Researchers have generated photosynthetic mammalian cells by transplanting essential components of plant-derived chloroplasts into chondrocytes. When transplanted into degenerating chondrocytes in mice with osteoarthritis, the light-responsive system drives anabolism, preventing disease progression.

Not only does this strategy demonstrate clinical utility, it can treat a wide range of degenerative diseases by using membrane coatings made from different types of mature mammalian cells. It also has implications for generating biofuels and biomaterials. “We think that this work demonstrates that even relatively limited artificial modification of natural biomaterials can achieve specific functions for various applications,” wrote first author Pengfei Chen and senior author Xianfeng Lin in a corresponding research briefing.

The article “A plant-derived natural photosynthetic system for improving cell anabolism” was published in Nature

Essential anabolism

To drive anabolism for cells to generate complex molecules, there needs to be enough energy (ATP) and reducing agents (NADPH). Plants make ATP and NADPH during photosynthesis in thylakoids, a type of sac found inside the chloroplasts of plant cells.

Dysfunctional anabolism is a sign of many diseases. Some treatments for diseases aim to get anabolism going again and fill up the body’s supply of these molecules. But it has been hard for a long time to find a way to fix anabolism that isn’t working right and raise the levels of ATP and NADPH when they aren’t high enough. Simply put, getting energy to cells is difficult in clinical therapeutics and cell biology. Diseased cells need to get these substances in the right amount and in a way that can be controlled.

Photosynthetic mammalian cells

To increase the supply of ATP and NADPH in animal cells, the Zhejiang University School of Medicine researchers created nanoscale structures from chloroplasts known as nanothylakoid units (NTUs). To overcome immune surveillance, they showed that it is possible and useful to transplant NTUs coated in a membrane of the target cell population. The researchers showed that transplantation of NTUs to dysfunctional chondrocytes recovered anabolism. Moreover, transplantation of NTUs into chondrocytes in mice with osteoarthritis prevented disease progression.

The strategy is also not just limited to chondrocytes and has broad clinical application. In principle, it is generalizable because of the interchangeable coating strategy and, therefore, could be used to treat a wide range of degenerative diseases. “We hope to conduct early-stage clinical trials to test the effects of NTUs in degenerative diseases,” wrote the authors.

Not only can this photosynthetic system be used in medicine, but it could also be used to change the metabolism of cells that make biofuels and other useful chemicals. Boosting the metabolism of cells with nanotechnology based on the photosynthetic system could increase biofuel production while lowering costs. This could reduce the need for fossil fuels and, in turn, the amount of carbon dioxide and other gases that contribute to climate change released into the air. This technology could also be used to build platforms for chemical synthesisfor example, to make chemical reagents from resources without producing carbon dioxide.