Senolytic Combination of Dasatinib and Quercetin Alleviates Intestinal Senescence and Inflammation and Modulates the Gut Microbiome in Aged Mice

Abstract

Cellular senescence contributes to age-related disorders including physical dysfunction, disabilities, and mortality caused by tissue inflammation and damage. Senescent cells accumulate in multiple tissues with aging and at etiological sites of multiple chronic disorders. The senolytic drug combination, Dasatinib plus Quercetin (D+Q), is known to reduce senescent cell abundance in aged mice. However, the effects of long-term D+Q treatment on intestinal senescent cell and inflammatory burden and microbiome composition in aged mice remain unknown. Here, we examine the effect of D+Q on senescence (p16Ink4a and p21Cip1) and inflammation (Cxcl1, Il1β, Il6, Mcp1, and Tnfα) markers in small (ileum) and large (caecum and colon) intestine in aged mice (n = 10) compared to age-matched placebo-treated mice (n = 10). Additionally, we examine microbial composition along the intestinal tract in these mice. D+Q-treated mice show significantly lower senescent cell (p16 and p21 expression) and inflammatory (Cxcl1, Il1β, Il6, Mcp1, and Tnfα expression) burden in small and large intestine compared with control mice. Further, we find specific microbial signatures in ileal, cecal, colonic, and fecal regions that are distinctly modulated by D+Q, with modulation being most prominent in small intestine. Further analyses reveal specific correlation of senescence and inflammation markers with specific microbial signatures. Together, these data demonstrate that the senolytic treatment reduces intestinal senescence and inflammation while altering specific microbiota signatures and suggest that the optimized senolytic regimens might improve health via reducing intestinal senescence, inflammation, and microbial dysbiosis in older subjects.

Keywords: Biology of aging; Cellular senescence; Longevity; Microbiome; Microbiota.

Figure 1.

Treatment with senolytic combination, Dasatinib plus Quercetin, reduces intestinal senescence and inflammatory burden in aged mice. mRNA levels of markers of senescence (p16^Ink4a and p21^Cip1) and SASP/inflammation, (Cxcl1, Il1β, Il6, Mcp1, Tnfα, and Lmnb1) in ileum (a), caecum (b), and colon (c) of aged mice treated with the senolytic agent combination, D+Q (OT; n = 5) versus placebo-treated control (OC; n = 5) mice. *p < .05 and **p < .01.

Figure 2.

Treatment with senolytic combination, Dasatinib plus Quercetin, modulates the intestinal microbiota in aged mice. The microbiota composition at the level of major bacterial phyla (a–h), the ratio of gram-positive to gram-negative bacterial taxa (i–l), and the microbiota composition at the level of major bacterial families (m–p) in ileum, caecum, colon, and feces of aged mice treated with the senolytic agent combination, D+Q (OT; n = 10) versus placebo-treated control (OC; n = 10) mice.

Figure 3.

Treatment with senolytic combination, Dasatinib plus Quercetin, induces distinct signatures of microbiota modulation along the intestinal tract in aged mice. Volcano-scatter plots (a–d) and hierarchical clustering heat-map (e) depicting specific changes (log2-fold difference greater than 1 or less than −1) in the proportion of bacterial taxa in ileal, cecal, colonic, and fecal microbiota in aged mice treated with the senolytic agent combination, D+Q (OT; n = 10), compared with placebo-treated control (OC; n = 10) mice.

Figure 4.

Treatment with senolytic combination, Dasatinib plus Quercetin, induces specific changes in the microbiota along the intestinal tract in aged mice. Bar graphs depicting distinct arrays of changes (log2-fold difference more than 1 or less than −1) in the proportion of bacterial taxa in ileal (a), cecal (b), colonic (c), and fecal (d) microbiota in aged mice treated with the senolytic agent combination, D+Q (OT; n = 10) versus placebo-treated control (OC; n = 10) mice. *p < .05.

Figure 5.

Reduction in intestinal senescence and inflammation following treatment with senolytic combination, Dasatinib plus Quercetin, correlates with specific and distinct microbiome signatures in small versus large intestine in aged mice. (a–c) Hierarchical heat-maps depicting the Spearman’s correlation of cellular senescence and inflammatory markers with bacterial taxa in ileum (a), caecum (b), and colon (c) of aged mice treated with the senolytic agent combination, D+Q. Correlation networks showing selected subsets (Spearman’s correlation rank between 0.7 and 1.0 [positive correlation] and between −1.0 and −0.7 [negative correlation]; p-value less than .05) of significant correlations of cellular senescence and inflammatory markers with bacterial taxa in ileum (d), caecum (e), and colon (f) of aged mice treated with the senolytic agent combination, D+Q.