Editing Mitochondrion (section)

=== Donation ===
Some cells donate mitochondria to other cells. Such donations occur in multiple cell types, in organisms such as yeast, molluscs, and rodents. Mitochondrial donation was first observed in 2006. As of 2025, it had not been observed in humans ''[[in vivo]]''. Donations may occur to help damaged cells, trigger tissue repair or the immune system, or to power distressed cells.<ref name=":0">{{Cite journal |last=Conroy |first=Gemma |date=2025-04-08 |title=Cells are swapping their mitochondria. What does this mean for our health? |url=https://www.nature.com/articles/d41586-025-01064-5 |journal=Nature |language=en |volume=640 |issue=8058 |pages=302–304 |doi=10.1038/d41586-025-01064-5 |pmid=40200117 |issn=1476-4687}}</ref>

Researchers cultured human mitochondria-free lung cancer cells with stem cells. The stem cells ejected mitochondria, which were absorbed by the lung cells. The lung cells then recovered their ability to divide and metabolize glucose. Mitochondria were then detected moving among lung, heart, brain, fat, bone, and other cells. Research has not identified how a cell indicates that it needs mitochondrial assistance or how other cells read those indicators.<ref name=":0" />

Various purposes have been observed to explain such donations. These include:<ref name=":0" />

* Restore function and extending lifespans of damaged cells<ref>{{Cite journal |last1=Spees |first1=Jeffrey L. |last2=Olson |first2=Scott D. |last3=Whitney |first3=Mandolin J. |last4=Prockop |first4=Darwin J. |date=2006-01-31 |title=Mitochondrial transfer between cells can rescue aerobic respiration |journal=Proceedings of the National Academy of Sciences |volume=103 |issue=5 |pages=1283–1288 |doi=10.1073/pnas.0510511103 |doi-access=free |pmc=1345715 |pmid=16432190|bibcode=2006PNAS..103.1283S }}</ref><ref>{{Cite journal |last1=Ahmad |first1=Tanveer |last2=Mukherjee |first2=Shravani |last3=Pattnaik |first3=Bijay |last4=Kumar |first4=Manish |last5=Singh |first5=Suchita |last6=Kumar |first6=Manish |last7=Rehman |first7=Rakhshinda |last8=Tiwari |first8=Brijendra K |last9=Jha |first9=Kumar A |last10=Barhanpurkar |first10=Amruta P |last11=Wani |first11=Mohan R |last12=Roy |first12=Soumya S |last13=Mabalirajan |first13=Ulaganathan |last14=Ghosh |first14=Balaram |last15=Agrawal |first15=Anurag |date=January 2014 |title=Miro1 regulates intercellular mitochondrial transport & enhances mesenchymal stem cell rescue efficacy |url=https://doi.org/10.1002/embj.201386030 |journal=The EMBO Journal |volume=33 |issue=9 |pages=994–1010 |doi=10.1002/embj.201386030 |pmid=24431222 |pmc=4193933 |issn=0261-4189}}</ref><ref>{{Cite journal |last1=Hayakawa |first1=Kazuhide |last2=Esposito |first2=Elga |last3=Wang |first3=Xiaohua |last4=Terasaki |first4=Yasukazu |last5=Liu |first5=Yi |last6=Xing |first6=Changhong |last7=Ji |first7=Xunming |last8=Lo |first8=Eng H. |date=July 2016 |title=Transfer of mitochondria from astrocytes to neurons after stroke |journal=Nature |language=en |volume=535 |issue=7613 |pages=551–555 |doi=10.1038/nature18928 |pmid=27466127 |pmc=4968589 |bibcode=2016Natur.535..551H |issn=1476-4687}}</ref>
* Endothelial cell donation to cancer cells can increase chemoresistance<ref>{{Cite journal |last1=Pasquier |first1=Jennifer |last2=Guerrouahen |first2=Bella S. |last3=Al Thawadi |first3=Hamda |last4=Ghiabi |first4=Pegah |last5=Maleki |first5=Mahtab |last6=Abu-Kaoud |first6=Nadine |last7=Jacob |first7=Arthur |last8=Mirshahi |first8=Massoud |last9=Galas |first9=Ludovic |last10=Rafii |first10=Shahin |last11=Le Foll |first11=Frank |last12=Rafii |first12=Arash |date=2013-04-10 |title=Preferential transfer of mitochondria from endothelial to cancer cells through tunneling nanotubes modulates chemoresistance |journal=Journal of Translational Medicine |volume=11 |issue=1 |pages=94 |doi=10.1186/1479-5876-11-94 |doi-access=free |issn=1479-5876 |pmc=3668949 |pmid=23574623}}</ref> or tumorigenic potential.<ref>{{Cite journal |last1=Tan |first1=An S. |last2=Baty |first2=James W. |last3=Dong |first3=Lan-Feng |last4=Bezawork-Geleta |first4=Ayenachew |last5=Endaya |first5=Berwini |last6=Goodwin |first6=Jacob |last7=Bajzikova |first7=Martina |last8=Kovarova |first8=Jaromira |last9=Peterka |first9=Martin |last10=Yan |first10=Bing |last11=Pesdar |first11=Elham Alizadeh |last12=Sobol |first12=Margarita |last13=Filimonenko |first13=Anatolyj |last14=Stuart |first14=Shani |last15=Vondrusova |first15=Magdalena |date=2015-01-06 |title=Mitochondrial genome acquisition restores respiratory function and tumorigenic potential of cancer cells without mitochondrial DNA |url=https://pubmed.ncbi.nlm.nih.gov/25565207 |journal=Cell Metabolism |volume=21 |issue=1 |pages=81–94 |doi=10.1016/j.cmet.2014.12.003 |issn=1932-7420 |pmid=25565207}}</ref>
* Following acute lung injury, stromal cells can donate mitochondria to lung cells, which in turn distributed ATP (fuel) to nearby cells that did not receive mitochondria.<ref>{{Cite journal |last1=Islam |first1=Mohammad Naimul |last2=Das |first2=Shonit R. |last3=Emin |first3=Memet T. |last4=Wei |first4=Michelle |last5=Sun |first5=Li |last6=Westphalen |first6=Kristin |last7=Rowlands |first7=David J. |last8=Quadri |first8=Sadiqa K. |last9=Bhattacharya |first9=Sunita |last10=Bhattacharya |first10=Jahar |date=May 2012 |title=Mitochondrial transfer from bone-marrow–derived stromal cells to pulmonary alveoli protects against acute lung injury |journal=Nature Medicine |language=en |volume=18 |issue=5 |pages=759–765 |doi=10.1038/nm.2736 |pmid=22504485 |pmc=3727429 |issn=1546-170X}}</ref>
* Platelets can donate mitochondria to stem cells which then release molecules that aid in blood vessel formation, which accelerates wound healing. Bone cell donations had a similar effect.
* Maintain the blood-brain barrier
* Maintain macrophage function when their metabolism is disrupted
* Reduce inflammatory response, particularly when donated to T cells. Stem cells cultured from rheumatoid arthritis patients donated fewer mitochondria to T cells than do those from others.

Extracellular mitochondria use multiple modes of transport:<ref name=":0" />

** tunnelling nanotubes that temporarily connect cells to transport various cargo<ref>{{Cite journal |last1=Wang |first1=X. |last2=Gerdes |first2=H.-H. |date=July 2015 |title=Transfer of mitochondria via tunneling nanotubes rescues apoptotic PC12 cells |url=https://www.nature.com/articles/cdd2014211 |journal=Cell Death & Differentiation |language=en |volume=22 |issue=7 |pages=1181–1191 |doi=10.1038/cdd.2014.211 |issn=1476-5403|hdl=1956/10814 |hdl-access=free }}</ref>
** passengers on [[Vesicle (biology and chemistry)|vesicles]] 
** free-floating (typically in blood)
** cell contact/fusion