Role of mitochondria in regulating micro RNA activity and its relevance to the central nervous system

Mitochondria serve as the powerhouse of cells,respond to cellular demands and stressors,and play an essential role in cell signaling,differentiation,and survival.Aberrant mitochondria function has been linked to diverse and complex human diseases such as neurodegenerative diseases,cancers,myopathies,premature aging,and metabolic syndromes（Nunnari and Suomalainen,2012）.

The future of artificial hibernation medicine:protection of nerves and organs after spinal cord injury

Spinal cord injury is a serious disease of the central nervous system involving irreversible nerve injury and various organ system injuries.At present,no effective clinical treatment exists.As one of the artificial hibernation techniques,mild hypothermia has preliminarily confirmed its clinical effect on spinal cord injury.However,its technical defects and barriers,along with serious clinical side effects,restrict its clinical application for spinal cord injury.Artificial hibernation is a futureoriented disruptive technology for human life support.It involves endogenous hibernation inducers and hibernation-related central neuromodulation that activate particular neurons,reduce the central constant temperature setting point,disrupt the normal constant body temperature,make the body adapt"to the external cold environment,and reduce the physiological resistance to cold stimulation.Thus,studying the artificial hibernation mechanism may help develop new treatment strategies more suitable for clinical use than the cooling method of mild hypothermia technology.This review introduces artificial hibernation technologies,including mild hypothermia technology,hibernation inducers,and hibernation-related central neuromodulation technology.It summarizes the relevant research on hypothermia and hibernation for organ and nerve protection.These studies show that artificial hibernation technologies have therapeutic significance on nerve injury after spinal co rd injury through inflammatory inhibition,immunosuppression,oxidative defense,and possible central protection.It also promotes the repair and protection of res pirato ry and digestive,cardiovascular,locomoto r,urinary,and endocrine systems.This review provides new insights for the clinical treatment of nerve and multiple organ protection after spinal cord injury thanks to artificial hibernation.At present,artificial hibernation technology is not mature,and research fa ces various challenges.Neve rtheless,the effort is wo rthwhile for the future development of medicine.

AGO_18b negatively regulates determinacy of spikelet meristems on the tassel central spike in maize

The maize tassel represents an indeterminate male inflorescence. The number of primordia that a given inflorescence meristem produces is related to its determinacy, i.e., capacity for continued meristem activity.Transcription factors(TFs) controlling determinacy in tassel axillary meristems are well studied in maize, and small RNAs are known to influence tassel development by repressing targets, including tassel-related TFs. As core components of the RNA-inducible silence complex(RISC),Argonaute(AGO) proteins are required for small RNAmediated repression. Here, we characterized the biological function of AGO8b, a tassel-enriched AGO. The abundance of AGO8b transcripts gradually increased during tassel development from inception to gametogenesis and were enriched in the inflorescence meristem and axillary meristems of the tassel. Repressing AGO8b expression resulted in more spikelets, which contributed to a longer central spike of the tassel. Additionally, the transcripts of several HD-ZIP Ⅲ TFs that were canonical targets of micro RNA66(miR66) accumulated in the AGO8b repressed lines. We propose that AGO8b is a negative regulator of the determinacy of inflorescence and axillary meristems, and that it acts by interacting with the miR66-HD-ZIP Ⅲ TF regulatory pathway.