New function of a key component in the immune system discovered

October 5, 2018, Lund University
Beta cells
Beta cells (green) produce the hormone insulin. Raised levels of micro RNA 200 are harmful. Credit: Masur / Wikimedia Commons

The complement proteins that circulate in our blood are an important part of our immune system. They help identify bacteria, viruses and other harmful organisms, making it easier for our white blood cells to find and neutralise dangerous microbes. Researchers at Lund University in Sweden have now discovered a previously unknown function of the central complement protein, C3, which describes how C3 regulates autophagy.

Autophagy is the basic mechanism that controls cells' ability to break down their own material, i.e. dispose of cellular waste, and generate new energy by reusing their own components. Disruption of the autophagy mechanism is thought to contribute to the development of several diseases. Therefore, this knowledge can play an important role in our understanding of the onset and treatment of type 2 and other diseases.

A few years ago, the research teams led by immunologist Anna Blom and diabetes researcher Erik Renström at Lund University showed that the complement system, which consists of some 40 proteins in the , is also present within our beta cells in the pancreas.

One protein, CD59, was shown to be essential for enabling beta cells to secrete insulin. Another protein, C3, was produced in large amounts in the beta cells, but its exact role was unclear.

In a new study, which has now been published in Cell Metabolism, the researchers discovered that the complement protein C3 can protect the beta cells from stress (e.g. long-term high blood sugar levels) when diabetes is in progress.

When the researchers, using CRISPR/Cas 9, removed the gene that expresses the complement protein C3 from the beta cells, autophagy was disrupted and the cells died more easily from stress. They also found that C3 production in beta cells increases considerably in response to diabetes and inflammation, probably in an attempt to protect .

"C3 is a very old from an evolutionary perspective and we have now shown that it not only has a role in the relatively modern immune system in the blood, but also within cells, where it is needed for one of the most fundamental cellular functions, . In all likelihood, this applies to many cell types and opens the way for new principles in the treatment of diseases such as type 2 diabetes and certain neurodegenerative diseases for which there is a need to protect cells from stress," concludes Anna Blom.

Explore further: Powerful molecules provide new findings about Huntington's disease

More information: Ben C. King et al. Complement Component C3 Is Highly Expressed in Human Pancreatic Islets and Prevents β Cell Death via ATG16L1 Interaction and Autophagy Regulation, Cell Metabolism (2018). DOI: 10.1016/j.cmet.2018.09.009

Related Stories

Powerful molecules provide new findings about Huntington's disease

August 21, 2018
Researchers at Lund University in Sweden have discovered a direct link between the protein aggregation in nerve cells that is typical for neurodegenerative diseases, and the regulation of gene expression in Huntington's disease. ...

New potential target for treatment of diabetes

July 25, 2018
Researchers at Karolinska Institutet have discovered that one of the building blocks in the calcium channels in the pancreatic beta cells play an important role in regulating our blood glucose values. Treatments aimed at ...

Researchers find mechanism that clears excess of protein linked with Type 2 diabetes

July 19, 2014
People with Type 2 diabetes have an excess of a protein called islet amyloid polypeptide, or IAPP, and the accumulation of this protein is linked to the loss of insulin-producing pancreatic beta cells.

Protein packaging may cause the immune attacks of type 1 diabetes

November 21, 2016
Type-1 diabetes occurs when immune cells attack the pancreas. EPFL scientists have now discovered what may trigger this attack, opening new directions for treatments.

Researchers identify new pathway to regenerate insulin-producing cells

September 21, 2015
Researchers at the University of Massachusetts Medical School have discovered a new pathway that triggers regeneration of beta cells in the pancreas, a key development that may aid in the development of diabetes treatments. ...

The relevance of GABA for diabetes highlighted in two new studies

April 5, 2018
Dynamic interactions between the nervous system, hormones and the immune system are normally ongoing, but in diabetes the balance is disturbed. Two studies published in EBioMedicine by an international research team from ...

Recommended for you

A novel insulin accelerant

October 17, 2018
Insulin levels rise after eating a meal, signaling uptake of circulating glucose by skeletal muscle. In individuals with diabetes this process is often impaired—a condition known as insulin resistance.

A bad influence—the interplay between tumor cells and immune cells

October 16, 2018
Research at Huntsman Cancer Institute (HCI) at the University of Utah (U of U) yielded new insights into the environment surrounding different types of lung tumors, and described how these complex cell ecosystems may in turn ...

Function of neutrophils during tumor progression unraveled

October 15, 2018
Researchers at The Wistar Institute have characterized the function of neutrophils, a type of white blood cells, during early stages of tumor progression, showing that they migrate from the bone marrow to distant sites and ...

Immune health maintained by meticulously ordered DNA

October 15, 2018
Walter and Eliza Hall Institute researchers have revealed how immune health is maintained by the exquisite organisation skills of a protein called Pax5.

New immunotherapy targeting blood-clotting protein

October 15, 2018
Normally, the blood protein fibrin does not enter the brain. But in several neurological disorders, the blood-brain barrier—which keeps large molecules in the blood from entering the brain—becomes abnormally permeable, ...

Fat tissue may play a crucial role in the progression of diabetes, challenging long established notions

October 12, 2018
A new study by Australian researchers, out today, is challenging what we know about the causes of diabetes. The new research points to fat tissue as a source of disease, and widens our understanding beyond the traditional ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.