BAF45D cooperates with SMAD signaling and promotes early neural differentiation in P19 and H9 cells

BAF45Dis a member of BAF complex,which may play a crucial role in neural development.PAX6 determines neuroectoderm formation,which is highly level sensitive.BAF45D is required for retinoic acid(RA)induced PAX6 expression.PAX6 expression is also regulated by TGF-beta/SMAD signaling.However,mechanism of such regulation remains elusive.We therefore sought to explore whether BAF45D regulates PAX6 expression through cooperating with TGF-beta/SMAD signaling.Here we identified BAF45D is required for expression of phosphorylated SMAD3 and PAX6 induced by RA.Genome-wide analysis revealed that during RA-induced early neural differentiation,BAF 45D knockdown failed to activate TGF-beta/SMAD signaling and induce expression of STAT3 and SMAD7,two negative regulators of TGF-beta/SMAD signaling.Moreover,in RA treated P19 and H9 cells,BAF45D interacts with BRG1 and phosphorylated SMAD3.

3D printing-based frugal manufacturing of glass pipettes for minimally invasive delivery of therapeutics to the brain

Objective:Intracerebral delivery of agents in liquid form is usually achieved through commercially available and durable metal needles.However,their size and texture may contribute to mechanical brain damage.Glass pipettes with a thin tip may significantly reduce injection-associated brain damage but require access to prohibitively expensive programmable pipette pullers.This study is to remove the economic barrier to the application of minimally invasive delivery of therapeutics to the brain,such as chemical compounds,viral vectors,and cells.Methods:We took advantage of the rapid development of free educational online resources and emerging low-cost 3D printers by designing an affordable pipette puller(APP)to remove the cost obstacle.Results:We showed that our APP could produce glass pipettes with a sharp tip opening down to 20μm or less,which is sufficiently thin for the delivery of therapeutics into the brain.A pipeline from pipette pulling to brain injection using low-cost and open-source equipment was established to facilitate the application of the APP.Conclusion:In the spirit of frugal science,our device may democratize glass pipette-puling and substantially promote the application of minimally invasive and precisely controlled delivery of therapeutics to the brain for finding more effective therapies of brain diseases.

The E3 Ubiquitin Ligase gp78 Protects against ER Stress in Zebrafish Liver

Enhanced endoplasmic reticulum （ER）-associated protein degradation （ERAD） activity by the unfolded protein response （UPR） represents one of the mechanisms for restoring ER homeostasis. In vitro evidence indicates that the mammalian gp78 protein is an E3 ubiquitin ligase that facilitates ERAD by polyubiquitinating and targeting proteins for proteasomal degradation under both physiologic and stress conditions. However, the in vivo function of gp78 in maintaining ER protein homeostasis remains untested. Here we show that like its mammalian counterpart, the zebrafish gp78 is also an E3 ubiquitin ligase as revealed by in vitro ubiquitination assays. Expression analysis uncovered that gp78 is highly expressed in several organs, including liver and brain, of both larval and adult fish. Treatment of larvae or adult fish with tunicamycin induces ER stress and upregulates the expression of several key components of the gp78 ERAD complex in the liver. Moreover, liver-specific overexpression of the dominant-negative form of gp78 （gp78-R2M） renders liver more sensitive to tunicamycin-induced ER stress and enhances the expression of sterol response element binding protein （Srebp）-target genes, which was largely suppressed in fish overexpressing wild-type gp78. Together, these data indicate that gp78 plays a critical role in protecting against ER stress in liver.