Calcium Signaling Launches Into Zero-G

Private investment in space programs by high-profile billionaires has generated a lot of buzz lately.

In May 2020, Elon Musk’s SpaceX launched NASA astronauts Doug Hurley and Bob Behnken to the International Space Station; a first for a private company. In July 2021, billionaires Jeff Bezos and Richard Branson both blasted off in their own rockets to spend three minutes in orbit, paving the way for commercial space travel.

^{This article is posted on our Science Snippets Blog} 

These activities have also motivated research scientists like Dr. Maik Böhmer, who leads the Zero-G Lab at the Goethe University in Frankfurt, Germany. He wants to understand how microgravity (also called zero gravity or zero-G) affects cartilage development and took Sartorius’s Incucyte^® System along for the ride.

The trouble with microgravity

The videos of astronauts floating and having fun with microgravity are ubiquitous with space travel. But spending months in microgravity, as astronaut often do, can really mess with our bodies. Our bones and muscles, for example, become weak, which is why on televised broadcasts we often see returning astronauts needing help to walk out of their capsule.

Understanding these effects is important for the health and safety of astronauts, and future customers of space tourism!   

Follow the calcium

The Böhmer Lab is investigating the effects of microgravity on cartilage degeneration, which is a problem many astronauts face after a long expedition. One of the questions the lab studies is whether cartilage degeneration in microgravity is linked to changes in calcium signaling.

Calcium is involved in virtually all signaling cascades. As Dr. Böhmer puts it, “People say there are two types of signaling: the ones where calcium is involved and the ones where you don’t know it yet.”

They conducted the study in chondrocytes, the metabolically active cells of bone and cartilage. The cells were engineered to use an irreversible photoconvertible reporter system called CaMPARI (Calcium Modulated Photoactivatable Ratiometric Integrator) for monitoring calcium. CaMPARI changes from green to red florescence if calcium binds at the same time that the photoconversion light is applied. More red means more cytosolic calcium.  

What’s a parabolic flight?

Thanks to parabolic flights scientists can study microgravity without going to space. Parabolic flights create a gravity-free condition on an airplane by flying in a specific way. The whole maneuver, or parabola, involves an upward arch, a leveling off, and then a downward arch. During the pull-up and pull-down stages, passengers experience hyper-G, or double the earth’s gravity. While the plane is level, passengers experience 22 seconds of weightlessness.

Experimental design

A Böhmer lab PhD student took the engineered chondrocytes with the reporter system onboard a parabolic flight to measure cytosolic calcium signaling in microgravity. The fluorescence reading was carried out in the lab using the Incucyte^® Live-Cell Analysis System, after the flight was complete.

This was a deliberate experimental design choice. Altered gravity can affect the performance of analytical instruments, so they analyzed the fluorescence in normal gravity to eliminate any experimental artifacts.

The CaMPARI reporter system is a good fit for this setup; it captures information only when the photoconversion light is applied, and the signal is stable enough for later analysis.

Based on the data, there was no change in fluorescence, meaning cytosolic calcium was not altered when chondrocytes were exposed to microgravity.

Incucyte^® Live-Cell Analysis System made analysis fast

The Böhmer Lab used the Incucyte^® Live-Cell Analysis System to perform non-invasive live cell analysis of chondrocytes, without chemical fixing. With this system, you can use both fluorescence and HD phase imaging modes to monitor cells directly from the incubator.

The biggest advantage, however, was speed.

“It would have taken us with a normal microscope about three weeks to analyze all of the wells that we analyzed from the parabolic flight,” said Dr. Böhmer.

Next, the group plans to repeat the experiments with a chondrocyte organoid system to study microgravity effects in a more biologically relevant context.

Watch the full video to learn more about the assay used in this study and see Böhmer Lab PhD students bouncing around in microgravity.