Complex Tissue and Disease Modeling using hiPSCs. Cell Stem Cell. 2016;18:309-321. [PMID: 26942851 DOI: 10.1016/j.stem.2016.02.011]

Dishing out mini-brains: Current progress and future prospects in brain organoid research

The ability to model human brain development in vitro represents an important step in our study of developmental processes and neurological disorders. Protocols that utilize human embryonic and induced pluripotent stem cells can now generate organoids which faithfully recapitulate, on a cell-biological and gene expression level, the early period of human embryonic and fetal brain development. In combination with novel gene editing tools, such as CRISPR, these methods represent an unprecedented model system in the field of mammalian neural development. In this review, we focus on the similarities of current organoid methods to in vivo brain development, discuss their limitations and potential improvements, and explore the future venues of brain organoid research.

3D culture models of tissues under tension

Cells dynamically assemble and organize into complex tissues during development, and the resulting three-dimensional (3D) arrangement of cells and their surrounding extracellular matrix in turn feeds back to regulate cell and tissue function. Recent advances in engineered cultures of cells to model 3D tissues or organoids have begun to capture this dynamic reciprocity between form and function. Here, we describe the underlying principles that have advanced the field, focusing in particular on recent progress in using mechanical constraints to recapitulate the structure and function of musculoskeletal tissues.

Career Advancement: Meeting the Challenges Confronting the Next Generation of Endocrinologists and Endocrine Researchers

CONTEXT

Challenges and opportunities face the next generation (Next-Gen) of endocrine researchers and clinicians, the lifeblood of the field of endocrinology for the future. A symposium jointly sponsored by The Endocrine Society and the Endocrine Society of Australia was convened to discuss approaches to addressing the present and future Next-Gen needs.

EVIDENCE ACQUISITION

Data collection by literature review, assessment of previously completed questionnaires, commissioning of a new questionnaire, and summarization of symposium discussions were studied.

EVIDENCE SYNTHESIS

Next-Gen endocrine researchers face diminishing grant funding in inflation-adjusted terms. The average age of individuals being awarded their first independent investigator funding has increased to age 45 years. For clinicians, a workforce gap exists between endocrinologists needed and those currently trained. Clinicians in practice are increasingly becoming employees of integrated hospital systems, resulting in greater time spent on nonclinical issues. Workforce data and published reviews identify challenges specifically related to early career women in endocrinology. Strategies to Address Issues: Recommendations encompassed the areas of grant support for research, mentoring, education, templates for career development, specific programs for Next-Gen members by senior colleagues as outlined in the text, networking, team science, and life/work integration. Endocrine societies focusing on Next-Gen members provide a powerful mechanism to support these critical areas.

CONCLUSIONS

A concerted effort to empower, train, and support the next generation of clinical endocrinologists and endocrine researchers is necessary to ensure the viability and vibrancy of our discipline and to optimize our contributions to improving health outcomes. Collaborative engagement of endocrine societies globally will be necessary to support our next generation moving forward.

Inherited heart disease - what can we expect from the second decade of human iPS cell research?

Induced pluripotent stem cells (iPSCs) were first generated 10 years ago. Their ability to differentiate into any somatic cell type of the body including cardiomyocytes has already made them a valuable resource for modelling cardiac disease and drug screening. Initially human iPSCs were used mostly to model known disease phenotypes; more recently, and despite a number of recognised shortcomings, they have proven valuable in providing fundamental insights into the mechanisms of inherited heart disease with unknown genetic cause using surprisingly small cohorts. In this review, we summarise the progress made with human iPSCs as cardiac disease models with special focus on the latest mechanistic insights and related challenges. Furthermore, we suggest emerging solutions that will likely move the field forward.

Proteomics of human mitochondria

Proteomics have passed through a tremendous development in the recent years by the development of ever more sensitive, fast and precise mass spectrometry methods. The dramatically increased research in the biology of mitochondria and their prominent involvement in all kinds of diseases and ageing has benefitted from mitochondrial proteomics. We here review substantial findings and progress of proteomic analyses of human cells and tissues in the recent past. One challenge for investigations of human samples is the ethically and medically founded limited access to human material. The increased sensitivity of mass spectrometry technology aids in lowering this hurdle and new approaches like generation of induced pluripotent cells from somatic cells allow to produce patient-specific cellular disease models with great potential. We describe which human sample types are accessible, review the status of the catalog of human mitochondrial proteins and discuss proteins with dual localization in mitochondria and other cellular compartments. We describe the status and developments of pertinent mass spectrometric strategies, and the use of databases and bioinformatics. Using selected illustrative examples, we draw a picture of the role of proteomic analyses for the many disease contexts from inherited disorders caused by mutation in mitochondrial proteins to complex diseases like cancer, type 2 diabetes and neurodegenerative diseases. Finally, we speculate on the future role of proteomics in research on human mitochondria and pinpoint fields where the evolving technologies will be exploited.

Reverse engineering liver buds through self-driven condensation and organization towards medical application

The self-organizing tissue-based approach coupled with induced pluripotent stem (iPS) cell technology is evolving as a promising field for designing organoids in culture and is expected to achieve valuable practical outcomes in regenerative medicine and drug development. Organoids show properties of functional organs and represent an alternative to cell models in conventional two-dimensional differentiation platforms; moreover, organoids can be used to investigate mechanisms of development and disease, drug discovery and toxicity assessment. Towards a more complex and advanced organoid model, it is essential to incorporate multiple cell lineages including developing vessels. Using a self-condensation method, we recently demonstrated self-organizing "organ buds" of diverse systems together with human mesenchymal and endothelial progenitors, proposing a new reverse engineering method to generate a more complex organoid structure. In this section, we review characters of organ bud technology based on two important principles: self-condensation and self-organization focusing on liver bud as an example, and discuss their practicality in regenerative medicine and potential as research tools for developmental biology and drug discovery.

Evaluating cell reprogramming, differentiation and conversion technologies in neuroscience

The scarcity of live human brain cells for experimental access has for a long time limited our ability to study complex human neurological disorders and elucidate basic neuroscientific mechanisms. A decade ago, the development of methods to reprogramme somatic human cells into induced pluripotent stem cells enabled the in vitro generation of a wide range of neural cells from virtually any human individual. The growth of methods to generate more robust and defined neural cell types through reprogramming and direct conversion into induced neurons has led to the establishment of various human reprogramming-based neural disease models.

Utilization of stem cells to model Parkinson's disease – current state and future challenges

Restricted access to patients and low availability of disease-affected tissue often limit possibilities of research on neurodegenerative diseases. In vitro culture systems to model neurodegenerative diseases have been in use for several years, but derivation, maintenance and differentiation of the appropriate cell types was often a challenge. The development of human induced pluripotent stem cells (hiPSCs) was a milestone in the field and rapid progress is happening since. In this review, we highlight the requirements for standardized hiPSC based in vitro disease modeling, with a specific focus on Parkinson's disease. We describe requirements that are already fulfilled and point out current limitations and challenges. These include the induction of aging, the creation of a cellular 3D environment and the generation of alternative neural progenitor cell types, which still need improvement.