Sebastián Valentina P, Moreno-Tapia Daniela, Melo-González Felipe, Hernández-Cáceres María P, Salazar Geraldyne A, Pardo-Roa Catalina, Farías Mónica A, Vallejos Omar P, Schultz Bárbara M, Morselli Eugenia, Álvarez-Lobos Manuel M, González Pablo A, Kalergis Alexis M, Bueno Susan M
Millenium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile.
Laboratory of Autophagy and Metabolism, Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile.
Antioxidants (Basel). 2022 May 24;11(6):1040. doi: 10.3390/antiox11061040.
An important virulence trait of serovar Typhimurium ( Typhimurium) is the ability to avoid the host immune response, generating systemic and persistent infections. Host cells play a crucial role in bacterial clearance by expressing the enzyme heme oxygenase 1 (Hmox1), which catalyzes the degradation of heme groups into Fe, biliverdin, and carbon monoxide (CO). The role of Hmox1 activity during Typhimurium infection is not clear and previous studies have shown contradictory results. We evaluated the effect of pharmacologic modulation of Hmox1 in a mouse model of acute and persistent Typhimurium infection by administering the Hmox1 activity inductor cobalt protoporphyrin-IX (CoPP) or inhibitor tin protoporphyrin-IX (SnPP) before infection. To evaluate the molecular mechanism involved, we measured the colocalization of Typhimurium and autophagosome and lysosomal markers in macrophages. Administering CoPP reduced the bacterial burden in organs of mice 5 days post-infection, while SnPP-treated mice showed bacterial loads similar to vehicle-treated mice. Furthermore, CoPP reduced bacterial loads when administered after infection in macrophages in vitro and in a persistent infection model of Typhimurium in vivo, while tin protoporphyrin-IX (SnPP) treatment resulted in a bacterial burden similar to vehicle-treated controls. However, we did not observe significant differences in co-localization of green fluorescent protein (GFP)-labeled Typhimurium with the autophagic vesicles marker microtubule-associated protein 1A/1B-light chain 3 (LC3) and the lysosomal marker lysosomal-associated membrane protein 1 (LAMP-1) in macrophages treated with CoPP. Our results suggest that CoPP can enhance antimicrobial activity in response to infection, reducing bacterial dissemination and persistence in mice, in a CO and autophagy- independent manner.
鼠伤寒血清型（鼠伤寒）的一个重要毒力特征是能够逃避宿主免疫反应，引发全身性和持续性感染。宿主细胞通过表达血红素加氧酶1（Hmox1）在细菌清除中发挥关键作用，该酶催化血红素基团降解为铁、胆绿素和一氧化碳（CO）。Hmox1活性在鼠伤寒感染期间的作用尚不清楚，先前的研究结果相互矛盾。我们通过在感染前给予Hmox1活性诱导剂钴原卟啉-IX（CoPP）或抑制剂锡原卟啉-IX（SnPP），评估了Hmox1的药物调节在急性和持续性鼠伤寒感染小鼠模型中的作用。为了评估其中涉及的分子机制，我们测量了鼠伤寒与巨噬细胞中自噬体和溶酶体标志物的共定位。感染后5天，给予CoPP可降低小鼠器官中的细菌载量，而经SnPP处理的小鼠的细菌载量与经载体处理的小鼠相似。此外，在体外巨噬细胞感染后以及在鼠伤寒的体内持续性感染模型中给予CoPP可降低细菌载量，而锡原卟啉-IX（SnPP）处理导致的细菌载量与经载体处理的对照组相似。然而，在用CoPP处理的巨噬细胞中，我们未观察到绿色荧光蛋白（GFP）标记的鼠伤寒与自噬小泡标志物微管相关蛋白1A/1B轻链3（LC3）和溶酶体标志物溶酶体相关膜蛋白1（LAMP-1）的共定位有显著差异。我们的结果表明，CoPP可以增强对感染的抗菌活性，以一种不依赖CO和自噬的方式减少小鼠体内细菌的传播和持续性。
