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Renkema, K.

Publications and source records attributed to Renkema, K..

2 recordsLinked to original sources

An enzyme-free, cold-process acoustic method for gentle and effective tissue dissociation

As biological advances continue to improve the resolution of genomic and proteomic studies, the quality of single cell suspensions is becoming increasingly important. While conventional approaches use enzymes which may require heat Abbreviations: Bulk Lateral Ultrasound (BLU) activation to break down extracellular tissue matrices and gain access to single cells, recent studies have suggested that these harsh biochemical and heat-based treatments may result in genomic and proteomic modulation. To minimize these dissociation artifacts, we have developed an instrument for dissociating cells from various tissue matrices using Bulk Lateral Ultrasound (BLU) energy. This enzyme-free, gentle mechanical dissociation maintains sample temperatures below 8{degrees}C for the duration of processing, resulting in high-fidelity single cell suspensions with comparable viability and live cell counts to those obtained with conventional enzymatic dissociations. Here, in murine-derived brain, heart, lung, and B16 melanoma tumor tissue dissociated by either BLU or by a commercially available dissociation kit which uses enzymes and heat, we compare cell viability and expression of population-specific immunological markers. The dramatic differences observed in cell surface expression suggest that cells dissociated using enzymes and heat may be experiencing stress-induced changes post-harvest that could impact conclusions and impede research progress. Alternatively, using gentle mechanical dissociation with BLU, we demonstrate the preservation of these markers and enable a minimally invasive alternative to obtaining high integrity single cell suspensions. HighlightsO_LINovel, acoustic energy-based, enzyme-free dissociation improves single cell suspensions C_LIO_LIEnzymatic dissociation diminishes cell counts, viability, and surface marker expression C_LIO_LIImmunophenotyping reveals marker preservation by acoustic-based dissociaton C_LI

cell biology↗

Non-deletional CD8+ T cell self-tolerance permits responsiveness but limits tissue damage

Self-specific CD8+ T cells often escape clonal deletion, but the properties and capabilities of such cells in a physiological setting are unclear. We characterized polyclonal CD8+ T cells specific for the melanocyte antigen tyrosinase-related protein 2 (Trp2) in mice that express or lack this enzyme due to deficiency in Dct, which encodes Trp2. The size, phenotype, and gene expression profile of the pre-immune Trp2/Kb-specific pool were similar in wild-type (WT) and Dct-deficient (Dct-/-) mice. Despite comparable initial responses to Trp2 immunization, WT Trp2/Kb-specific cells showed blunted expansion, and scRNAseq revealed WT cells less readily differentiated into a CD25+ proliferative population. Functional self-tolerance clearly emerged when assessing immunopathology: adoptively transferred WT Trp2/Kb-specific cells mediated vitiligo much less efficiently. Hence, CD8+ T cell self-specificity is poorly predicted by precursor frequency, phenotype or even initial responsiveness, while deficient activation-induced CD25 expression and other gene expression characteristics may help to identify functionally tolerant cells.

immunology↗