Brain organoids are new tool for drug screening of neurological diseases

At the level of in vitro drug screening,the development of a phenotypic analysis system with highcontent screening at the core provides a strong platform to support high-throughput drug screening.There are few systematic reports on brain organoids,as a new three-dimensional in vitro model,in terms of model stability,key phenotypic fingerprint,and drug screening schemes,and particula rly rega rding the development of screening strategies for massive numbers of traditional Chinese medicine monomers.This paper reviews the development of brain organoids and the advantages of brain organoids over induced neurons or cells in simulated diseases.The paper also highlights the prospects from model stability,induction criteria of brain organoids,and the screening schemes of brain organoids based on the characteristics of brain organoids and the application and development of a high-content screening system.

Sonic hedgehog signaling:Alternative splicing and pathogenic role in medulloblastoma

Alternative splicing(AS)produces the different mRNA splicing bodies,which are then translated into multiple protein isoforms and participate in various biological functions.With a deeper understanding of alternative splicing through the study of transcriptomes using high-throughput sequencing-based methods,the correlation between aberrant AS and diseases triggered a great concern,especially abnormal AS and cancer.Medulloblastoma(MB)is an intracranial tumor in children.Sonic hedgehog MB(SHH-MB)accounted for approximately 30%of MB,which is associated with the activation of SHH signaling.Growing evidence shows that aberrant AS is closely related to the tumorigenesis of MB.Here,we briefly introduced the AS and its mechanism.Next,we described canonical/noncanonical hedgehog signaling and its correlation with MB.The main description focused on AS of various regulators in canonical hedgehog signaling in MB.In addition,we also described AS of various regulators in noncanonical hedgehog signaling.Meanwhile,activated hedgehog signaling also induces AS in MB.Then,we pointed out that aberrant AS of hedgehog signaling is associated with different MB subgroups.Finally,we summarized the therapeutic applications of targeted AS in cancer treatment.In summary,further understanding of AS in SHH-MB could develop therapeutic targets for splicing factors which may be a novel therapeutic strategy.

Hippo signaling activates hedgehog signaling by Taz-driven Gli3 processing

The overlapping roles of Hippo and Hedgehog signaling in biological functions and diseases prompt us to inves-tigate their potential interactions.Activation of Hippo signaling enhances the transcriptional output of Hedgehog signaling,and the role of Hippo signaling in regulating Hedgehog signaling relies on the Hippo pathway key effector,Taz.Interestingly,Taz exhibits a gradient expression across the posterior-to-anterior of limb bud mesoderms,similar to Sonic hedgehog(Shh).Importantly,Taz drives PKA to phosphorylate Gli3,resulting in the Gli3 processing into its repressor and attenuation of Hedgehog signaling in the Shh-independent manner.Specifically,Taz deletion in mouse embryonic limb bud mesenchyme not only enhances the Hedgehog signaling but partially restores the phenotypes from Shh deletion in causing severe defects of anteroposterior patterning and digit number and identity.Together,these results uncover Taz-dependent Gli3 processing as a hitherto uncharacterized mechanism controlling Hedgehog signaling,highlighting its cross-regulation by Hippo signaling.

One hour of pilocarpine-induced status epilepticus is sufficient to develop chronic epilepsy in mice, and is associated with mossy fiber sprouting but not neuronal death

Determining the minimal duration of status epilepticus （SE） that leads to the development of subsequent spontaneous seizures （i.e., epilepsy） is important, because it provides a critical timewindow for seizure intervention and epilepsy prevention. In the present study, male ICR （imprinting Control Region） mice were injected with pilocarpine to induce acute sei zures. SE was terminated by diazepam at 10 min, 30 min, 1 h, 2 h and 4 h after seizure onset. Spon taneous seizures occurred in the 1, 2 and 4 h SE groups, and the seizure frequency increased with the prolongation of SE. Similarly, the Morris water maze revealed that the escape latency was significantly increased and the number of target quadrant cross ings was markedly decreased in the 1, 2 and 4 h SE groups. Robust mossy fiber sprouting was observed in these groups, but not in the 10 or 30 min group. In contrast, FluoroJade B staining revealed significant cell death only in the 4 h SE group. The incidence and frequency of spontaneous seizures were corre lated with Timm score （P = 0.004） and escape latency （P = 0.004）. These data suggest that SE longer than one hour results in spontaneous motor seizures and memory deficits, and spontaneous seizures are likely associated with robust mossy fiber sprouting but not neuronal death.

Akt Inhibitor Perifosine Prevents Epileptogenesis in a Rat Model of Temporal Lobe Epilepsy

Accumulating data have revealed that abnormal activity of the mTOR(mammalian target of rapamycin)pathway plays an important role in epileptogenesis triggered by various factors. We previously reported that pretreatment with perifosine, an inhibitor of Akt(also called protein kinase B), abolishes the rapamycin-induced paradoxical increase of S6 phosphorylation in a rat model induced by kainic acid(KA). Since Akt is an upstream target in the mTOR signaling pathway, we set out to determine whether perifosine has a preventive effect on epileptogenesis. Here, we explored the effect of perifosine on the model of temporal epilepsy induced by KA in rats and found that pretreatment with perifosine had no effect on the severity or duration of the KA-induced status epilepticus. However, perifosine almost completely inhibited the activation of p-Akt and p-S6 both acutely and chronically following the KA-induced status epilepticus.Perifosine pretreatment suppressed the KA-induced neuronal death and mossy fiber sprouting. The frequency of spontaneous seizures was markedly decreased in rats pretreated with perifosine. Accordingly, rats pretreated with perifosine showed mild impairment in cognitive functions. Collectively, this study provides novel evidence in a KA seizure model that perifosine may be a potential drug for use in anti-epileptogenic therapy.

Neuroprotective effects of flavonoids extracted from licorice on kainate-induced seizure in mice through their antioxidant properties

A relationship between status epilepticus(SE)and oxidative stress has recently begun to be recognized.To explore whether the flavonoids extracted from licorice(LFs)have any protective effect on kainate(KA)-induced seizure in mice,we treated mice with LFs before and after KA injection.In KA-treated mice,we found that superoxide dismutase(SOD)activity decreased immediately after the onset of seizure at 1 h and then increased at 6 h.It returned to baseline 1 d after seizure and then increased again at 3,7,and 28 d,while malondialdehyde(MDA)content remained at a high level at 1 h,6 h,3 d,7 d,and 28 d,indicating a more oxidized status related to the presence of more reactive oxygen species(ROS).Treatment with LFs before KA injection reversed the seizure-induced change in SOD activity and MDA content at 1 h,6 h,3 d,7 d,and 28 d.Treatment with LFs after seizure decreased KA-induced SOD activity and MDA content at 7 and 28 d.Also,LF pre-and post-KA treatments decreased seizure-induced neuronal cell death.Subsequently,Morris water maze tests revealed that the escape latency was significantly decreased and the number of target quadrant crossings was markedly increased in the LF-treated groups.Thus,our data indicate that LFs have protective effects on seizure-induced neuronal cell death and cognitive impairment through their anti-oxidative effects.

The way of SARS-CoV-2 vaccine development:success and challenges

Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)is the causative agent of coronavirus disease 2019(COVID-19).To halt the pandemic,multiple SARS-CoV-2 vaccines have been developed and several have been allowed for emergency use and rollout worldwide.With novel SARS-CoV-2 variants emerging and circulating widely,whether the original vaccines that were designed based on the wild-type SARS-CoV-2 were effective against these variants has been a contentious discussion.Moreover,some studies revealed the long-term changes of immune responses post SARS-CoV-2 infection or vaccination and the factors that might impact the vaccine-induced immunity.Thus,in this review,we have summarized the influence of mutational hotspots on the vaccine efficacy and characteristics of variants of interest and concern.We have also discussed the reasons that might result in discrepancies in the efficacy of different vaccines estimated in different trials.Furthermore,we provided an overview of the duration of immune responses after natural infection or vaccination and shed light on the factors that may affect the immunity induced by the vaccines,such as special disease conditions,sex,and pre-existing immunity,with the aim of aiding in combating COVID-19 and distributing SARS-CoV-2 vaccines under the prevalence of diverse SARS-CoV-2 variants.

A negative regulator of synaptic development:MDGA and its links to neurodevelopmental disorders

Background Formation of protein complexes across synapses is a critical process in neurodevelopment,having direct implications on brain function and animal behavior.Here,we present the understanding,importance,and potential impact of a newly found regulator of such a key interaction.Data sources A systematic search of the literature was conducted on PubMed(Medline),Embase,and Central-Cochrane Database.Results Membrane-associated mucin domain-containing glycosylphosphatidylinositol anchor proteins(MDGAs)were recently discovered to regulate synaptic development and transmission via suppression of neurexins-neuroligins transsynaptic complex formation.MDGAs also regulate axonal migration and outgrowth.In the context of their physiological role,we begin to consider the potential links to the etiology of certain neurodevelopmental disorders.We present the gene expression and protein structure of MDGAs and discuss recent progress in our understanding of the neurobiological role of MDGAs to explore its potential as a therapeutic target.Conclusion MDGAs play a key role in neuron migration,axon guidance and synapse development,as well as in regulating brain excitation and inhibition balance.

RhoA/Rock activation represents a new mechanism for inactivating Wnt/β-catenin signaling in the aging-associated bone loss

The Wnt/β-catenin signaling pathway appears to be particularly important for bone homeostasis,whereas nuclear accumulation ofβ-catenin requires the activation of Rac1,a member of the Rho small GTPase family.The aim of the present study was to investigate the role of RhoA/Rho kinase(Rock)-mediated Wnt/β-catenin signaling in the regulation of aging-associated bone loss.We find that Lrp5/6-dependent and Lrp5/6-independent RhoA/Rock activation by Wnt3a activates Jak1/2 to directly phosphorylate Gsk3βat Tyr216,resulting in Gsk3βactivation and subsequentβ-catenin destabilization.In line with these molecular events,RhoA loss-or gain-of-function in mouse embryonic limb bud ectoderms interacts genetically with Dkk1 gain-of-function to rescue the severe limb truncation phenotypes or to phenocopy the deletion ofβ-catenin,respectively.Likewise,RhoA loss-of-function in pre-osteoblasts robustly increases bone formation while gain-of-function decreases it.Importantly,high RhoA/Rock activity closely correlates with Jak and Gsk3βactivities but inversely correlates withβ-catenin signaling activity in bone marrow mesenchymal stromal cells from elderly male humans and mice,whereas systemic inhibition of Rock therefore activates theβ-catenin signaling to antagonize aging-associated bone loss.Taken together,these results identify RhoA/Rock-dependent Gsk3βactivation and subsequentβ-catenin destabilization as a hitherto uncharacterized mechanism controlling limb outgrowth and bone homeostasis.

A copper-catalyzed three-component reaction of alkenes,cycloketone oximes and DABCO·(SO_(2))_(2):Direct C(sp^(2))-H cyanoalkylsulfonylation

A copper-catalyzed three-component reaction of alkenes,cycloketone oximes and DABCO·(SO_(2))_(2) is de-veloped,which provides a convenient route for the synthesis of diverse(E)-cyanoalkylsulfonyl alkenes in moderate to good yields with excellent regio-and stereoselectivity.A broad substrate scope with ex-cellent functional group tolerance is observed.A plausible radical pathway is proposed,which involves copper-catalyzed ring-opening C–C bond cleavage of O-acyl oxime and insertion of sulfur dioxide.During the reaction process,cyanoalkyl radical and cyanoalkylsulfonyl radical are the key intermediates.