Hypothermia-Modulating Matrix Elasticity of Injured Brain Promoted Neural Lineage Specification of Mesenchymal Stem Cells.

Both chemical and physical microenvironments appear to be important for lineage specification of umbilical cord mesenchymal stem cells (UCMSCs). However, physical factors such as the elastic modulus in traumatic brain injury (TBI) are seldom studied. Intracranial hypertension and cerebral edema after TBI may change the brain's physical microenvironment, which inhibits neural lineage specification of transplanted UCMSCs. The purpose of this study is to investigate the potential regulatory effect of mild hypothermia on the elastic modulus of the injured brain. First, we found that more UCMSCs grown on gels mimicking the elastic modulus of the brain (0.5 kPa) differentiated into neural cells, which were verified with the formation of branched cells and the expression of neural markers. Then, UCMSCs were transplanted into TBI rats, and we observed that mild hypothermia resulted in the differentiation of more neurons and astrocytes from transplanted UCMSCs. To demonstrate that more neural specification of UCMSCs was due to the regulation of the elastic modulus, we monitored intracranial pressure and cerebral edema. The results showed that mild hypothermia significantly reduced intracranial pressure and brain water content, indicating modulation of the elastic modulus by mild hypothermia. An examination with atomic force microscopy (AFM) in a cell injury model in vitro further verified hypothermia-regulated elastic modulus. In this study, we found a novel role of mild hypothermia in modulating the elastic modulus of the injured brain, resulting in the promotion of neural lineage specification of UCMSCs, which suggested that the combination of mild hypothermia had more advantages in cell-based therapy after TBI.

Establishment of an ideal time window model in hypothermic-targeted temperature management after traumatic brain injury in rats.

Although hypothermic-targeted temperature management (HTTM) holds great potential for the treatment of traumatic brain injury (TBI), translation of the efficacy of hypothermia from animal models to TBI patientshas no entire consistency. This study aimed to find an ideal time window model in experimental rats which was more in accordance with clinical practice through the delayed HTTM intervention. Sprague-Dawley rats were subjected to unilateral cortical contusion injury and received therapeutic hypothermia at 15mins, 2 h, 4 h respectively after TBI. The neurological function was evaluated with the modified neurological severity score and Morris water maze test. The brain edema and morphological changes were measured with the water content and H&E staining. Brain sections were immunostained with antibodies against DCX (a neuroblast marker) and GFAP (an astrocyte marker). The apoptosis levels in the ipsilateral hippocampi and cortex were examined with antibodies against the apoptotic proteins Bcl-2, Bax, and cleaved caspase-3 by the immunofluorescence and western blotting. The results indicated that each hypothermia therapy group could improve neurobehavioral and cognitive function, alleviate brain edema and reduce inflammation. Furthermore, we observed that therapeutic hypothermia increased DCX expression, decreased GFAP expression, upregulated Bcl-2 expression and downregulated Bax and cleaved Caspase-3 expression. The above results suggested that HTTM at 2h or even at 4h post-injury revealed beneficial brain protection similarly, despite the best effect at 15min post-injury. These findings may provide relatively ideal time window models, further making the following experimental results more credible and persuasive.

The PTTG1-targeting miRNAs miR-329, miR-300, miR-381, and miR-655 inhibit pituitary tumor cell tumorigenesis and are involved in a p53/PTTG1 regulation feedback loop.

Deregulation of the pituitary tumor transforming gene (PTTG1), a newly discovered oncogene, is a hallmark of various malignancies, including pituitary tumors. However, the mechanisms regulating PTTG1 expression are still needed to be explored. MicroRNAs (miRNAs) are a novel class of small RNA molecules that act as posttranscriptional regulators of gene expression and can play a significant role in tumor development. Here, we identified a series of miRNAs, namely, miR-329, miR-300, miR-381 and miR-655, which could target PTTG1 messenger RNA and inhibit its expression. Interestingly, all four miRNAs significantly that are downregulated in pituitary tumors were mapped to the 14q32.31 locus, which acts as a tumor suppressor in several cancers. Functional studies show that the PTTG1-targeting miRNAs inhibit proliferation, migration and invasion but induce apoptosis in GH3 and MMQ cells. Furthermore, overexpression of a PTTG1 expression vector lacking the 3'UTR partially reverses the tumor suppressive effects of these miRNAs. Next, we identified the promoter region of PTTG1-targeting miRNAs with binding sites for p53. In our hands, p53 transcriptionally activated the expression of these miRNAs in pituitary tumor cells. Finally, we found that PTTG1 could inhibit p53 transcriptional activity to the four miRNAs. These data indicate the existence of a feedback loop between PTTG1 targeting miRNAs, PTTG1 and p53 that promotes pituitary tumorigenesis. Together, these findings suggest that these PTTG1-targeting miRNAs are important players in the regulation of pituitary tumorigenesis and that these miRNAs may serve as valuable therapeutic targets for cancer treatment.

MicroRNA-873 (miRNA-873) inhibits glioblastoma tumorigenesis and metastasis by suppressing the expression of IGF2BP1.

Glioblastoma multiforme (GBM) is known as a highly malignant brain tumor with a poor prognosis, despite intensive research and clinical efforts. In this study, we observed that microRNA-873 (miR-873) was expressed at low levels in GBM and that the overexpression of miR-873 dramatically reduced the cell proliferation, migration, and invasion of GBM cells. Our further investigations of the inhibition mechanism indicated that miR-873 negatively affected the carcinogenesis and metastasis of GBM by down-regulating the expression of IGF2BP1, which stabilizes the mRNA transcripts of its target genes. These results demonstrate that miR-873 may constitute a potential target for GBM therapy.