Quiescence Is the Hardest Part

I recently returned from my honeymoon in Florida, where my husband and I found humor in our inclination for relaxing water rides like the lazy river while steering clear of all the sky-scraping roller coasters that would’ve amused our younger selves.

Not to worry, our trip was filled with its share of thrill and adventure, including swimming with sharks, catching a ride on a dolphin, and an up-close encounter with penguins.

On our 10-hour drive back home to Nashville, we hit heavy traffic around Atlanta. I watched in disbelief as the arrival time on our GPS increased with every mile; it felt as though we were regressing. At one point, it was as though time stood still, because the ETA didn’t budge, no matter how far we traveled.

That feeling of stagnancy is worse than regression. At least in regression you’re going somewhere, even if it’s backwards. Instead, I felt like a hamster on a running wheel with the illusion of travel without actually getting anywhere.

There have been many times where I’ve felt like a car stuck in traffic, or a hamster who has had an epiphany of the futility of its striving. I’ve struggled to reach my desired destinations in time, and I’ve had periods where I’ve felt like no matter how many strides I took, I was no closer to reaching my goals.

Yet, as I consider where I thought I’d be in my life by now, and where I actually am, I couldn’t be more grateful for how things have turned out. I struggle at times to make sense of God’s timing, but I trust that any delay is just a temporary traffic jam, not a permanent road closure. And any detours are opportunities to build strength and resilience.

Consider the tardigrade

Resilience is built into the very fabric of our existence, and all living organisms for that matter. Consider the tardigrade, a microscopic animal that can survive long periods of time without food or water, withstand high levels of radiation that would be considered deadly to humans, and even live in outer space. While not all organisms are as robust as the tardigrade, each has evolved adaptations that enable them to survive the unique challenges of their environments. For example, when lungfish encounter a drought and their habitat starts to dry out, they dig holes in the mud, burry themselves and enter a hibernation-like state until conditions in their environment improve.

Resilience lurks deeper than at just the behavioral level of organisms. I find lessons of resilience at the cellular level, particularly in cells that experience quiescence, a period of pause in their development where they are no longer actively dividing but waiting on the right molecular cues that will signal their eventual release or exit from this arrest. In this reversible state, the cell appears dormant, but is actually quite busy on the inside at a molecular level, preparing itself for its eventual release. These cells actively wait—not the pull-over-to-the-side-of-the-road type of waiting, but the keep-driving-until-traffic-clears kind of waiting. As they wait, they work. As they work, they wait.

Our lives will always bring new goals along with new obstacles that threaten to delay them. But as I ponder the ways of quiescent cells, I find renewed hope and vigor in the waiting.

Out with the old, in with the new

If you’ve ever had a really bad sunburn, especially one that causes your skin to peel, you’ve probably noticed that your skin doesn’t stay that way. Over time, the sunburn heals, the redness goes away, the pain lessens, and any peeling skin is replaced with new healthy skin. This is due in part to cell division, where a single cell physically splits, producing two new daughter cells. A small population of cells within tissues like the skin can divide and replace old, damaged, or dying cells in response to injuries like sunburns, eventually replenishing and repairing it. These special cells are called adult stem cells (ASCs). Their main job is “to maintain and repair the tissue in which they (reside)” throughout the lifetime of the organism.

One thing that makes stem cells unique from other types of cells is that they are unspecialized generalists; they do not have a specific function compared to other cells in the body. For example, cells in the intestine have long finger-like projections called microvilli that enable them to absorb large quantities of nutrients from the digested food that passes their way; red blood cells make a special protein called hemoglobin to help them carry oxygen throughout the body; and nerve cells have branched extensions that allow them to form elaborate communication networks where chemical messages can be rapidly sent and received.

Specialized cells essentially have a specific form (shape and structure) that informs their particular function. While stem cells are not specialists, when they divide, they are capable of both renewing themselves (i.e., producing more stem cells) and giving rise to specialized cells (e.g., stem cells in the intestine produce intestinal cells, stem cells in the liver produce liver cells).

Cells spend more time preparing to divide than they do actually dividing. During this period of preparation, they are actively growing, making proteins they will need when they divide and replicating their DNA so each daughter cell will have an identical copy after division. But most of the cells that make up adult organisms are no longer actively dividing. If they are not actively dividing, what are they doing? What are they preparing for? Are they doing anything at all?

Just because a cell is no longer actively dividing doesn’t mean it will never divide again. Some cells, once they reach a state called senescence, do not divide again (van Deursen, 2014). But most cells “are able to resume proliferation as required (by the tissue or organ in which they reside) to replace cells that have been lost as a result of injury or cell death.”

ASCs are an example of this type of cell. They can enter quiescence, a state where they are not actively dividing, and therefore seemingly dormant, but in actuality they are quite busy at a molecular level preparing themselves for when they will exit this state and eventually divide. If I were a quiescent stem cell, I wonder how I’d feel. Would I busy myself in this manner because I am anxious to leave this state, or would I would find contentment in the waiting, knowing that this was only temporary? Would I wait patiently or restlessly?

Research suggests that quiescence is not a passive, but rather an actively maintained state for stem cells. There are molecular pathways “involved in maintaining a poised state that allows rapid activation.” Studies have also uncovered benefits to a stem cell’s quiescence, including preserving their ability to renew and replenish themselves. Tissues where stem cells lose their ability to enter quiescence tend to lose their “resident stem cell population, which eventually diminishes (their) regenerative capacity.”

Whether or not stem cells have an awareness of the benefits of quiescence, the fact that they have to work while they wait suggests dedication and resilience in the face of what might otherwise seem to be an indefinite, irreversible, and inescapable situation.

Yet still I wait

As cells like the stem cell busy themselves at a molecular level preparing for the time when they will exit quiescence, how can I prepare myself in active anticipation for God’s purpose and plan for my life to unfold? How can I maintain a poised state for rapid growth and primed readiness for his timing? Is it possible to find joy in the preoccupation of quiescence when hope seems deferred?

Just when it seemed like our commute back home from our honeymoon was getting worse, the GPS rerouted us around the traffic, and with much relief we powered through and eventually made it home.

At last, our traffic-induced quiescence had ended. Now I needed to learn to rest on my own, sans traffic.

Ciara Reyes-Ton has a Ph.D. from the University of Michigan in Cellular and Molecular Biology, and teaches at a college in Nashville.