Organoids are self-organized cellular clusters in three-dimensional culture, which can be derived from a single stem cell, progenitor or cell clusters of different lineages resembling in vivo tissue architecture of an organ. In the recent years, organoids technology has contributed to the revolutionary changes in stem cell and cancer fields. In this review, we have briefly overviewed the emerging landscape of prostate organoid technology (POT) in prostate research. In addition, we have also summarized the potential application of POT in the understanding of prostate stem cell and cancer biology and the discovery of novel therapeutic strategies for prostate cancer. Lastly, we have critically discussed key challenges that lie in the current state of POT and provided a future perspective on the second-generation of POT, which should better recapitulate cellular behaviors and drug responses of prostate cancer patients.
Cerebral organoids show great promise as tools to unravel the complex mechanisms by which the mammalian brain develops during embryogenesis. We generated mouse cerebral organoids harbouring constitutive or conditional mutations in Pax6, which encodes a transcription factor with multiple important roles in brain development. By comparing the phenotypes of mutant organoids with the well-described phenotypes of Pax6 mutant mouse embryos, we evaluated the extent to which cerebral organoids reproduce phenotypes previously described in vivo. Organoids lacking Pax6 showed multiple phenotypes associated with its activity in mice, including precocious neural differentiation, altered cell cycle and an increase in abventricular mitoses. Neural progenitors in both Pax6 mutant and wild type control organoids cycled more slowly than their in vivo counterparts, but nonetheless we were able to identify clear changes to cell cycle attributable to the absence of Pax6. Our findings support the value of cerebral organoids as tools to explore mechanisms of brain development, complementing the use of mouse models.
Angiotensin-converting enzyme 2 (ACE2) was identified as the main host cell receptor for the entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its subsequent infection. In some coronavirus disease 2019 (COVID-19) patients, it has been reported that the nervous tissues and the eyes were also affected. However, evidence supporting that the retina is a target tissue for SARS-CoV-2 infection is still lacking. This present study aimed to investigate whether ACE2 expression plays a role in human retinal neurons during SARS-CoV-2 infection. Human induced pluripotent stem cell (hiPSC)-derived retinal organoids and monolayer cultures derived from dissociated retinal organoids were generated. To validate the potential entry of SARS-CoV-2 infection in the retina, we showed that hiPSC-derived retinal organoids and monolayer cultures endogenously express ACE2 and transmembrane serine protease 2 (TMPRSS2) on the mRNA level. Immunofluorescence staining confirmed the protein expression of ACE2 and TMPRSS2 in retinal organoids and monolayer cultures. Furthermore, using the SARS-CoV-2 pseudovirus spike protein with GFP expression system, we found that retinal organoids and monolayer cultures can potentially be infected by the SARS-CoV-2 pseudovirus. Collectively, our findings highlighted the potential of iPSC-derived retinal organoids as the models for ACE2 receptor-based SARS-CoV-2 infection.
The ultrastructure of the pinealocytes of the Malaysian rat (Rattus sabanus), a mammal inhabiting a zone near the equator where the annual variations of daylength are inconspicuous, was examined and compared with that of pinealocytes of other mammals. On the basis of the presence of granular vesicles, only one population of pinealocytes was found. A large number of granular vesicles and vesicle-crowned rodlets is characteristic of the pinealocytes of this equatorial species. Vesicle-crowned rodlets are especially numerous in the endings of the pinealocyte processes and; they most often found in direct topographical connection with the perivascular spaces. The physiological significance of the presence of such large amounts of vesicle-crowned rodlets and of the secretory process characterized by the formation of granular vesicles is discussed.
Specific Escherichia coli isolates lysogenised with prophages that express Shiga toxin (Stx) can be a threat to human health, with cattle being an important natural reservoir. In many countries the most severe pathology is associated with enterohaemorrhagic E. coli (EHEC) serogroups that express Stx subtype 2a. In the United Kingdom, phage type (PT) 21/28 O157 strains have emerged as the predominant cause of life-threatening EHEC infections and this phage type commonly encodes both Stx2a and Stx2c toxin types. PT21/28 is also epidemiologically linked to super-shedding (>103 cfu/g of faeces) which is significant for inter-animal transmission and human infection as demonstrated using modelling studies. We demonstrate that Stx2a is the main toxin produced by stx2a+/stx2c+ PT21/28 strains induced with mitomycin C and this is associated with more rapid induction of gene expression from the Stx2a-encoding prophage compared to that from the Stx2c-encoding prophage. Bacterial supernatants containing either Stx2a and/or Stx2c were demonstrated to restrict growth of bovine gastrointestinal organoids with no restriction when toxin production was not induced or prevented by mutation. Isogenic strains that differed in their capacity to produce Stx2a were selected for experimental oral colonisation of calves to assess the significance of Stx2a for both super-shedding and transmission between animals. Restoration of Stx2a expression in a PT21/28 background significantly increased animal-to-animal transmission and the number of sentinel animals that became super-shedders. We propose that while both Stx2a and Stx2c can restrict regeneration of the epithelium, it is the relatively rapid and higher levels of Stx2a induction, compared to Stx2c, that have contributed to the successful emergence of Stx2a+ E. coli isolates in cattle in the last 40 years. We propose a model in which Stx2a enhances E. coli O157 colonisation of in-contact animals by restricting regeneration and turnover of the colonised gastrointestinal epithelium.
The human brain is made up of billions of neurons and glial cells which are interconnected and organized into specific patternsof neural circuitry, and hence is arguably the most sophisticated organ in human, both structurally and functionally.Studying the underlying mechanisms responsible for neurologicalor neurodegenerativedisorders and the developmental basis of complex brain diseases such as autism, schizophrenia, bipolar disorder, Alzheimer’s and Parkinson’s disease has proven challenging due to practical and ethical limitations on experiments with human material and the limitationsof existing biological/animal models. Recently,cerebral organoids havebeen proposed as apromisingand revolutionary model for understanding complex brain disorders and preclinical drug screening.
Introduction: Currently, organoid technology provides a useful tool for modelling human organ development and pathologies in vitro. Salivary gland (SG) organoids developed from mice SG cells display self-organizing properties closely mimic the native organ. Thus, this study would like to investigate the potential of this organoid system to de-velop a human salivary gland in vitro. Methods: Organoids were developed from biopsy samples of normal human sublingual gland tissue. Cells were isolated and cultured in Matrigel at an Air Liquid Interface (ALI) for up to 14 days in an enriched media supplementing with Wnt-3A, R-spondin1, EGF, and FGF2. Specific differentiation factors like TGFβ, BMP, and LIMK inhibitors were added to enriched media for further differentiation studies. Haematoxylin and eosin-stained sections of the cultures were used to visualise growth. RT-PCR, immunohistochemistry and immunoflu-orescence were used to determine the differential expression of cell-specific markers. Results: Human SG organoids developed when the cells were grown in Matrigel at ALI in a defined culture system. The addition of TGFβ inhibitor and all the inhibitors (TGFβ, BMP and LIMK) to the culture media affected SG organoids development by displaying distinct characteristics that closely resemble native glands and expressed specific cell-type markers; BPIFA2, AQP5, CK5 and E-cadherin. The inhibition of BMP signalling demonstrated SG organoids growth more into ductal-like struc-tures and expressed ductal cell marker, CK7. While LIM kinase inhibition signalling showed significantly higher of amylase activity assay. Conclusion: This study certainly offers valuable insight into determining the optimal culture conditions for developing human SG organoids.