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1.
Immunol Invest ; : 1-20, 2024 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-39495019

RESUMO

BACKGROUND: Most of the investigations related to inflammasome activation during HIV infection have focused on the receptor NLRP3 and innate immune cells such as monocytes/macrophages. However, during the past years, inflammasome activation has also been explored in lymphocytes, and novel sensors, other than the NLRP3, have been shown to play a role in the biology of these cells. Here, we hypothesized that NLRP1 may be involved in CD4+ T cell dysregulation in people living with HIV (PLWH), therefore contributing to chronic inflammation and to the pathogenesis of non-HIV-associated diseases. METHODS: The activation of NLRP1 in CD4+ T cells was assessed ex-vivo and in-vitro by the meaning of anti-CD3/anti-CD28 and Talabostat/Val-boroPro (VbP) response. RESULTS: Our results showed that the NLRP1 inflammasome was activated in PLWH CD4+ T cells, and that the stimulation of CD4+ T cells resulted in increased response to anti-CD3/anti-CD28 and VbP. Functional variants in NLRP1 significantly affected the level of inflammatory dysregulation of CD4+ T cells, therefore explaining at least in part the association with CD4+ T-mediated diseases. CONCLUSION: PLWH CD4+ T cells are more prone to IL-1ß release and pyroptosis, therefore contributing to chronic inflammation.

3.
Front Immunol ; 15: 1466520, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39497817

RESUMO

Brucella abortus (B.abortus) is a zoonotic bacterial pathogen that causes chronic host infections. The eradication of brucellosis using antibiotic therapy is often incomplete or slow. In a mouse model, the predominance of alternatively activated macrophages (also known as M2) plays an essential role in sustaining chronic infection. The underlying functional mechanism by which M2 sustains chronic infection remains unclear. Here, we show that B. abortus can enter M2 via triggering receptor expressed on myeloid cells 2 (TREM2) and promotes the upregulation of TREM2 expression of M2 in a type IV secretion system (T4SS)-dependent manner. Increased TREM2 enhances B. abortus growth within M2 by suppressing intracellular ROS production, preventing M2 pyroptosis via suppression of mitochondrial ROS (mROS), and promoting M2 proliferation by increasing ß-catenin expression. In line with these results, downregulation of TREM2 expression suppressed B. abortus intracellular growth and M2 proliferation and induced M2 pyroptosis. In our mouse model, upregulation of TREM2 expression sustained the accumulation of M2 and B. abortus chronic infection, whereas downregulation of TREM2 expression restricted M2 proliferation and chronic infection. Collectively, our results suggest that targeting TREM2 may be a potential adjunct to antibiotic therapy for the prevention of chronic Brucella infection.


Assuntos
Brucella abortus , Brucelose , Macrófagos , Glicoproteínas de Membrana , Receptores Imunológicos , Regulação para Cima , Animais , Brucella abortus/fisiologia , Brucelose/imunologia , Camundongos , Glicoproteínas de Membrana/metabolismo , Glicoproteínas de Membrana/genética , Macrófagos/imunologia , Macrófagos/metabolismo , Macrófagos/microbiologia , Receptores Imunológicos/metabolismo , Receptores Imunológicos/genética , Doença Crônica , Modelos Animais de Doenças , Espécies Reativas de Oxigênio/metabolismo , Sistemas de Secreção Tipo IV/genética , Sistemas de Secreção Tipo IV/metabolismo , Humanos , Feminino , Camundongos Endogâmicos C57BL , Ativação de Macrófagos
4.
Artigo em Inglês | MEDLINE | ID: mdl-39440777

RESUMO

BACKGROUND: Chronic hepatitis B virus (HBV) infection remains a major global public health problem with devastating consequences, such as hepatocellular carcinoma. Currently, approved treatments are limited to interferon and nucleoside/nucleotide analogues for chronic hepatitis B and chemotherapy, radiotherapy, and surgery for cancer. Both treatments have their limitations, making complete cure an elusive goal. Therefore, the identification of new therapeutic targets using medicinal plants and the development of new antiviral and anticancer strategies are of utmost importance. OBJECTIVE: The aim of this review is to identify from the literature the substances and molecules of West African flora involved in the fight against chronic hepatitis B and liver cancer and to provide a summary of their mechanisms of action. METHODS: Pubmed, HAL open science, and Google Scholar literature search engines were used to identify medicinal plants and molecules from the West African flora. RESULTS: Among West African countries, Gambia and Niger had the highest prevalence of hepatitis B virus infection, and 09 West African countries had high rates of liver cancer. A number of studies carried out in Mali, Benin, Senegal, and Burkina Faso enabled us to list anti-HBV and anticancer plants, as well as a number of molecules isolated from plants found in West African regions. CONCLUSION: By offering a glimpse into the world of anti-HBV and anticancer molecules from West Africa, this review provides valuable information to support the future development of herbal antiviral and anticancer drugs.

5.
mBio ; : e0159824, 2024 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-39440973

RESUMO

Gammaherpesviruses are species-specific, ubiquitous pathogens that establish lifelong infection in their hosts and are associated with cancers, including B cell lymphomas. Type I and II interferons (IFNs) are critical for the control of acute and chronic gammaherpesvirus infection. However, the cell type-specific role of IFN signaling during natural infection is poorly defined and is masked by the altered viral pathogenesis observed in hosts with global IFN deficiencies. STAT1 is a constitutively expressed transcription factor that is critical for the effector function of type I and II IFNs. In this study, we defined the impact of B cell-specific STAT1 expression on gammaherpesvirus infection using murine gammaherpesvirus 68 (MHV68). While the acute stage of MHV68 infection was not affected, we found opposite, anatomic site-dependent effects of B cell-intrinsic STAT1 expression during chronic infection. Consistent with the antiviral role of STAT1, B cell-specific STAT1 expression attenuated the latent viral reservoir in peritoneal B cells of chronically infected mice. In contrast, STAT1 expression in splenic B cells supported the establishment of the latent MHV68 reservoir in germinal center B cells, revealing an unexpected proviral role of B cell-intrinsic STAT1 expression during chronic gammaherpesvirus infection. These STAT1-dependent MHV68 chronic infection phenotypes were fully recapitulated in the peritoneal cavity but not the spleen of mice with B cell-specific deficiency of type I IFN receptor. In summary, our study uncovers the intriguing combination of proviral and antiviral roles of B cell-intrinsic STAT1 expression during chronic gammaherpesvirus infection.IMPORTANCEInterferons (IFNs) execute broadly antiviral roles during acute and chronic viral infections. The constitutively expressed transcription factor STAT1 is a critical downstream effector of IFN signaling. Our studies demonstrate that B cell-intrinsic STAT1 expression has opposing and anatomic site-dependent roles during chronic gammaherpesvirus infection. Specifically, B cell-intrinsic STAT1 expression restricted gammaherpesvirus latent reservoir in the peritoneal cavity, consistent with the classical antiviral role of STAT1. In contrast, decreased STAT1 expression in splenic B cells led to the attenuated establishment of gammaherpesvirus latency and decreased latent infection of germinal center B cells, highlighting a novel proviral role of B cell-intrinsic STAT1 expression during chronic infection with a B cell-tropic gammaherpesvirus. Interestingly, B cell-specific type I IFN receptor deficiency primarily recapitulated the antiviral role of B cell-intrinsic STAT1 expression, suggesting the compensatory function of B cell-intrinsic type II IFN signaling or an IFN-independent proviral role of B cell-intrinsic STAT1 expression during chronic gammaherpesvirus infection.

6.
Virus Evol ; 10(1): veae073, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39399151

RESUMO

Accumulating evidence points to persistent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in immunocompromised individuals as a source of novel lineages. While intrahost evolution of the virus in chronically infected patients has previously been reported, existing knowledge is primarily based on samples from the nasopharynx. In this study, we investigate the intrahost evolution and genetic diversity that accumulated during a prolonged SARS-CoV-2 infection with the Omicron BF.7 sublineage, which is estimated to have persisted for >1 year in an immunosuppressed patient. Based on the sequencing of eight samples collected at six time points, we identified 87 intrahost single-nucleotide variants, 2 indels, and a 362-bp deletion. Our analysis revealed distinct viral genotypes in the nasopharyngeal (NP), endotracheal aspirate, and bronchoalveolar lavage samples. This suggests that NP samples may not offer a comprehensive representation of the overall intrahost viral diversity. Our findings not only demonstrate that the Omicron BF.7 sublineage can further diverge from its already exceptionally mutated state but also highlight that patients chronically infected with SARS-CoV-2 can develop genetically specific viral populations across distinct anatomic compartments. This provides novel insights into the intricate nature of viral diversity and evolution dynamics in persistent infections.

7.
Microb Pathog ; 197: 107020, 2024 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-39419459

RESUMO

OBJECTIVES: This study aimed to evaluate the efficacy of inhaled cationic antibiotics, including tobramycin (TOB) and colistin (CST), using an in vitro alginate bead model that simulates Pseudomonas aeruginosa lung biofilms. METHODS: Bioluminescent P. aeruginosa were encapsulated within alginate beads and dispersed in either Mueller-Hinton broth (MHB) or artificial sputum medium (ASM). The impact of bead size and culture medium on TOB and CST efficacy was assessed by monitoring bioluminescence kinetics, followed by colony-forming unit (CFU/mL) measurements. Antibiotic efficacy was quantified using a Hill inhibitory model to analyze variations in CFU/mL in response to TOB and CST concentrations. RESULTS: The TOB EC50 was found to be 8-fold higher when P. aeruginosa was encapsulated in larger beads (1200 µm) compared to smaller beads (60 µm). TOB efficacy further decreased twofold when larger beads were dispersed in ASM. In contrast, CST demonstrated superior efficacy, being four times more potent than TOB, with corresponding EC50 values of 20.5 ± 2.8 times MIC and 78.4 ± 10.2 times MIC, respectively. No change in MICs was observed for either antibiotic, even after exposing bacteria to 200 times the MIC. CONCLUSIONS: This P. aeruginosa biofilm model highlights how alginate and mucus modulated the efficacy of TOB and CST, and suggested the superior efficacy of CST in eradicating pulmonary biofilms.

8.
bioRxiv ; 2024 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-39372777

RESUMO

In murine models of visceral leishmaniasis (VL), parasitization of resident Kupffer cells (resKCs) is responsible for early growth of Leishmania infantum in the liver, which leads to granuloma formation and eventual parasite control. We employed the chronic VL model, and revealed an open niche established by KCs death and their migration outside of the sinusoids, resulting in their gradual replacement by monocyte-derived KCs (moKCs). While early granulomas were composed of resKCs, late granulomas were found outside of the sinusoids and contained resKC-derived macrophages, and monocyte-derived macrophages (momacs). ResKCs and moKCs within the sinusoids were identified as homeostatic/regulatory cells, while resKC-derived macrophages and momacs within late granulomas were pro-inflammatory. Despite the infection being largely confined to the resKC-derived macrophages, in the absence of monocyte recruitment, parasite control was strongly compromised. Macrophage heterogeneity, involving migration and reprogramming of resKCs, along with recruitment of monocyte-derived cells, is a hallmark of granuloma maturation and hepatic immunity in VL.

9.
Int J Gen Med ; 17: 4465-4474, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39372134

RESUMO

Purpose: Worldwide, chronic hepatitis B virus (CHB) infection is a public health concern, ultimately leading to liver cirrhosis and hepatocellular carcinoma. Currently, patients with CHB can be treated using polyethylene glycol (PEG)ylated interferon (PEG-IFN) antiviral therapy, which has both immune modulatory and antiviral properties. This study aimed to reveal the mechanism underlying the effect of PEG-IFN therapy, to rationally optimize this therapeutic option. Patients and Methods: Ten patients with CHB who were positive for the hepatitis B virus e antigen (HBeAg) and were receiving PEG-IFN treatment were enrolled. Clinical and virological parameters were monitored during 48 weeks of treatment. In addition, peripheral blood mononuclear cells (PBMCs) were collected from the 10 patients at 0, 24, and 36 weeks. RNA sequencing technology was used to analyze the RNA expression profile in the PBMC samples. Results: Following PEG-IFN treatment, we identified 217 differentially expressed genes (DEGs), most of which were upregulated. Gene ontology enrichment analysis of the DEGs revealed that they were enriched in 29 clusters, mainly associated with "antiviral defense", "innate immunity", "immunity", "defense response to virus", "response to virus", "type I interferon signaling pathway", "negative regulation of viral genome replication", "innate immune response", and "RNA-binding". Conclusion: After PEG-IFN treatment, a certain mRNA expression profile was observed in patients with CHB, providing further mechanistic insights into the antiviral effect of this therapy.

10.
Artigo em Inglês | MEDLINE | ID: mdl-39455513

RESUMO

techniques of mitral valve repair has improved in the last decades. Percutaneous approach is now a reliable and safe therapy in those patients with high surgical risk. However, the presence of an implanted prothesis increases the risk of endocarditis. we describe a case of a 75-year-old man with medical history of recurrent cellulitis due to chronic lymphedema, who had percutaneous edge-to-edge mitral valve treatment. After three months he developed fever without any specific symptoms. Emocolture were positive for Staphilococcus lugdunensis. Transesophageal echocardiogram demonstrated a huge vegetation at the level of Edwards Pascal device. Patients was then referred to cardiac surgery for mitral valve replacement with bioprothesis. in patients needing a prothesis implantation the management and treatment of chronic infection is of paramount importance to reduce the risk of prothesis infection procedure. Endocarditis after percutaneous edge-to-edge mitral valve treatment represents a rare but a life-threatening condition.

11.
Artigo em Inglês | MEDLINE | ID: mdl-39475752

RESUMO

Background: The study assessed replicative human immunodeficiency virus-(HIV-) infection and replicative co-infections as well as molecular determinants of reduced susceptibility towards anti-retroviral therapy in a Ghanaian population of known HIV patients and a control group. Methods: Real-time PCRs for HIV-1, HIV-2, hepatitis B virus (HBV) and hepatitis C virus (HCV) were run with serum samples from known Ghanaian HIV-patients (n = 975) and control individuals (n = 105). For 108 individuals, HIV-sequence analysis was performed. Results: Prevalence of replicative HIV-1 infection was 59.8% (583/975) in the known HIV-positive population and 2.9% (3/105) in the controls. Prevalences of replicative HBV-infection were comparable with 3.4% (33/975) in the HIV-positive individuals and 3.8% (4/105) in the controls. HIV-2 and HCV sequences were not recorded. Almost perfect concordance between two compared HIV-1-PCR assays was indicated by Fleiss' Kappa >0.8. Sanger sequencing indicated CRF_02AG, G and A3 as the quantitatively dominating HIV-1 subtypes, a minority of 3.4% CXCR4 tropism and high detection rates of mutations mediating reduced susceptibility towards nucleoside reverse transcriptase inhibitors (71.9%, 64/89), non-nucleoside reverse transcriptase inhibitors (95.5%, 85/89), protease inhibitors (95.9%, 93/97) and integrase inhibitors (22.4%, 22/98). Conclusions: The assessment did not suggest HIV-triggered increased replication of HBV and HCV in the investigated Ghanaian population.

12.
IDCases ; 38: e02100, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39469501

RESUMO

Background: Hepatitis B virus (HBV) infection affects millions worldwide, predominantly targeting the liver, leading to conditions like cirrhosis and hepatocellular cancer. However, HBV can also cause extrahepatic complications, including autoimmune-mediated vasculitis. Small vessel vasculitis, often associated with antineutrophil cytoplasmic antibodies (ANCA), can occur in chronic infections like HBV. Case presentation: A 46-year-old man with chronic hepatitis B presented with high fever, diarrhoea, and painful black discolouration on his nose, fingers, and toes. Lab results revealed anaemia, leukocytosis, elevated inflammatory markers, positive c-ANCA, and HBV PCR positivity. He was diagnosed with c-ANCA-associated small vessel vasculitis secondary to chronic hepatitis B. Treatment with methylprednisolone followed by tapering prednisolone and azathioprine led to significant improvement in his condition. Conclusion: This case highlights the rare occurrence of c-ANCA-associated vasculitis in chronic HBV without typical liver symptoms. ANCA testing may aid in early diagnosis and management of such cases. Further research is needed to explore the underlying immunological mechanisms and refine therapeutic approaches.

13.
ACS Biomater Sci Eng ; 10(10): 6558-6568, 2024 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-39297972

RESUMO

The airway mucus of patients with cystic fibrosis has altered properties, which create a microenvironment primed for chronic infections that are difficult to treat. These complex polymicrobial airway infections and corresponding mammalian-microbe interactions are challenging to model in vitro. Here, we report the development of mucus-like hydrogels with varied compositions and viscoelastic properties reflecting differences between healthy and cystic fibrosis airway mucus. Models of cystic fibrosis and healthy airway microenvironments were created by combining the hydrogels with relevant pathogens, human bronchial epithelial cells, and an antibiotic. Notably, pathogen antibiotic resistance was not solely dependent on the altered properties of the mucus-like hydrogels but was also influenced by culture conditions including microbe species, monomicrobial or polymicrobial culture, and the presence of epithelial cells. Additionally, the cystic fibrosis airway model showed the ability to mimic features characteristic of chronic cystic fibrosis airway infections including sustained polymicrobial growth and increased antibiotic tolerance.


Assuntos
Antibacterianos , Fibrose Cística , Hidrogéis , Muco , Fibrose Cística/microbiologia , Fibrose Cística/tratamento farmacológico , Hidrogéis/química , Humanos , Muco/microbiologia , Muco/metabolismo , Muco/química , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Pseudomonas aeruginosa/efeitos dos fármacos , Células Epiteliais/microbiologia , Modelos Biológicos
14.
Parasit Vectors ; 17(1): 377, 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-39237959

RESUMO

BACKGROUND: Toxoplasma gondii is an intracellular opportunistic pathogenic protozoan that poses serious threats, particularly in immunocompromised individuals. In the absence of a robust prophylactic measure, the mitigation and management of toxoplasmosis present formidable challenges to public health. We recently found that GRA72 plays an important role in parasitophorous vacuole (PV) morphology, growth and virulence of T. gondii. However, whether gra72-deficient strain can be used as a vaccine remains unknown. METHODS: We first examined the attenuated virulence of gra72 gene knockout strain (PruΔgra72) and the parasite load in organs of the infected mice. Subsequently, we evaluated the immune-protective effects of the PruΔgra72 vaccination against challenge with various types of T. gondii tachyzoites and Pru cysts. Furthermore, levels of antibodies and cytokines induced by PruΔgra72 vaccination were examined. Statistical analysis was conducted by Student's t-test or Mantel-Cox log-rank test based on data obtained from three independent experiments with GraphPad Prism 8.0. RESULTS: We found that PruΔgra72 strain exhibited a significantly attenuated virulence even at the highest dose of 5 × 107 tachyzoites in Kunming mice model. The significant decrease of brain cyst burden and parasite load in the organs of the PruΔgra72-infected mice suggested its potentiality as a live-attenuated vaccine. Hence, we explored the protective immunity of PruΔgra72 vaccination against toxoplasmosis. Results showed that vaccination with 5 × 106 PruΔgra72 tachyzoites triggered a strong and sustained Th1-biased immune response, marked by significantly increased levels of anti-T. gondii IgG antibodies, and significantly higher levels of Th1 type cytokines (IL-2, IL-12 and IFN-γ) compared to that of Th2 type (IL-4 and IL-10). Vaccination with 5 × 106 PruΔgra72 tachyzoites in mice conferred long-term protection against T. gondii infection by less virulent tachyzoites (ToxoDB#9 PYS and Pru strains) and Pru cysts, provided partial protection against acute infection by high virulent Type I RH tachyzoites and significantly decreased brain cyst burden of chronically infected mice. CONCLUSIONS: The avirulent PruΔgra72 induced strong protective immunity against acute and chronic T. gondii infection and is a promising candidate for developing a safe and effective live-attenuated vaccine against T. gondii infection.


Assuntos
Anticorpos Antiprotozoários , Proteínas de Protozoários , Vacinas Protozoárias , Toxoplasma , Toxoplasmose Animal , Vacinas Atenuadas , Animais , Toxoplasma/imunologia , Toxoplasma/genética , Camundongos , Vacinas Protozoárias/imunologia , Vacinas Protozoárias/administração & dosagem , Vacinas Atenuadas/imunologia , Vacinas Atenuadas/administração & dosagem , Proteínas de Protozoários/imunologia , Proteínas de Protozoários/genética , Anticorpos Antiprotozoários/sangue , Feminino , Toxoplasmose Animal/prevenção & controle , Toxoplasmose Animal/imunologia , Citocinas/metabolismo , Virulência , Carga Parasitária , Modelos Animais de Doenças , Doença Crônica , Toxoplasmose/prevenção & controle , Toxoplasmose/imunologia , Toxoplasmose/parasitologia
15.
Viruses ; 16(9)2024 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-39339862

RESUMO

Elimination of hepatitis C virus (HCV) without the need for medical intervention, known as spontaneous clearance (SC), occurs at a significantly lower rate than in the case of hepatitis B virus infection and only in selected individuals, such as reportedly in Keith Richards, a guitarist of The Rolling Stones. The present paper provides an updated narrative review of the research devoted to the phenomenon in order to identify and discuss the demographic, lifestyle-related, clinical, viral genotype-related, and host genetic factors underpinning the SC occurrence. The body of evidence indicates that the likelihood of SC is decreased in older individuals, men, Black people, HIV-coinfected subjects, and intravenous drug and alcohol users. In turn, HBV coinfection and specific polymorphism of the genes encoding interferon lambda 3 (particularly at rs8099917) and interferon lambda 4 (particularly at rs12979860) and HLA genes increase the odds of SC. Numerous other host-specific genetic factors could be implicated in SC, but the evidence is limited only to certain ethnic groups and often does not account for confounding variables. SC of HCV infection is a complex process arising from a combination of various factors, though a genetic component may play a leading role in some cases. Understanding factors influencing the likelihood of this phenomenon justifies better surveillance of high-risk groups, decreasing health inequities in particular ethnic groups, and may guide the development of a prophylactic vaccine, which at present is not available, or novel therapeutic strategies. Further research is needed to elucidate the exact mechanisms underlying SC and to explore potential interventions that could enhance this natural antiviral response.


Assuntos
Hepacivirus , Hepatite C , Humanos , Hepacivirus/genética , Hepatite C/virologia , Hepatite C/genética , Remissão Espontânea , Genótipo , Masculino , Coinfecção/virologia
16.
mBio ; 15(9): e0064124, 2024 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-39150246

RESUMO

Toxoplasma gondii bradyzoites play a critical role in pathology due to their long-term persistence in intermediate hosts and their potential to reactivate, resulting in severe diseases in immunocompromised individuals. Currently, there is no effective treatment for eliminating bradyzoites. Hence, better in vitro models of T. gondii bradyzoite development would facilitate identification of therapeutic targets for bradyzoites. Herein, we characterized a natural isolate of T. gondii, called Tg68, which showed slower in vitro replication of tachyzoites, and permissive bradyzoite development under stress conditions in vitro. Transcriptional analysis revealed constitutive expression in Tg68 tachyzoites of the key regulators of bradyzoite development including BFD1, BFD2, and several AP2 factors. Consistent with this finding, Tg68 tachyzoites expressed high levels of bradyzoite-specific genes including BAG1, ENO1, and LDH2. Moreover, after stress-induced differentiation, Tg68 bradyzoites exhibited gene expression profiles of mature bradyzoites, even at early time points. These data suggest that Tg68 tachyzoites exist in a pre-bradyzoite stage primed to readily develop into mature bradyzoites under stress conditions in vitro. Tg68 presents a novel model for differentiation in vitro that will serve as a useful tool for the investigation of bradyzoite biology and the development of therapeutics. IMPORTANCE: Toxoplasma gondii is a widespread protozoan that chronically infects ~30% of the world's population. T. gondii can differentiate between the fast-growing life stage that causes acute infection and the slow-growing stage that persists in the host for extended periods of time. The slow-growing stage cannot be eliminated by the host immune response or currently known antiparasitic drugs. Studies on the slow-growing stage have been limited due to the limitations of in vivo experiments and the challenges of in vitro manipulation. Here, we characterize a natural isolate of T. gondii, which constitutively expresses factors that drive development and that is permissive to convert to the slow-growing stage under stress conditions in vitro. The strain presents a novel in vitro model for studying the chronic phase of toxoplasmosis and identifying new therapeutic treatments for chronic infections.


Assuntos
Proteínas de Protozoários , Toxoplasma , Fatores de Transcrição , Toxoplasma/genética , Toxoplasma/crescimento & desenvolvimento , Toxoplasma/metabolismo , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Regulação para Cima , Animais , Camundongos , Estágios do Ciclo de Vida , Perfilação da Expressão Gênica , Humanos , Toxoplasmose/parasitologia , Fibroblastos/parasitologia
17.
Virus Genes ; 2024 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-39196289

RESUMO

Hepatitis B virus (HBV) infection remains a significant global health challenge, with chronic HBV leading to severe liver diseases, including cirrhosis and hepatocellular carcinoma. Current treatments often fail to eradicate the virus, highlighting the need for innovative therapeutic strategies. The CRISPR/Cas9 system has emerged as a dynamic tool for precise genome editing and presents a promising approach to targeting and eliminating HBV infection. This review provides a comprehensive overview of the advances, challenges, and delivery strategies associated with CRISPR/Cas9-based therapies for HBV. We begin by elucidating the mechanism of the CRISPR/Cas9 system and then explore HBV pathogenesis, focusing on the role of covalently closed circular DNA (cccDNA) and integrated HBV DNA in maintaining chronic infection. CRISPR/Cas9 can disrupt these key viral reservoirs, which are critical for persistent HBV replication and associated liver damage. The application of CRISPR/Cas9 in HBV treatment faces significant challenges, such as off-target effects, delivery efficiency, and immune responses. These challenges are addressed by examining current approaches to enhance the specificity, safety, and efficacy of CRISPR/Cas9. A future perspective on the development and clinical translation of CRISPR/Cas9 therapies for HBV is provided, emphasizing the requirement for further research to improve delivery methods and ensure durable safety and effectiveness. This review underscores the transformative potential of CRISPR/Cas9 in combating HBV and sets the stage for future breakthroughs in the field.

18.
Animals (Basel) ; 14(16)2024 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-39199857

RESUMO

In ovine populations, the enzootic nature of Chlamydia abortus (C. abortus) is attributed to its capacity to establish persistent intracellular infections, which necessitate a cellular immune response mediated by interferon-gamma (IFN-γ) for effective resolution. In both natural hosts and murine models, interleukin-10 (IL-10) has been demonstrated to modulate the cellular immune response crucial for the eradication of C. abortus. During gestation, it has also been shown to play a role in preventing inflammatory damage to gestational tissues and foetal loss through the downregulation of pro-inflammatory cytokines. This paradigm can be key for events leading to a protective response towards an infectious abortion. Previous research successfully established a mouse model of chronic C. abortus infection using transgenic mice overexpressing IL-10 (IL-10tg), simulating the dynamics of chronic infection observed in non-pregnant natural host. This study aims to evaluate the efficacy of an experimental inactivated vaccine against C. abortus and to elucidate the immune mechanisms involved in protection during chronic infection using this model. Transgenic and wild-type (WT) control mice were immunized and subsequently challenged with C. abortus. Vaccine effectiveness and immune response were assessed via immunohistochemistry and cytokine serum levels over a 28-day period. Morbidity, measured by daily weight loss, was more pronounced in non-vaccinated transgenic IL-10 mice, though no mortality was observed in any group. Vaccinated control mice eliminated the bacterial infection by day 9 post-infection (p.i.), whereas presence of bacteria was noted in vaccinated transgenic IL-10 mice until day 28 p.i. Vaccination induced an early post-infection increase in IFN-γ production, but did not alter IL-10 production in transgenic mice. Histological analysis indicated suboptimal recruitment of inflammatory cells in vaccinated transgenic IL-10 mice compared to WT controls. In summary, the findings suggest that IL-10 overexpression in transgenic mice diminishes the protective efficacy of vaccination, confirming that this model can be useful for validating the efficacy of vaccines against intracellular pathogens such as C. abortus that require robust cell-mediated immunity.

19.
mSphere ; 9(9): e0032224, 2024 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-39189782

RESUMO

Expansion microscopy (ExM) is an innovative approach to achieve super-resolution images without using super-resolution microscopes, based on the physical expansion of the sample. The advent of ExM has unlocked the detail of super-resolution images for a broader scientific circle, lowering the cost and entry skill requirements for the field. One of its branches, ultrastructure expansion microscopy (U-ExM), has become popular among research groups studying apicomplexan parasites, including the acute stage of Toxoplasma gondii infection. Here, we show that the chronic cyst-forming stage of Toxoplasma, however, resists U-ExM expansion, impeding precise protein localization. We then solve the in vitro cyst's resistance to denaturation required for successful U-ExM. As the cyst's main structural protein CST1 contains a mucin domain, we added an enzymatic digestion step using the pan-mucinase StcE prior to the expansion protocol. This allowed full expansion of the cysts in fibroblasts and primary neuronal cell culture without disrupting immunofluorescence analysis of parasite proteins. Using StcE-enhanced U-ExM, we clarified the localization of the GRA2 protein, which is important for establishing a normal cyst, observing GRA2 granules spanning across the CST1 cyst wall. The StcE-U-ExM protocol allows accurate pinpointing of proteins in the bradyzoite cyst, which will greatly facilitate investigation of the underlying biology of cyst formation and its vulnerabilities. IMPORTANCE: Toxoplasma gondii is an intracellular parasite capable of establishing long-term chronic infection in nearly all warm-blooded animals. During the chronic stage, parasites encapsulate to form cysts predominantly in neurons and skeletal muscle. Current anti-Toxoplasma drugs do not eradicate chronic parasites, leaving a reservoir of infection. The cyst is critical for disease transmission and pathology, yet it is harder to study, with the function of many chronic-stage proteins still unknown. Ultrastructure expansion microscopy, a new method to overcome the light microscopy's diffraction limit by physically expanding the sample, allowed in-depth studies of acute Toxoplasma infection. We show that Toxoplasma cysts resist expansion using standard protocol, but an additional enzymatic digestion with the mucinase StcE allows full expansion. This protocol offers new avenues for examining the chronic stage, including precise spatial organization of cyst-specific proteins, linking these locations to morphological structures, and detailed investigations of components of the durable cyst wall.


Assuntos
Fibroblastos , Toxoplasma , Toxoplasma/ultraestrutura , Animais , Fibroblastos/parasitologia , Camundongos , Proteínas de Protozoários/metabolismo , Microscopia/métodos , Toxoplasmose/parasitologia , Neurônios/parasitologia
20.
EBioMedicine ; 107: 105273, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39146693

RESUMO

BACKGROUND: De novo amino acid substitutions (DNS) frequently emerge among immunocompromised patients with chronic SARS-CoV-2 infection. While previous studies have reported these DNS, their significance has not been systematically studied. METHODS: We performed a review of DNS that emerged during chronic SARS-CoV-2 infection. We searched PubMed until June 2023 using the keywords "(SARS-CoV-2 or COVID-19) and (mutation or sequencing) and ((prolonged infection) or (chronic infection) or (long term))". We included patients with chronic SARS-CoV-2 infection who had SARS-CoV-2 sequencing performed for at least 3 time points over at least 60 days. We also included 4 additional SARS-CoV-2 patients with chronic infection of our hospital not reported previously. We determined recurrent DNS that has appeared in multiple patients and determined the significance of these mutations among epidemiologically-significant variants. FINDINGS: A total of 34 cases were analyzed, including 30 that were published previously and 4 from our hospital. Twenty two DNS appeared in ≥3 patients, with 14 (64%) belonging to lineage-defining mutations (LDMs) of epidemiologically-significant variants and 10 (45%) emerging among chronically-infected patients before the appearance of the corresponding variant. Notably, nsp9-T35I substitution (Orf1a T4175I) emerged in all three patients with BA.2.2 infection in 2022 before the appearance of Variants of Interest that carry nsp9-T35I as LDM (EG.5 and BA.2.86/JN.1). Structural analysis suggests that nsp9-T35I substitution may affect nsp9-nsp12 interaction, which could be critical for the function of the replication and transcription complex. INTERPRETATION: DNS that emerges recurrently in different chronically-infected patients may be used as a marker for potential epidemiologically-significant variants. FUNDING: Theme-Based Research Scheme [T11/709/21-N] of the Research Grants Council (See acknowledgements for full list).


Assuntos
Substituição de Aminoácidos , COVID-19 , SARS-CoV-2 , Humanos , COVID-19/genética , COVID-19/virologia , COVID-19/epidemiologia , SARS-CoV-2/genética , Doença Crônica , Mutação , Feminino , Masculino , Pessoa de Meia-Idade , Idoso
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