Scaling up Cryopreservation from Cell Suspensions to Tissues: Challenges and Successes

This chapter covers the key physical, biological and practical challenges encountered when developing cryopreservation protocols for larger biological structures and examines areas where cryopreservation has been successful in scaling to larger structures. Results from techniques being used in attempts to overcome these challenges are reviewed together with the indicators for future development that arise from them. The scale-up of cryopreservation to tissues with diverse functions and cell types makes the control of freezing and thawing more challenging. Technology may—or may not—be available depending on the size of the material involved. To meet the challenge there must be innovation in technology, techniques and understanding of damage-limiting strategies. Diversity of cell structure, size, shape and expected function means a similarly diverse response to any imposed cryopreservation conditions and interaction with ice crystals. The increasing diffusion distances involved, and diversity of permeability properties, will affect solutes, solvents, heat and cryoprotectant (CPA) transfer and so add to the diversity of response. Constructing a single protocol for cryopreservation of a larger sample (organoids to whole organs) becomes a formidable challenge

Hedgehog signalling promotes Th2-differentiation in naive human CD4 T-cells

Original journal article Abstract: Here we show that differentiation of human naïve CD4 T-cells to Th2 is promoted by Hedgehog signaling and attenuated by SMO-inhibition. As Hedgehog proteins are produced by epithelial tissues this finding is important to understanding atopic disease

Sonic Hedgehog signaling limits atopic dermatitis via Gli2-driven immune regulation.

Hedgehog (Hh) proteins regulate development and tissue homeostasis, but their role in atopic dermatitis (AD) remains unknown. We found that on induction of mouse AD, Sonic Hedgehog (Shh) expression in skin, and Hh pathway action in skin T cells were increased. Shh signaling reduced AD pathology and the levels of Shh expression determined disease severity. Hh-mediated transcription in skin T cells in AD-induced mice increased Treg populations and their suppressive function through increased active transforming growth factor-β (TGF-β) in Tregs signaling to skin T effector populations to reduce disease progression and pathology. RNA sequencing of skin CD4+ T cells from AD-induced mice demonstrated that Hh signaling increased expression of immunoregulatory genes and reduced expression of inflammatory and chemokine genes. Addition of recombinant Shh to cultures of naive human CD4+ T cells in iTreg culture conditions increased FOXP3 expression. Our findings establish an important role for Shh upregulation in preventing AD, by increased Gli-driven Treg cell-mediated immune suppression, paving the way for a potential new therapeutic strategy.MRCWellcome TrustGreat Ormond Street Hospital Children’s Charity (GOSHCC)PfizerNational Institute for Health Research Biomedical Research Centre at GOS