species are infrequently encountered in clinical practice. Sharing this case report aims to enhance the limited understanding of species infections and encourages discussion among healthcare professionals regarding its diagnosis and management.
PubMed: 38915964
DOI: 10.7759/cureus.61072 -
BioRxiv : the Preprint Server For... Jun 2024Group B (GBS) asymptomatically colonizes the vagina but can opportunistically ascend to the uterus and be transmitted vertically during pregnancy, resulting in neonatal...
UNLABELLED
Group B (GBS) asymptomatically colonizes the vagina but can opportunistically ascend to the uterus and be transmitted vertically during pregnancy, resulting in neonatal pneumonia, bacteremia and meningitis. GBS is a leading etiologic agent of neonatal infection and understanding the mechanisms by which GBS persists within the polymicrobial female genital mucosa has potential to mitigate subsequent transmission and disease. Type VIIb secretion systems (T7SSb) are encoded by Firmicutes and often mediate interbacterial competition using LXG toxins that contain conserved N-termini important for secretion and variable C-terminal toxin domains that confer diverse biochemical activities. Our recent work characterized a role for the GBS T7SSb in vaginal colonization and ascending infection but the mechanisms by which the T7SSb promotes GBS persistence in this polymicrobial niche remain unknown. Herein, we investigate the GBS T7SS in interbacterial competition and GBS niche establishment in the female genital tract. We demonstrate GBS T7SS-dependent inhibition of mucosal pathobiont both using predator-prey assays and in the murine genital tract and found that a GBS LXG protein encoded within the T7SS locus (herein named group B streptococcal L XG T oxin A ) that contributes to these phenotypes. We identify BltA as a T7SS substrate that is toxic to and upon induction of expression along with associated chaperones. Finally, we show that BltA and its chaperones contribute to GBS vaginal colonization. Altogether, these data reveal a role for a novel T7b-secreted toxin in GBS mucosal persistence and competition.
IMPORTANCE
Competition between neighboring, non-kin bacteria is essential for microbial niche establishment in mucosal environments. Gram-positive bacteria encoding T7SSb have been shown to engage in competition through export of LXG-motif containing toxins, but these have not been characterized in group B (GBS), an opportunistic colonizer of the polymicrobial female genital tract. Here, we show a role for GBS T7SS in competition with mucosal pathobiont , both and . We further find that a GBS LXG protein contributing to this antagonism is exported by the T7SS and is intracellularly toxic to other bacteria; therefore, we have named this protein group B streptococcal L XG T oxin A (BltA). Finally, we show that BltA and its associated chaperones promote persistence within female genital tract tissues These data reveal previously unrecognized mechanisms by which GBS may compete with other mucosal opportunistic pathogens to persist within the female genital tract.
PubMed: 38915665
DOI: 10.1101/2024.06.10.598350 -
BioRxiv : the Preprint Server For... Jun 2024The fungus is an opportunistic pathogen of people that reprograms its translatome to facilitate adaptation and virulence within the host. We studied the role of...
UNLABELLED
The fungus is an opportunistic pathogen of people that reprograms its translatome to facilitate adaptation and virulence within the host. We studied the role of Hog1/p38 in reprogramming translation during thermal stress adaptation, and found that this pathway acts on translation via crosstalk with the Gcn2 pathway, a well-studied regulator of general translation control. Using a combination of molecular assays and phenotypic analysis, we show that increased output from the Gcn2 pathway in a Hog1 deletion mutant is associated with rescue of thermal stress adaptation at both molecular and phenotypic scales. We characterize known outputs of the Hog1 pathway during thermal stress as either Gcn2-dependent or Gcn2-independent, and demonstrate that Hog1 activation regulates the Gcn2 pathway even in the absence of thermal stress. Finally, we implicate this phenomenon in another Hog1-regulated process, morphogenesis, and recapitulate Hog1-Gcn2 crosstalk in the distantly related fungal pathogen, Our results point to an important link between the stress response machinery and translation control, and clarify the etiology of phenotypes associated with Hog1 deletion. More broadly, this study highlights complex interplay between core conserved signal transduction pathways and the utility of molecular assays to better understand how these pathways are connected.
IMPORTANCE
is an opportunistic pathogen of people that causes deadly cryptococcal meningitis, which is is responsible for an estimated 19% of AIDS-related mortality. When left untreated, cryptococcal meningitis is uniformly fatal, and in patients receiving the most effective antifungal regimens, mortality remains high. Thus, there is a critical need to identify additional targets that play a role in adaptation to the human host and virulence. This study explores the role of the stress response kinases Hog1 and Gcn2 in thermoadaptation, which is pre-requisite for virulence. Our results show that compensatory signaling occurs via the Gcn2 pathway when Hog1 is deleted, and that disruption of both pathways increases sensitivity to thermal stress. Importantly, our study highlights the insufficiency of using single gene deletion mutants to study gene function, since many phenotypes associated with Hog1 deletion were driven by Gcn2 signaling in this background, rather than loss of direct Hog1 activity.
PubMed: 38915642
DOI: 10.1101/2024.06.11.598457