Expression and function of WNT4 involved in larvae development and limb regeneration in Portunus trituberculatus

The wingless-related integration site(WNT)proteins are a family of secreted glycoproteins that are evolutionarily conserved and are believed to be involved in evolution in vertebrates and invertebrates.WNT signaling pathways may be associated with limb regeneration and development in crustaceans.However,the detail mechanisms remain unclear.Therefore,the distribution of WNT4 in the hepatopancreas,muscle,hemocyte,ganglion,heart,eyestalk,gill tissue,and diff erent larvae development stages of the swimming crab(Portunus trituberculatus)were characterized using immunofl uorescence,real-time PCR,and Western blotting.Signifi cant PtWNT4 expression was detected in heart and eyestalk.In addition,PtWNT4 was expressed in all larval stages of P.trituberculatus with a dynamic expression pattern,especially in the eyestalk and other organs in the carapace area.The injection of WNT4 dsRNA into regenerative limbs signifi cantly decreased PtWNT4 mRNA levels in the eyestalk,heart,and muscle,resulting in 1.9-fold,2.2-fold,and 2.7-fold decreases compared with those detected in the group injected with crab saline(P<0.05),respectively,indicating successful gene silencing.Overall,expression analysis on the WNT4 using RNAi provides an insight to its functional mechanism during limb regeneration in P.trituberculatus.The results not only demonstrated the requirement for WNT4 in limb regeneration of Crustaceans,but also suggested its ability to promote larval development at specifi c stages.

The Quest toward limb regeneration:a regenerative engineering approach

The Holy Grail to address the clinical grand challenge of human limb loss is to develop innovative strategies to regrow the amputated limb.The remarkable advances in the scientific understanding of regeneration,stem cell science,material science and engineering,physics and novel surgical approaches in the past few decades have provided a regenerative tool box to face this grand challenge and address the limitations of human wound healing.Here we discuss the convergence approach put forward by the field of Regenerative Engineering to use the regenerative tool box to design and develop novel translational strategies to limb regeneration.

Potassium channels as potential drug targets for limb wound repair and regeneration

Background:Ion channels are a large family of transmembrane proteins,accessible by soluble membraneimpermeable molecules,and thus are targets for development of therapeutic drugs.Ion channels are the second most common target for existing drugs,after G protein-coupled receptors,and are expected to make a big impact on precision medicine in many different diseases includingwound repair and regeneration.Research has shown that endogenous bioelectric signaling mediated by ion channels is critical in non-mammalian limb regeneration.However,the role of ion channels in regeneration of limbs in mammalian systems is not yet defined.Methods:To explore the role of potassium channels in limb wound repair and regeneration,the hindlimbs of mouse embryos were amputated at E12.5 when the wound is expected to regenerate and E15.5 when the wound is not expected to regenerate,and gene expression of potassium channels was studied.Results:Most of the potassium channels were downregulated,except for the potassium channel kcnj8(Kir6.1)which was upregulated in E12.5 embryos after amputation.Conclusion:This study provides a new mouse limb regeneration model and demonstrates that potassium channels are potential drug targets for limb wound healing and regeneration.

The use of single-cell sequencing to reveal stem/progenitor cells in animal organ regeneration

Advances in single-cell sequencing technologies have made it possible to reveal the cellular basis of complex organ regeneration processes.In this review,we briefly introduce commonly used high-throughput single-cell sequencing platforms and their characteristics.We discuss in depth how single-cell sequencing techniques can be used in the study of regeneration to reveal stem/progenitor cell types and their developmental trajectories.From the perspective of stem cells,we review animal models of regenerative biology and organ models involved in regenerative medicine,with a focus on limb/fin/digit-tip regeneration.Finally,we discuss previous prospective work on improving systematic approaches to explore the origin and evolution of cellular diversity,as well as future research directions.

Gait improvement after treadmill training in ischemic stroke survivors A critical review of functional MRI studies

Stroke survivors often present with abnormal gait, movement training can improve the walking performance post-stroke, and functional MRI can objectively evaluate the brain functions before and after movement training. This paper analyzes the functional MRI changes in patients with ischemic stroke after treadmill training with voluntary and passive ankle dorsiflexion. Functional MRI showed that there are some changes in some regions of patients with ischemic stroke including primary sensorimotor cortex, supplementary motor area and cingulate motor area after treadmill training. These findings suggest that treadmill training likely improves ischemic stroke patients＇ lower limb functions and gait performance and promotes stroke recovery by changing patients＇ brain plasticity; meanwhile, the novel treadmill training methods can better training effects.