Scholarlink

<p>The high mortality associated with tuberculosis (TB), alongside the lack of efficient therapeutics against emerging multidrug-resistant <i>Mycobacterium tuberculosis</i> (<i>Mtb</i>) strains, emphasizes the need for novel antitubercular targets. Mycobacterial peptidoglycan (PG), displaying characteristic modifications comprising the amidation of D-<i>iso</i>-glutamate (D-<i>i</i>Glu) and the <i>N</i>-glycolylation of muramic acid, is therefore a promising therapeutic target. The genes encoding the enzymes mediating these modifications (<i>murT</i>/<i>gatD</i> and <i>namH</i>) were silenced in <i>Mtb</i> using CRISPR interference (CRISPRi) to investigate their impact on β-lactam susceptibility and host immune responses. First, qRT-PCR confirmed successful target mRNA knockdown and phenotyping assays corroborated the essentiality of D-<i>i</i>Glu amidation for mycobacterial growth, in contrast to muramic acid <i>N</i>-glycolylation. The susceptibility assays demonstrated that both PG modifications promote β-lactam resistance. Indeed, we observed reductions in the minimum fractional inhibitory concentration index (FICI<sub>min</sub>) value for AMX/MEM + CLA and EMB combinations following the depletion of both PG modifications. Furthermore, D-<i>i</i>Glu amidation was found to promote <i>Mtb</i> fitness within THP-1-derived macrophages 6&#xa0;days post-infection. Infection with MurT/GatD-depleted <i>Mtb</i> was associated with increased IL-1β and decreased IL-10, whereas NamH depletion was linked to increased IL-1β and IL-10 levels. Altogether, our findings unveiled the potential of targeting these PG modifications for the development of innovative therapeutic regimens against TB.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Genetic interference of distinctive Mycobacterium tuberculosis peptidoglycan modifications enhances β-lactam susceptibility and reveals expression-sensitive host immune dynamics

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年6月23日

查看全文
  • Cátia Silveiro,
  • Mariana Marques,
  • Francisco Olivença,
  • David Pires,
  • Elsa Anes,
  • Maria João Catalão

摘要

The high mortality associated with tuberculosis (TB), alongside the lack of efficient therapeutics against emerging multidrug-resistant Mycobacterium tuberculosis (Mtb) strains, emphasizes the need for novel antitubercular targets. Mycobacterial peptidoglycan (PG), displaying characteristic modifications comprising the amidation of D-iso-glutamate (D-iGlu) and the N-glycolylation of muramic acid, is therefore a promising therapeutic target. The genes encoding the enzymes mediating these modifications (murT/gatD and namH) were silenced in Mtb using CRISPR interference (CRISPRi) to investigate their impact on β-lactam susceptibility and host immune responses. First, qRT-PCR confirmed successful target mRNA knockdown and phenotyping assays corroborated the essentiality of D-iGlu amidation for mycobacterial growth, in contrast to muramic acid N-glycolylation. The susceptibility assays demonstrated that both PG modifications promote β-lactam resistance. Indeed, we observed reductions in the minimum fractional inhibitory concentration index (FICImin) value for AMX/MEM + CLA and EMB combinations following the depletion of both PG modifications. Furthermore, D-iGlu amidation was found to promote Mtb fitness within THP-1-derived macrophages 6 days post-infection. Infection with MurT/GatD-depleted Mtb was associated with increased IL-1β and decreased IL-10, whereas NamH depletion was linked to increased IL-1β and IL-10 levels. Altogether, our findings unveiled the potential of targeting these PG modifications for the development of innovative therapeutic regimens against TB.