What Happens When Your Cells Enter the "Matrix" – Part 1

Written by Anil Bajnath, MD
Posted November 2, 2021

Dear Longevity Insider,

The extracellular matrix (ECM) is a dynamic structure that provides a structural framework for cellular organization and movement. It is a three-dimensional space, extending between cells that are defined by components produced by the cells themselves as well as cells that they neighbor.

The ECM consists of a dynamic mixture of structural proteins which are typically secreted from the cell into the extracellular environment. The extracellular matrix is made up of many components, including molecules like collagen and elastin, macromolecules like glycoproteins or proteoglycans, proteins like adhesion proteins that allow cells to bind to each other, growth factors that signal new tissue formation, and others.

Collagen is one of the most prominent components of the extracellular matrix. It provides strength and stability to tissues and is primarily responsible for wound healing and tissue repair.

There are many types of glycoproteins, or proteoglycans, which give the matrix its winding appearance, similar to DNA's iconic double helix. These macromolecules allow cells to recognize and bind to the matrix components.

Several types of adhesive proteins promote cell-to-cell contact, which can be found on either side of a plasma membrane where they'll spread out from the cell's surface towards the extracellular matrix. These proteins will crosslink (or bond together) with other adhesive proteins to form a mesh that reinforces the adhesive bond between cells.

Four Major Purposes of the Extracellular Matrix

  1. Containment of Cell Growth: This refers to how the matrix can "wrap" around cells while still allowing them to grow in size while confined by the surrounding ECM.

  2. Cell Signaling and Communication: Cell signaling and communication refer to how cells can send signals through the matrix so that growth and development happen in the right place at the right time.

  3. Binding Cells Together to Form Tissues or Organs: The adhesion proteins that hold cells together can also link them to the extracellular matrix.

  4. Removal of Dead or Damaged Cells From the Body: Cells are constantly dying and being replaced, so the ECM will send signals to attract stem cells that can migrate towards its location within tissue, in order to repair or replace damaged cells.

How Does the Extracellular Matrix Regulate Cell Behavior?

The extracellular matrix is a critical mediator of cell behavior. In fact, cells respond to their environment by changing shape and altering gene expression in order to perform their job properly. 

Cell adhesion: This refers to how cells bind together very tightly with adhesive proteins that can crosslink with other adhesive proteins across the plasma membrane so they strengthen the bond between cells.

In order for cells to join together correctly at the right times and places, they need to be able to sense their environment and respond by sending signals through a network of proteins that bind together in a very specific way. So if a developing embryo is going to form into multiple layers that will eventually become distinct tissues or organs, cells in each layer will need to bind to the ECM and pass signals through it to be able to change shape and function into whatever they're supposed to become.

Three Types of Cell Adhesion:

  1. Integrin: These proteins anchor cells to the extracellular matrix, primarily binding between adhesive proteins on one side of a plasma membrane and "integrin binding sites" on the other side of the plasma membrane.

  2. Cell-Matrix Adhesion: This refers to how cells can bind directly to ECM components, which involves integrins as well as other types of adhesion proteins.

  3. Compartmentalization/Segregation: This refers to how cells can create closed boundaries that will separate different tissues from each other.

In order for cells to be able to create compartments, they need to regulate the way substances enter and exit the local environment. In fact, many types of tissue have a limited list of molecules that can diffuse across their borders in one direction or another – this is called "selective permeability," and it's a feature of many cell types. We'll deep-dive into that on Thursday.

As I mentioned, collagen is one of the most prominent components of the extracellular matrix. Vitamin C is a great source for producing more plump, healthy collagen cells in your body. You could always force yourself to peel anad seven oranges to get the vitamin C (and collagen) you desire.

I take the smarter route. I get seven times the vitamin C I'd get in oranges by eating this instead. I've found it easy, quick, and effective.

To your longevity,

Anil Bajnath MD
CEO/Founder, Institute for Human Optimization
Chief Medical Officer, Longevity Insider HQ