Background <p>Doxorubicin (DOX) cardiotoxicity is a major complication of cancer therapy and involves macrophage-driven inflammation and myocardial remodeling. The macrophage surface protein Mac-2 (galectin-3) is upregulated in cardiac injury, but its role in regulating macrophage function and downstream injury pathways remains undefined.</p> Methods <p>We used CRISPR/Cas9-engineered Mac-2-null macrophages to evaluate chemotaxis, cytokine gene expression, and lysosomal stress signaling in vitro. To examine paracrine injury mechanisms, we performed co-culture assays with cardiomyocytes and fibroblasts. In vivo, we studied homozygous Mac-2-mutant mice and used CD45.1/CD45.2 bone marrow transplantation with lineage tracking to define hematopoietic versus stromal contributions to DOX-induced inflammation, apoptosis, fibrosis, and systolic dysfunction.</p> Results <p>Doxorubicin induced Mac-2 and inflammatory transcripts (<i>Il6</i>,<i> Tnf</i>,<i> Ccl2</i>) in wild-type macrophages, whereas Mac-2 knockout reduced DOX uptake, chemotaxis, and cytokine induction. In co-culture, DOX-treated WT macrophages increased caspase-3/7 activity in cardiomyocytes and phospho-TFEB in fibroblasts, both attenuated with Mac-2 deletion. In vivo, Mac-2-null mice exhibited less cardiac inflammation, apoptosis, and fibrosis with preserved systolic function and reduced mortality. Bone marrow transplantation demonstrated that hematopoietic Mac-2 suppressed cardiac <i>Tfeb</i> and upregulated <i>Sqstm1</i> and <i>Tgfb1</i>, enhancing inflammatory and apoptotic responses, whereas Mac-2-deficient marrow restored <i>Tfeb</i>, limited <i>Sqstm1</i>/<i>Tgfb1</i>, and protected cardiac function.</p> Conclusions <p>Mac-2 promotes DOX-induced cardiac injury by facilitating inflammatory activation in macrophages, driving fibroblast lysosomal stress via TFEB and SQSTM1, and augmenting caspase-3–associated apoptosis in cardiomyocytes. Loss of Mac-2 in hematopoietic cells reduces inflammation, fibrosis, and systolic dysfunction in vivo.</p>

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Macrophage surface protein Mac-2 mediates inflammatory and stromal stress pathways in doxorubicin-induced cardiac injury

  • Swati D. Sonkawade,
  • Lee D. Chavez,
  • Shirley Xu,
  • Xiaoyi Ma,
  • Sarmila Nepali,
  • Steven E. Lipshultz,
  • Saraswati Pokharel,
  • Umesh C. Sharma

摘要

Background

Doxorubicin (DOX) cardiotoxicity is a major complication of cancer therapy and involves macrophage-driven inflammation and myocardial remodeling. The macrophage surface protein Mac-2 (galectin-3) is upregulated in cardiac injury, but its role in regulating macrophage function and downstream injury pathways remains undefined.

Methods

We used CRISPR/Cas9-engineered Mac-2-null macrophages to evaluate chemotaxis, cytokine gene expression, and lysosomal stress signaling in vitro. To examine paracrine injury mechanisms, we performed co-culture assays with cardiomyocytes and fibroblasts. In vivo, we studied homozygous Mac-2-mutant mice and used CD45.1/CD45.2 bone marrow transplantation with lineage tracking to define hematopoietic versus stromal contributions to DOX-induced inflammation, apoptosis, fibrosis, and systolic dysfunction.

Results

Doxorubicin induced Mac-2 and inflammatory transcripts (Il6, Tnf, Ccl2) in wild-type macrophages, whereas Mac-2 knockout reduced DOX uptake, chemotaxis, and cytokine induction. In co-culture, DOX-treated WT macrophages increased caspase-3/7 activity in cardiomyocytes and phospho-TFEB in fibroblasts, both attenuated with Mac-2 deletion. In vivo, Mac-2-null mice exhibited less cardiac inflammation, apoptosis, and fibrosis with preserved systolic function and reduced mortality. Bone marrow transplantation demonstrated that hematopoietic Mac-2 suppressed cardiac Tfeb and upregulated Sqstm1 and Tgfb1, enhancing inflammatory and apoptotic responses, whereas Mac-2-deficient marrow restored Tfeb, limited Sqstm1/Tgfb1, and protected cardiac function.

Conclusions

Mac-2 promotes DOX-induced cardiac injury by facilitating inflammatory activation in macrophages, driving fibroblast lysosomal stress via TFEB and SQSTM1, and augmenting caspase-3–associated apoptosis in cardiomyocytes. Loss of Mac-2 in hematopoietic cells reduces inflammation, fibrosis, and systolic dysfunction in vivo.