Production of functional sperm from in vitro-cultured premeiotic spermatogonia in a marine fish

In vitro production of functional gametes can revolutionize reproduction by reducing generation intervals and accelerating genetic breeding in aquaculture,especially in fish with relatively long generations.Nevertheless,functional sperm production from in vitro-cultured spermatogonia remains a challenge in most aquaculture fish.In this study,we isolated and characterized premeiotic spermatogonia from marine four-eyed sleepers(Bostrychus sinensis),which are prone to ovotesticular or sterile testicular development,and induced the differentiation of the spermatogonia into flagellated sperm in a three-dimensional(3D)culture system.Artificial insemination indicated that the in vitro-derived sperm were capable of fertilizing mature oocytes to develop into normal larvae.Furthermore,melatonin significantly promoted spermatogonia proliferation and differentiation through the ERK1/2 signaling pathway,and thus increased the efficiency in functional sperm production.The 3D culture system and resulting functional sperm hold great promise for improving the genetic breeding of aquaculture fish.

Three-dimensional cell culture models for investigating human viruses

Three-dimensional(3D) culture models are physiologically relevant, as they provide reproducible results, experimental flexibility and can be adapted for high-throughput experiments. Moreover,these models bridge the gap between traditional two-dimensional(2D) monolayer cultures and animal models. 3D culture systems have significantly advanced basic cell science and tissue engineering, especially in the fields of cell biology and physiology, stem cell research, regenerative medicine, cancer research, drug discovery, and gene and protein expression studies. In addition,3D models can provide unique insight into bacteriology, virology, parasitology and host-pathogen interactions. This review summarizes and analyzes recent progress in human virological research with 3D cell culture models. We discuss viral growth, replication, proliferation, infection, virus-host interactions and antiviral drugs in 3D culture models.

Organ-on-a-chip platforms for accelerating the evaluation of nanomedicine

Nanomedicine involves the use of engineered nanoscale materials in an extensive range of diagnostic and therapeutic applications and can be applied to the treatment of many diseases.Despite the rapid progress and tremendous potential of nanomedicine in the past decades,the clinical translational process is still quite slow,owing to the difficulty in understanding,evaluating,and predicting nanomaterial behaviors within the complex environment of human beings.Microfluidics-based organ-on-a-chip(Organ Chip)techniques offer a promising way to resolve these challenges.Sophisticatedly designed Organ Chip enable in vitro simulation of the in vivo microenvironments,thus providing robust platforms for evaluating nanomedicine.Herein,we review recent developments and achievements in Organ Chip models for nanomedicine evaluations,categorized into seven broad sections based on the target organ systems:respiratory,digestive,lymphatic,excretory,nervous,and vascular,as well as coverage on applications relating to cancer.We conclude by providing our perspectives on the challenges and potential future directions for applications of Organ Chip in nanomedicine.