The diagnosis of sepsis-associated encephalopathy (SAE), an alteration of conscious from sepsis, is difficult due to the similarity to altered states of conscious that occur from other causes. Transcriptomic analyses between mouse brains at 24 h after cecal ligation and puncture (CLP) (SAE brain as evaluated by SHIRPA score) and at 120 h post-CLP (survivor) were performed to discover the SAE biomarker. Then, candidate microRNAs were validated in mouse and patient samples.As such, increased miR-370-3p in SAE mouse-brains (compared with recovery phase) was demonstrated by transcriptomic miR-profiling and was highly expressed in brain (but not other organs) of 24 h post-CLP mice. Plasma miR-370-3p also increased in CLP but was non-detectable in bilateral-nephrectomy (BiNx, a representative model of acute uremic encephalopathy) despite blood brain barrier permeability defect (determined by plasma s100β and Evan blue dye assay) in both conditions. In parallel, high plasma miR-370-3p was demonstrated in patients with SAE (but not sepsis alone or uremia) suggesting the specificity toward SAE. The association among TNF-α, miR-370-3p and brain apoptosis was demonstrated by high serum TNF-α and increased brain apoptosis in SAE mice, TNF-α (but not other cytokines) activated miR-370-3p expression in PC-12 neuron cell, and increased cell apoptosis in miR-370-3p transfected PC-12 after incubation with TNF-α.In conclusion, miR-370-3p increased in brain and plasma of SAE mice but not uremic encephalopathy. Perhaps, TNF-α enhances cell susceptibility toward brain apoptosis in SAE, in part, through miR-370-3p induction in neuron. Our pilot results in patients with SAE supported the possibility that plasma miR-370-3p is an interesting SAE biomarker candidate. Further studies are warranted.