First of all, thrombin was applied on the PC12 cell line to imitate an in vitro ICH condition, but it is Yunaconitine evident that more extensive mechanisms are related to post-hemorrhagic neuronal damage in the real clinical situation.2 It is impossible to simulate perihematomal inflammation or tissue hypoperfusion by an in vitro thrombin injury model. Considering that the PC12 cell line is from pheochromocytoma tissue, the miRNA expression level and protective effect of let7c derived from in vitro thrombin injury may be different from the brain tissue response after ICH. However, the neuroprotective effect of AM let7c in the in vitro thrombin injury model was validated in the vivo ICH model, in which apoptotic cell death was reduced by promoting IGF1R signaling. Only the intranasal delivery of AM let7c was studied in this study, although there is a chance that other administration routes such as intracerebral injection could be more efficient. Future studies regarding dose response, time window, as well as the route of administration will help to strengthen the feasibility of miRNA modulation strategy in ICH. In conclusion, we demonstrated a distinct miRNA expression pattern after ICH and its modulation can have therapeutic potential. The let7c antagomir reduced cell death and inflammation, and enhanced neurological recovery by activating the IGF1R pro-survival pathway. This suggests blocking let7c might be a potential therapeutic target in ICH. A variety of hormones or neurotransmitters, such as adrenaline, dopamine, and prostaglandins, stimulate specific G protein-coupled receptors and activate or suppress adenylate cyclase, leading to an increase or decrease in cAMP. Cyclic AMP directly binds and activates at least three effectors, protein kinase A, exchange protein directly activated by cAMP, and cyclic nucleotidegated channels, and mediates various cellular functions via distinct pathways. Because some cAMP effector proteins are localized only in specific subcellular components, spatial and temporal cAMP dynamics are crucial for regulation of various cellular functions. For investigation of spatial and temporal dynamics of intracellular messenger molecules, such as Ca2+, cAMP and cGMP, two types of genetically-encoded fluorescent indicators have been developed. These indicators are Fo��rster resonance energy transfer -based ratiometric indicators and single fluorescent protein -based intensiometric indicators. FRET-based ratiometric indicators enable monitoring of dynamics of intracellular molecules by a ratio of fluorescence intensity change at two different wavelengths. FP-based intensiometric indicators enable monitoring of dynamics of intracellular molecules by a change in fluorescence intensity of a single wavelength. To monitor cAMP dynamics in cells, several FRET-based cAMP sensors have been CAY10505 generated. The FRET-based cAMP indicators contain a cAMP binding domain in the effector molecules. These are tagged with a pair of FPs, such as cyan FP and yellow FP, for detecting a change in FRET signal induced by binding of cAMP to the domains. Although live-cell imaging using FRET-based cAMP indicators can visualize spatial and temporal dynamics of cAMP, two different emission wavelengths are required for measurement. This limits available wavelengths for multi-color imaging in combination with other signaling molecule indicators. A single FP-based intensiometric indicator is a potential.