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Research Identifies Beneficial Genetic Changes in Regular Blood Donors

On By ModernMedia
Photo by Charliehelen Robinson on Pexels

Researchers at the Francis Crick Institute have identified genetic changes in blood stem cells from frequent blood donors that support the production of new, non-cancerous cells.

Understanding the differences in the mutations that accumulate in our blood stem cells as we age is important to understand how and why blood cancers develop and hopefully how to intervene before the onset of clinical symptoms.

As we age, stem cells in the bone marrow naturally accumulate mutations and with this, we see the emergence of clones, which are groups of blood cells that have a slightly different genetic makeup. Sometimes, specific clones can lead to blood cancers like leukaemia.

When people donate blood, stem cells in the bone marrow make new blood cells to replace the lost blood and this stress drives the selection of certain clones.

Blood donation impacts makeup of cell populations

In research published in Blood, the team at the Crick, in collaboration with scientists from the DKFZ in Heidelberg and the German Red Cross Blood Donation Centre, analysed blood samples taken from over 200 frequent donors – (three donations a year over 40 years, more than 120 times in total) – and sporadic control donors who had donated blood less than five times in total.

Samples from both groups showed a similar level of clonal diversity, but the makeup of the blood cell populations was different.

For example, both sample groups contained clones with changes to a gene called DNMT3A, which is known to be mutated in people who develop leukaemia. Interestingly, the changes to this gene observed in frequent donors were not in the areas known to be preleukaemic.

A balancing act

To understand this better, the Crick researchers edited DNMT3A in human stem cells in the lab. They induced the genetic changes associated with leukaemia and also the non-preleukaemic changes observed in the frequent donor group.

They grew these cells in two environments: one containing erythropoietin (EPO), a hormone that stimulates red blood cell production which is increased after each blood donation, and another containing inflammatory chemicals to replicate an infection.

The cells with the mutations commonly seen in frequent donors responded and grew in the environment containing EPO and failed to grow in the inflammatory environment. The opposite was seen in the cells with mutations known to be preleukaemic.

This suggests that the DNMT3A mutations observed in the frequent donors are mainly responding to the physiological blood loss associated with blood donation.

Finally, the team transplanted the human stem cells carrying the two types of mutations into mice. Some of these mice had blood removed and then were given EPO injections to mimic the stress associated with blood donation.

The cells with the frequent donor mutations grew normally in control conditions and promoted red blood cell production under stress, without cells becoming cancerous. In sharp contrast, the preleukaemic mutations drove a pronounced increase in white blood cells in both control or stress conditions.

The researchers believe that regular blood donation is one type of activity that selects for mutations that allow cells to respond well to blood loss, but does not select the preleukaemic mutations associated with blood cancer.

Interactions of genes and the environment

Dominique Bonnet, Group Leader of the Haematopoietic Stem Cell Laboratory at the Crick, and senior author, said: “Our work is a fascinating example of how our genes interact with the environment and as we age. Activities that put low levels of stress on blood cell production allow our blood stem cells to renew and we think this favours mutations that further promote stem cell growth rather than disease.

“Our sample size is quite modest, so we can’t say that blood donation definitely decreases the incidence of pre-leukaemic mutations and we will need to look at these results in much larger numbers of people. It might be that people who donate blood are more likely to be healthy if they’re eligible, and this is also reflected in their blood cell clones. But the insight it has given us into different populations of mutations and their effects is fascinating.”

Hector Huerga Encabo, postdoctoral fellow in the Haematopoietic Stem Cell Laboratory at the Crick, and first joint author with Darja Karpova from the DKFZ in Heidelberg, said: “We know more about preleukaemic mutations because we can see them when people are diagnosed with blood cancer.

“We had to look at a very specific group of people to spot subtle genetic differences which might actually be beneficial in the long-term. We’re now aiming to work out how these different types of mutations play a role in developing leukaemia or not, and whether they can be targeted therapeutically.”

Source: The Francis Crick Institute

Categories : Cancer Ethics and Law Neurodegenerative DiseasesTags : 1 Comment

‘Red Flags’ Uncovered in Alzheimer’s and Cancer Research

On By ModernMedia
Image source: National Cancer Institute

The fields of Alzheimer’s disease and cancer research have both been shaken by recent investigations which have revealed image falsification and plagiarism. These findings call into question specific avenues of research which have received considerable funding.

Neuroscientist Matthew Schrag, a junior professor studying Alzheimer’s, had already ruffled some feathers criticising the FDA approval of the Alzheimer’s drug Aduhelm when he was approached by an attorney to investigate Simufilam, another Alzheimer’s drug under development.

According to Science, he used funding given to him by the attorney to investigate the data behind the drug’s development. The research focuses on amyloid beta (Aβ) plaques, long thought to be the culprit behind Alzheimer’s.

Schrag identified apparently altered or duplicated images in dozens of journal articles, and sent them to the National Institutes of Health (NIH), which had funded tens of millions of dollars. 

The investigation drew him towards a bedrock of modern Alzheimer’s research, a 2006 Nature study by Sylvain Lesné of the University of Minnesota in the laboratory of Karen Ashe, which identified an amyloid beta protein.

Schrag avoids describing the suspicious data as fraud, since that would require unfettered access to the original material. “I focus on what we can see in the published images, and describe them as red flags, not final conclusions,” he said. “The data should speak for itself.”

The work focused on ‘toxic oligomers’, subtypes of Aβ that dissolve in some bodily fluids, a potential Alzheimer’s cause that had gained traction in the early 2000s partly due to their discovery in autopsied Alzheimer’s patients.

Using transgenic mice, the UMN team discovered a previously unknown oligomer species, Aβ*56. They isolated Aβ*56 and injected it into young rats, causing a reduction in cognitive ability.

This discovery, the first to show a direct cause, resulted in an explosion in related research, with related studies receiving $287 million in National Institutes of Health funding in 2021, compared to no funding in 2006.

In concert with molecular biologist Elisabeth Bik, no less than 20 of Lesné’s papers were flagged, 10 of which related to Aβ*56. A finding which some Alzheimer’s experts say calls into question 16 years of amyloid beta research. Some had been suspicious and had failed to replicate the findings, but journals are reluctant to publish research which proves a negative or which contradicts a prominent researcher’s findings.

Cancer research has been dogged by its own crisis with fabricated data, according to an investigative report by Nature. For years, a prominent US cancer-research laboratory run by leading cancer geneticist Carlo Croce at the Ohio State University (OSU) had been dogged by allegations of plagiarism and falsified images. To date 11 papers he has co-authored have been retracted, and 21 have needed corrections.

In 2017, The New York Times first reported on allegations of research misconduct against Croce, when OSU opened inquiries into papers from Croce’s lab. These proceeded to formal investigations, Nature learnt, two of which found multiple instances of research misconduct, including data falsification and plagiarism, by scientists Michela Garofalo and Flavia Pichiorri, in papers they’d authored while in Croce’s laboratory.

Garofalo claimed she did not received proper image manipulation training and Pichiorri said she did not understand plagiarism at the time. They have since moved on from OSU.

OSU declined to charge Croce with misconduct as his involvement did not relate to direct plagiarism or image fabrication, but did note that these cases resulted out of his “poor mentorship and lack of oversight.”

Croce was removed from a number of his positions – for which he attempted to sue – but is still employed by OSU, and many of the papers identified by OSU have not been retracted by their journals.