Cells At Work Macrophage Quotes

Conventional economics is the dominant intellectual rationalization of today’s world order. As we’ve overextended the growth phase of our global adaptive cycle, this rationalization has become relentlessly more complex and rigid and progressively less tenable. Breakdown will, all at once, discredit this rationalization and create intellectual space for new ideas to flourish. But this space will be brutally competitive. We can boost the chances that humane alternatives will thrive by working them out in detail and disseminating them as widely as possible beforehand.89 Advance planning means we need to develop a wide range of scenarios and experiment with technologies, organizations, and ideas. We’ll do better at these tasks, and we’ll also do better in the confusing aftermath of breakdown, if we use a decentralized approach to solving our problems, because traditional centralized and top-down approaches aren’t nimble enough, and they stifle creativity. Scientists have found that complex systems that are highly adaptive—like markets and even the immune system of mammals—tend to share certain characteristics. First of all, the individual elements that make up the systems—such as companies in a market economy or T-cells and macrophages in an immune system—are extraordinarily diverse. Second, the power to make decisions and solve problems isn’t centralized in one place or thing; instead, it’s distributed across the system’s elements. The elements are then linked in a loose network that allows them to exchange information about what works and what doesn’t. Often in a market economy, for example, several companies will be working at the same time to solve different parts of a shared problem, and important information about solutions will flow between them. Third and finally, highly adaptive systems are unstable enough to create unexpected innovations but orderly enough to learn from their failures and successes. Systems with these three characteristics stimulate constant experimentation, and they generate a variety of problem-solving strategies.90 We

In the early 2000s this idea of synaptic pruning was well established, but how the process actually occurred was a bit of a mystery. In 2007 Beth Stevens, a postdoctoral scientist working in the late Ben Barres’s lab at Stanford University, found a very unexpected answer. In the immune system, specific immune molecules called complement proteins attach themselves to microbes or damaged cells and act as an ‘EAT ME!’ signal to macrophages. Beth found that mice that lacked complement proteins were unable to prune their synapses.18 A few years later, in 2013, after Beth Stevens had moved to Boston Children’s Hospital to start her own lab, she and her postdoctoral fellow Dorothy Schafer found that once these unused synapses are coated in complement proteins, microglia turn up to engulf and destroy them (like coating any food in chocolate sauce when there’s a young child in the vicinity).19 Stevens’s team later found that the synapses that are in regular use produce a ‘DON’T EAT ME!’ signal (like covering a child’s meal in kale).20 Microglia are not just the brain’s equivalent of macrophages, they are the sculptors of our brains. If microglia are to be renamed – a suggestion made by some, as they are not true glial cells – my suggestion would be ‘microangelos’. Although, somehow, I don’t see that catching on. Microglia’s role in synaptic pruning may also have significant relevance for developmental disorders. Abnormalities in neuronal pruning can be seen in subsets of people with neurodevelopmental conditions such as schizophrenia. While we don’t yet know exactly how these alterations in brain connectivity manifest in disease, there is hope that treatments targeting microglia and complement proteins may one day be of great use.