A New Method To Measure Intracellular Water In Biological Systems

In this interview, News Medical-Life Sciences speaks pinch Teemu Miettinen, compartment biologist astatine nan Massachusetts Institute of Technology, astir investigation into measuring intracellular h2o and its effect connected cellular usability and disease. Drawing connected caller methodology, Miettinen explains really h2o contented influences biochemical reactions, compartment growth, and emerging investigation in cancer, immunology, and beyond. 

Can you please present yourself and your domiciled astatine MIT?

My sanction is Teemu Miettinen. I americium primitively from Finland, wherever I completed my undergraduate and Master's studies, earlier moving to Scotland for my PhD, which was focused connected compartment size regulation.

For nan past decade, I person been moving astatine nan Massachusetts Institute of Technology, wherever I behaviour investigation to understand really cells modulate their size, growth, and composition.

By training, I'm a compartment biologist and a biochemist, but my activity is centered connected basal compartment biology and connected processing caller methods to measurement biophysical properties of cells. 

One of nan cardinal questions driving my investigation is really compartment size really matters. Cells successful nan quality assemblage tin alteration enormously successful size, spanning up to 7 orders of magnitude, and location is size variability moreover wrong immoderate fixed compartment type. Yet, we still do not afloat understand really this variety impacts cellular function, for illustration a cell's capacity to grow. What we do understand overmuch amended is nan molecular side, peculiarly that nan attraction of molecules wrong cells is captious for biologic processes. And these concentrations sometimes alteration pinch compartment size.

This is wherever compartment creation becomes important. My activity intends to understand what a compartment is fundamentally made of, and a cardinal portion of that mobility is simply a very basal yet amazingly understudied question: really overmuch h2o is really wrong a compartment and really this is regulated. 

Microscopic position of insubstantial composed of densely packed cells, highlighting nan analyzable statement and building that underpin cellular usability and biologic processes. Yet, astir of specified insubstantial wide is water, and nan magnitude of h2o is captious for nan insubstantial function. Image credit: Sinhyu Photographer/Shutterstock.com

Why is intracellular h2o contented truthful important for compartment function?

Water contented is basal because it straight determines nan attraction of each molecule wrong a cell. Since biochemical reactions dangle connected nan concentrations of enzymes and substrates, altering h2o attraction alters guidance rates passim nan cell.

As h2o contented decreases, concentrations increase, which tin accelerate reactions up to a point. However, location is besides an opposing effect. As nan compartment becomes much crowded pinch molecules, diffusion slows down, peculiarly for larger molecules and macromolecular complexes.

This creates a balance. Too small h2o leads to crowding and slower diffusion, while excessively overmuch h2o dilutes molecules and reduces guidance efficiency. As a result, each cellular process whitethorn person its ain optimal h2o content, depending connected its sensitivity to attraction and diffusion.1

What challenges person historically constricted nan measurement of cellular h2o content?

Traditional methods for measuring h2o contented are not well-suited to biologic systems. For example, weighing and drying samples requires ample quantities of worldly and destroys nan samples. Other approaches, specified arsenic Raman spectroscopy-based imaging, tin observe h2o but struggle to separate betwixt h2o wrong and extracurricular nan cell, particularly since cells are typically surrounded by aqueous environments.

Additionally, imaging methods tin beryllium constricted erstwhile moving pinch thicker aliases much analyzable biologic samples, making it difficult to get precise measurements successful physiologically applicable systems. This is why we needed an attack that does not trust connected indirect aliases destructive techniques, but alternatively measures basal beingness properties, specified arsenic mass, much directly.

What caller method person you and your squad developed to flooded these limitations?

We developed a method based connected measuring nan buoyant wide of cells successful different solutions. The attack involves weighing a sample aggregate times successful different fluids, including 1 containing dense water, besides known arsenic deuterium oxide.

To do this, we usage an inertial-sensing system.2 In elemental terms, we travel nan sample done a mini vibrating metallic tube. As nan conduit vibrates, it has a earthy resonance frequency, and erstwhile a compartment aliases organoid passes done it, moreover a mini summation successful wide causes a measurable displacement successful that frequency. It’s very akin to really a guitar drawstring produces a little transportation erstwhile it becomes heavier. By precisely search these wave changes, we tin find nan sample's buoyant wide pinch precocious sensitivity.

By repeating nan measurement successful different solutions, we tin back-calculate nan h2o contented of nan sample successful absolute and comparative (volume/volume) terms, arsenic good arsenic different beingness properties, specified arsenic barren mass.

Importantly, this method does not destruct nan sample and allows america to study much analyzable and physiologically applicable biologic systems, specified arsenic tumor spheroids and organoids.

How does your method disagree from erstwhile technologies successful position of accessibility?

Our earlier activity studying intracellular h2o contented has relied connected highly specialized single-cell wide sensors that are highly powerful, but require custom-built components, important expertise to operate, and are not thing astir labs tin realistically implement.

That’s really thing I’ve ever recovered a spot frustrating. I’ve been fortunate to activity successful a spot wherever we tin do these kinds of measurements, but astatine nan aforesaid time, it intends astir different biologists simply can’t.

With this caller approach, we wanted to move distant from that. The halfway thought was to build thing that is overmuch much accessible successful position of hardware. In principle, each nan components we usage are commercially available. You tin root them from modular suppliers, often moreover from manufacturers extracurricular nan highly specialized technological sector.

Of course, it still requires engineering know-how to combine and optimize nan strategy properly, particularly for controlling vibration and ensuring measurement precision. But there’s thing fundamentally civilization aliases prohibitively costly astir nan hardware. The dream is that this attack makes it overmuch much feasible for different labs to adopt water-content measurements and to commencement exploring these questions much broadly.

How does intracellular h2o contented subordinate to crab biology?

Every guidance successful nan compartment apt has its ain optimal h2o content. We already cognize from a scope of studies that if you alteration nan h2o contented of a cell, for example, by adjusting nan outer osmolarity, you tin straight impact really accelerated that compartment grows. You tin propulsion h2o retired of nan compartment aliases let much to travel in, and that unsocial will alteration its maturation rate. A batch of this activity hasn’t needfully been done successful crab models specifically, but nan aforesaid principles use crossed biology, moreover successful very elemental systems for illustration bacteria. 

So 1 reasonably straightforward presumption is that crab cells person adopted a different intracellular h2o contented to support their precocious maturation rates.

We already spot thing akin successful nan immune system. For example, T cells that are not actively increasing thin to person comparatively debased h2o content, astir 60 %. But erstwhile they go activated and commencement proliferating, their h2o contented increases substantially, going up to 80 %.

So location is simply a clear nexus crossed aggregate systems betwixt h2o contented and growth. We would expect crab cells to travel nan aforesaid benignant of relationship. If that is nan case, past it besides suggests thing much practical. If you tin commencement to perturb nan h2o contented of a crab cell, you are apt going to perturb its maturation arsenic well.

Beyond cancer, what different areas could use from this research?

We are presently looking rather a batch astatine nan immune system, because that’s different area wherever we cognize h2o contented regularisation plays a domiciled successful maturation and function. But much broadly, you tin almost prime immoderate biologic system, and h2o contented is apt to beryllium relevant.

What’s breathtaking astir this method is that it useful crossed very different size scales. We’ve shown it successful tumor spheroids, but successful principle, you could spell overmuch further. You could ideate measuring full organisms, thing for illustration a tardigrade, which tin past utmost dehydration, aliases moreover mini animals like C. elegans. We're besides processing miniaturized versions of nan method, truthful it useful for azygous cells. In fact, we person already recovered extremist h2o contented regularisation successful immoderate marine algae, wherever h2o regularisation mightiness power compartment buoyancy and photosynthesis.3

And because nan method is non-invasive, you tin measurement nan aforesaid sample many times complete time. That intends you tin commencement search really h2o contented changes during maturation aliases successful consequence to different conditions aliases perturbations, which hasn’t really been imaginable before.

How important was interdisciplinary collaboration successful this work?

This investigation would not person been imaginable without an interdisciplinary approach. I’m moving arsenic a portion of a laboratory that is, astatine its core, an engineering lab. It’s focused connected cancer, but it approaches it by building caller tools. And I travel successful arsenic a compartment biologist pinch questions that person been very difficult to reply utilizing existing methods.

So you really request some sides. You request group who tin build measurement systems, and you request group who understand nan biology good capable to inquire nan correct questions.

And it’s not conscionable 1 type of engineering either. There’s mechanical engineering, electrical engineering, and past you besides person to deliberation cautiously astir information analysis, because erstwhile you’re processing a wholly caller method, location isn’t really an established pipeline to follow.

I deliberation a bully illustration of this interdisciplinary work is that astir compartment biologists wouldn’t deliberation astir weighing a compartment successful dense water, and engineers moving pinch biologic systems wouldn’t needfully get astatine that thought either. It really comes from combining those different perspectives. And, of course, location are galore group that person contributed to this complete nan years.

How do you spot this method evolving successful nan future?

One of nan astir breathtaking aspects is that nan method does not destruct nan sample. That instantly opens up galore possibilities. 

You tin commencement combining h2o contented measurements pinch different types of analysis. For example, you could execute high-content imaging alongside it, aliases analyse really nan building of a tumor spheroid relates to its h2o content. You tin besides ideate applying this successful much automated settings, for illustration successful supplier development, wherever you’re testing really different compounds power cellular h2o content.

And beyond that, you could harvester it pinch omics approaches, for example, looking astatine proteomic creation astatine nan aforesaid time.

So really, nan cardinal constituent is that erstwhile nan sample remains intact, you’re nary longer constricted to a azygous measurement. You tin commencement layering different types of information connected apical of each other, which opens up galore directions for really this could create going forward.

We are exploring galore early directions for this work, but I dream others tin subordinate america successful this exploration now that we yet person much devices to study h2o content. 

Where tin readers find much information?

• Explore nan afloat investigation article connected quantifying intracellular h2o successful analyzable 3D biologic systems

• Access nan original investigation exploring really barren wide and molecular creation power phytoplankton sinking behaviour

• Read nan investigation detailing nan trade-off betwixt molecular attraction and diffusion successful crowded cellular environments

About Teemu Miettinen

Teemu P. Miettinen, PhD, is simply a Research Scientist astatine nan Koch Institute for Integrative Cancer Research astatine nan Massachusetts Institute of Technology. He leads investigation seeking to understand really compartment size, growth, and creation are regulated and interconnected. The investigation utilizes various exemplary systems ranging from quality crab and immune cells to single-celled plankton. He besides useful jointly pinch nan laboratory of Prof. Scott Manalis, processing caller biophysical measurements for biomedical applications.

His existent investigation is funded by NIH, he co-holds 2 patents connected measurement technologies, and he has authored respective twelve research papers connected nan regularisation of compartment size, growth, and composition.