Dendritic cells are crucial for bridging innate and adaptive immunity. Cryptococcosis, caused by Cryptococcus neoformans and Cryptococcus gattii, is responsible for >15% of AIDS-related deaths. A recent study by Xu et al. showed that Batf3-dependent conventional type 1 dendritic (cDC1) cells are key players in generating IFNγ+ CD4+ T cell and fungicidal lung and brain tissue-resident responses during murine cryptococcosis, contributing to fungal clearance in the lungs and brain of mice (J. Xu, R. Hissong, R. Bareis, A. Creech, et al., mBio 15:e02853-23, 2024, https://doi.org/10.1128/mbio.02853-23). However, despite their critical role, the depletion of Batf3-dependent cDC1 cells did not significantly alter overall mouse survival or disease progression, highlighting the complex immune regulation required to survive cryptococcal infection and the need for further research in medical mycology.

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While type I conventional dendritic cells (cDC1s) are vital for generating adaptive immunity against intracellular pathogens and tumors, their role in defense against fungal pathogen Cryptococcus neoformans remains unclear. We investigated the role of the cDC1 subset in a fungus-restricting mouse model of cryptococcal infection. The cDC1 subset displayed a unique transcriptional signature with highly upregulated T-cell recruitment, polarization, and activation pathways compared to other DC subsets. Using Batf3-/- mice, which lack the cDC1 population, our results support that Batf3-dependent cDC1s are pivotal for the development of the effective immune response against cryptococcal infection, particularly within the lung and brain. Deficiency in Batf3 cDC1 led to diminished CD4 accumulation and decreased IFNγ production across multiple organs, supporting that cDC1s are a major driver of potent Th1 responses during cryptococcal infection. Consistently, mice lacking Batf3-cDC1 demonstrated markedly diminished fungicidal activity and weaker containment of the fungal pathogen. In conclusion, Batf3-dependent cDC1 can function as a linchpin in mounting Th1 response, ensuring effective fungal control during cryptococcal infection. Harnessing cDC1 pathways may present a promising strategy for interventions against this pathogen.IMPORTANCECryptococcus neoformans causes severe meningoencephalitis, accounting for an estimated 200,000 deaths each year. Central to mounting an effective defense against these infections is T-cell-mediated immunity, which is orchestrated by dendritic cells (DCs). The knowledge about the role of specific DC subsets in shaping anti-cryptococcal immunity is limited. Here, we demonstrate that Batf3 cDC1s are important drivers of protective Th1 CD4 T-cell responses required for clearance of cryptococcal infection. Deficiency of Batf3 cDC1 in the infected mice leads to significantly reduced Th1 response and exacerbated fungal growth to the point where depleting the remaining CD4 T cells no longer affects fungal burden. Unveiling this pivotal role of cDC1 in antifungal defense is likely to be important for the development of vaccines and therapies against life-threatening fungal pathogens.

OBJECTIVE: Despite considerable improvement in therapeutic approaches to chronic myeloid leukemia (CML) treatment, this malignancy is considered incurable due to resistance. However, investigating the molecular mechanism of CML may give rise to the development of extremely efficient targeted therapies that improve the prognosis of patients. Basic leucine zipper transcription factor ATF-like3 (BATF3), as transcription factor, is considered a key regulator of cellular activities and its function has been evaluated in tumor development and growth in several cancer types. This study aimed to evaluate the potential of the cellular impact of siRNA-mediated downregulation of BATF3 on CML cancer cells through cell proliferation, induction of apoptosis, and cell cycle distribution.
METHODS: The transfection of BATF3 siRNA to K562 CML cells was performed by electroporation device. To measure cellular viability and apoptosis, MTT assay and Annexin V/PI staining were carried out, respectively. Also, cell cycle assay and flow cytometry instrument were applied to assess cell cycle distribution of K562 cells. For more validation, mRNA expression of correlated genes was relatively evaluated by quantitative real-time polymerase chain reaction (qRT-PCR).
RESULTS: The data indicated that siRNA-mediated BATF3 inactivating severely promoted the cell apoptosis. Also, the targeted therapy led to high expression of Caspase-3 gene and Bax/Bcl-2 ratio. Silenced BATF3 also induced cell cycle arrest in phase sub-G1 compared to control. Finally, a noticeable decrement was obtained in c-Myc gene expression through suppression of BATF3 in CML cells.
CONCLUSIONS: The findings of this research illustrated the suppression of BATF3 as an effective targeted therapy strategy for CML.

OBJECTIVE: Gastric cancer is one of the most common and deadly cancers worldwide. Basic leucine zipper transcription factor ATF-like 3 (BATF3) plays a key role in tumor immunity. However, the function of BATF3 in gastric cancer remains unclear. Here, we demonstrated BATF3 positively regulated proliferation and radioresistance of gastric cancer cells by regulating S1PR1/STAT3 pathway.
METHODS: The RNA-seq analyzed the gene expression by UALCAN web portal and Tumor Immune Estimation Resource. RT-qPCR and western blot was performed to verify BATF3 expression in gastric cancer cells. The assays of CCK-8, EdU incorporation and colony formation were used to analyze cell proliferation, and radioresistance in AGS and MKN45 cells. Flow cytometry was used to detect the cell apoptosis of AGS and MKN45 in treatment with si-BATF3 or radiation. Finally, western blot was performed to measure the expression of cell apoptosis-related modules including Bax, cleaved-caspase3, cleaved-PARP and assess the regulation of S1PR1/STAT3 pathway.
RESULTS: BATF3 expression was upregulated in gastric cancer cells. Knockdown of BATF3 suppressed proliferation, radioresistance but promoted the radiation-induced apoptosis of gastric cancer cells through positively regulating S1PR1 expression and STAT3 phosphorylation.
CONCLUSIONS: Knockdown of BATF3 inhibits gastric cancer cell growth and radioresistance via S1PR1/STAT3 pathway. BATF3 would become a potential diagnostic indicator for gastric cancer and target of therapeutic treatment.

The intestinal immune system and microbiota are emerging as important contributors to the development of metabolic syndrome, but the role of intestinal dendritic cells (DCs) in this context is incompletely understood. BATF3 is a transcription factor essential in the development of mucosal conventional DCs type 1 (cDC1). We show that Batf3-/- mice developed metabolic syndrome and have altered localization of tight junction proteins in intestinal epithelial cells leading to increased intestinal permeability. Treatment with the glycolysis inhibitor 2-deoxy-D-glucose reduced intestinal inflammation and restored barrier function in obese Batf3-/- mice. High-fat diet further enhanced the metabolic phenotype and susceptibility to dextran sulfate sodium colitis in Batf3-/- mice. Antibiotic treatment of Batf3-/- mice prevented metabolic syndrome and impaired intestinal barrier function. Batf3-/- mice have altered IgA-coating of fecal bacteria and displayed microbial dysbiosis marked by decreased obesity protective Akkermansia muciniphila, and Bifidobacterium. Thus, BATF3 protects against metabolic syndrome and preserves intestinal epithelial barrier by maintaining beneficial microbiota.

Long noncoding RNA (lncRNA) plays a critical role in tumorigenesis. How lncRNA regulates laryngeal squamous cell carcinoma (LSCC) progression remains poorly understood. In the present study, we found that LINC01638 was highly expressed in LSCC tissues. And LINC01638 expression was positively correlated with clinical stage and lymph node metastasis. Patients with LINC01638 high expression displayed a low survival rate. Results from CCK8, colony formation, and transwell assays showed that LINC01638 knockdown suppressed the proliferation, migration and invasion of LSCC cells in vitro. Animal experiments indicated that LINC01638 silencing attenuated tumor growth in vivo. In terms of mechanism, LINC01638 was found to sponge miR-523-5p and promote BATF3 expression. In summary, our results demonstrated that LINC01638/miR-523-5p/BATF3 axis plays a crucial function in initiating LSCC development and may be a potential target for tumor therapy.

Unveiling the protective immune response to visceral leishmaniasis is critical for a rational design of vaccines aimed at reducing the impact caused by this fatal, if left untreated, vector-borne disease. In this study we sought to determine the role of the basic leucine zipper transcription factor ATF-like 3 (Batf3) in the evolution of infection with Leishmania infantum, the causative agent of human visceral leishmaniasis in the Mediterranean Basin and Latin America. For that, Batf3-deficient mice in C57BL/6 background were infected with an L. infantum strain expressing the luciferase gene. Bioluminescent imaging, as well as in vitro parasite titration, demonstrated that Batf3-deficient mice were unable to control hepatic parasitosis as opposed to wild-type C57BL/6 mice. The impaired microbicide capacities of L. infantum-infected macrophages from Batf3-deficient mice mainly correlated with a reduction of parasite-specific IFN-γ production. Our results reinforce the implication of Batf3 in the generation of type 1 immunity against infectious diseases.

While immune responses have been rigorously examined after intravenous Listeria monocytogenes (Lm) infection, less is understood about its dissemination from the intestines or the induction of adaptive immunity after more physiologic models of foodborne infection. Consequently, this study focused on early events in the intestinal mucosa and draining mesenteric lymph nodes (MLN) using foodborne infection of mice with Lm modified to invade murine intestinal epithelium (InlAM Lm). InlAM Lm trafficked intracellularly from the intestines to the MLN and were associated with Batf3-independent dendritic cells (DC) in the lymphatics. Consistent with this, InlAM Lm initially disseminated from the gut to the MLN normally in Batf3 -/- mice. Activated migratory DC accumulated in the MLN by 3 days post-infection and surrounded foci of InlAM Lm. At this time Batf3 -/- mice displayed reduced InlAM Lm burdens, implicating cDC1 in maximal bacterial accumulation in the MLN. Batf3 -/- mice also exhibited profound defects in the induction and gut-homing of InlAM Lm-specific effector CD8 T cells. Restoration of pathogen burden did not rescue antigen-specific CD8 T cell responses in Batf3 -/- mice, indicating a critical role for Batf3 in generating anti-InlAM Lm immunity following foodborne infection. Collectively, these data suggest that DC play diverse, dynamic roles in the early events following foodborne InlAM Lm infection and in driving the establishment of intestinal Lm-specific effector T cells.

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