miRs from the let-7 family directly diminish the expression of MCP-1/CCL2 and RANTES/CCL5 cytokines (Rom et al., 2015), which are complicated in the progression of BBB inflammation that happens during traumatic brain injury (Lumpkins et al., 2008; Albert et al., 2017), various forms of encephalitis (Chowdhury and Khan, 2017) and diabetes (Zhang, 2008; Teler et al., 2017; Lee et al., 2019). The gene discussed is CCL5; the disease is diabetes mellitus.