Erodible thermogelling hydrogels for localized mitochondrial transplantation to the spinal cord

Samir P. Patel, Felicia M. Michael, M. Arif Khan, Brian Duggan, Sam Wyse, Daniel R. Darby, Krishnaroop Chaudhuri, Jonathan T. Pham, Jenna Gollihue, Jason E. DeRouchey, Patrick G. Sullivan, Tom D. Dziubla, Alexander G. Rabchevsky

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

We developed a thermal-gelling, erodible hydrogel system for localized delivery of viable mitochondria in vivo, as well as labeled transplanted mitochondria with specific dyes and/or genetically modified mitochondria tagged with red fluorescence protein (RFP). We also employed cell lines to optimize a hydrogel composed of methylcellulose and hyaluronic acid designed to preserve bioenergetics while facilitating mitochondrial release. We further investigated how transplantation of allogeneic or xenogeneic mitochondria into respective cell lines affects host cellular metabolism, as measured by MTS assay. We found that 70% of mitochondria are released from the hydrogel within 20 min at 37 °C, that the respiratory capacity of hydrogel-released mitochondria over 60 min was greater than those without gel, and that MTR-labeling of mitochondria is not indelible. RFP-tagged transgenic mitochondria isolated from modified SH-SY5Y human neuroblastoma cells showed effective uptake into both naïve SH-SY5Y cells and rat PC-12 cells, notably when released from hydrogel. The hydrogel both protected the mitochondria at physiological conditions in vitro while solidifying and diffusing within 60 min locally in situ. To assess metabolic effects, both cell lines were transplanted with different concentrations of SH-SY5Y or PC-12 cell line-derived mitochondria and all resulted in significant increases in metabolism at 6- and 24-hour after transplantation. Alternatively, transplanted mitochondria at highest concentration from rat brain and spinal cord tissues reduced metabolic activities after 24-hour. Along with hydrogel refinements, we are further investigating whether such metabolic changes are due to alterations in cell proliferation or the number of exogenous mitochondria incorporated into individual host cells.

Original languageEnglish
Pages (from-to)145-155
Number of pages11
JournalMitochondrion
Volume64
DOIs
StatePublished - May 2022

Bibliographical note

Funding Information:
Financial Support: Chair Endowments from the Spinal Cord & Brain Injury Research Center, University of Kentucky (AGR & PGS), DoD W81XWH2010347 (AGR) and NIH R01 NS119337 (AGR & SPP). RFP was gifted by Dr. Joe Springer, SCoBIRC, University of Kentucky-UK). We would like to thank Hope Vaught and Job Tharappel at UK SCoBIRC for expert technical assistance, and Kelley Wiegman (UK Chemical Engineering) for her helpful feedback during the development of the mitochondria release studies.

Publisher Copyright:
© 2022 Elsevier B.V. and Mitochondria Research Society

Keywords

  • Hydrogel
  • MTR
  • MTS
  • Metabolism
  • Mitochondrial transplantation
  • Spinal cord

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology
  • Cell Biology

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