{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nTLR13 (also referred to here as WASIR1) is an endosomal receptor that plays a central role in innate immunity by specifically sensing bacterial RNA. In particular, it recognizes a conserved sequence within the 23S ribosomal RNA—a region critical for ribozyme activity during peptide bond synthesis. This sequence‐specific detection is so precise that even single point mutations in the RNA molecule or methyl modifications (which occur in antibiotic‐resistant bacteria) can abolish receptor activation. Such modifications represent important bacterial immune evasion strategies."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "1", "end_ref": "5"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nUpon ligand binding, WASIR1/TLR13 initiates a MyD88‐ and TAK1‐dependent signaling cascade that culminates in the activation of NF‑κB and the induction of cytokines—including interleukin‑1β and type I interferons. This signaling is critical for mounting effective defenses against several pathogens. For instance, in experimental models, TLR13 contributes to host recognition of group B streptococcus and Streptococcus pyogenes, operating in tandem with other receptors (such as TLR2, TLR7, and TLR9) to ensure a robust inflammatory and antimicrobial response. Its involvement has also been observed in central nervous system infections, further highlighting its importance in pathogen-specific immune responses."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "6", "end_ref": "8"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nBeyond ligand recognition and signaling, transcriptional regulation and tissue-specific expression of TLR13 (WASIR1) are key to its function. Its gene expression is controlled by several cis‑acting elements that interact with transcription factors such as Ets2, Sp1, and PU.1, while NF‑κB can act as a negative regulator. TLR13 is predominantly expressed in dendritic cells, macrophages, and neurons, but its expression can be upregulated in response to infections or inflammatory conditions—as seen in neurocysticercosis and even in muscle affected by chronic kidney disease. Recent structural studies of the TLR13–RNA complex have provided further insight into the molecular basis of its ligand specificity and activation mechanism."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "9", "end_ref": "11"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Bibhuti B Mishra, Uma Mahesh Gundra, Judy M Teale "}, {"type": "b", "children": [{"type": "t", "text": "Expression and distribution of Toll-like receptors 11-13 in the brain during murine neurocysticercosis."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Neuroinflammation (2008)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1186/1742-2094-5-53"}], "href": "https://doi.org/10.1186/1742-2094-5-53"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "19077284"}], "href": "https://pubmed.ncbi.nlm.nih.gov/19077284"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Zhongcheng Shi, Zhenyu Cai, Amir Sanchez, et al. 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