3 ms·

The fundamental problem of the great majority of so-called “in mice” studies is their use of exactly 1 (one) fully inbred type of mouse — C57BL/6J. Would you t

The fundamental problem of the great majority of so-called “in mice” studies is their use of exactly 1 (one) fully inbred type of mouse — C57BL/6J. Would you trust N=1 clinical trials? In this particular PNAS study you have to be hard-core reader and rummage around in the Methods section to uncover this awkward detail: “Mouse strains used were C57BL/6J (Black 6, Jackson Laboratory; JAX stock #000664), JAX stock #003725 (Gabrd−/− mice on a C57BL/6J background…” No wonder translation fails so often. It is not the mice, it is scientists cutting corners! Some of us working with mice use many different genotypes of mice to ensure somewhat more robust results that have a better chance to generalize across mouse genomes and perhaps even human populations. This is not new news. Here is a classic on this topic in Alzheimer’s research published in Neuron in 2019: https://pubmed.ncbi.nlm.nih.gov/30595332/ https://pubmed.ncbi.nlm.nih.gov/30595332/ One more point: There is a great deal of variation in expression of key genes/proteins mentions in this recent PNAS study, in particular parvalbumin and the GABA receptors. For example parvalbumin protein levels in the hippocampus of different strains of mice at different ages vary over a 20-fold range. Here are the hard data from GeneNetwork.org; https://genenetwork.org/show_trait?trait_id=61839_VFHILDKDKSGFIEEDELGSILK_5&dataset=JAX-BXD-Hip-Pro-log2-0723 https://genenetwork.org/show_trait?trait_id=61839_VFHILDKDKS... And GABA receptors also have high levels of variation in hippocampus and other brain regions. Here is a good paper that compares mouse and human GABA receptor variation. https://pubmed.ncbi.nlm.nih.gov/22506031/ https://pubmed.ncbi.nlm.nih.gov/22506031/

BenFranklin100 2y ago
This is comment is needlessly inflammatory and is not informative of how biomedical research is conducted. First, it’s important to point out to the lay reader that the reason researchers frequently use mice strains in the first place is not “to cut corners”; it as an attempt to manage the incredible variability inherent in biology, especially when one moves to complex systems like living mammals. If the mice in a study have the same genetic background, then it far more likely the effect under study can be observed, and not otherwise buried in the noise as it would if wild mouse strains were used. Using a common mouse strains helps compare studies across different areas of research too. It’s the same reason why so much research is done using HeLa cells. Your post gives the lay reader the impression the researchers were being irresponsible; rather than just using a common strain to demonstrates their point. Second, you apparently weren't being too much of a "hard core' reader (or least explainer to the lay reader) because if you had you would highlight this bit in the Methods section that list the multiple mouse models used: 1. C57BL/6J 2. Gabrd-/- mice on a C57BL/6J background 3 Pvalb-IRES-Cre mice 4. B6.Cg-Gt(ROSA)26Sortm14(CAG-tdTomato)Hze/J 5. ApoE4-TR:5xFAD mice These are not stock C57/Bl6 mice and do carry specific mutations. Finally, as the second half of your post acknowledges and the paper demonstrates, different strains are being used in AD research. There are entire centers dedicated to developing specific mouse strains, many with humanized genes, to attempt to capture specific mutations known to be present in humans, some on C57 background, but many others that are not. Jackson labs has developed several as has several other prominent groups in the field [1]. [1] https://www.jax.org/news-and-insights/2024/july/researchers-are-closing-in-on-a-mouse-model-for-alzheimers-research https://www.jax.org/news-and-insights/2024/july/researchers-...; https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/alz.056498 https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/alz... Lastly, I have no idea if this paper is any good.
- robwwilliams 2y ago
  Yes that paper is great. My comment was directed more at those criticizing mouse models than this particular paper. Techniques are lovely; results are hopeful. But I need to see this generalized before talk about translation in HN or elsewhere, or yet another discussion about lousy mouse models and the necessity of “in mice” in every title. From my point of view my comments were needfully and purposefully inflammatory to break the fever. Hard to believe, but scientists (myself included) can be exceedingly stubborn and resistant to necessary paradigm changes such as incorporating genetic diversity into studies. The principal reason mouse models are critiqued in HN and at NIH is that they are regarded as translationally ineffective. Many of my colleagues often say that mice are poor models of human diseases X, Y, and Z. To be blunt they usually do not really know what they are talking about. What they mean is that B6 is a bad model. But B6 is regarded as THE MOUSE. Is any one human a great model of human traits and diseases? Why do we allow this for experimental work. It truly is N=1. We also have a community-wide fixation on moving all mutations and transgenes on to the glorious or notorious C57BL/6 strain. Without background genetic variation we have fragile models that often do not generalize across strains of mice. “Our current models are mannequins we dress up with sparse data from a few experiments and send down a publication catwalk, praying they don't toddle and trip. What we need are powerful, diverse, and well dressed models that can navigate a landscape, not a catwalk. As a community we have not begun to grapple with this issue, but one certainty is that we will require extraordinarily well structured data sets for humans and for experimental models, to make accurate predictions.” from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2751652/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2751652/ As to your request that I review the Methods section more carefully — done. And I do not see any errors of commission on my part. All of the lines that you list above are C57BL/6J (B6) or congenic mice on a nearly pure B6 background. The first is the reference B6 inbred strain. #2 is a B6 congenic (B6.xxx) #3: The Pvalb mouse is at least a five-generation backcross to B6, and therefore also nearly congenic. This line is likely to have been backcrossed for more generations to B6 at JAX; to the point that it is likely to be >95% B6. #4: The nomenclature of this line clearly states that it is a B6 congenic. The typical minimum number of backcrosses to list as a cogenic is 10, but this is a popular line of mouse and may have been backcrossed for even higher purity. #5: Finally, the APOE4-5XFAD mice are 97% C57BL/6J. “…mice homozygous for APOE4, and hemizygous for the 5XFAD transgenes, on a background strain 97% C57Bl/6J and 3% SJL; mice were then inbred between 5xFAD+ and 5xFAD- resulting in littermates E4+/+:FAD+ and E4+/+:FAD−.”

BenFranklin100 2y ago

This is comment is needlessly inflammatory and is not informative of how biomedical research is conducted. First, it’s important to point out to the lay reader that the reason researchers frequently use mice strains in the first place is not “to cut corners”; it as an attempt to manage the incredible variability inherent in biology, especially when one moves to complex systems like living mammals. If the mice in a study have the same genetic background, then it far more likely the effect under study can be observed, and not otherwise buried in the noise as it would if wild mouse strains were used. Using a common mouse strains helps compare studies across different areas of research too. It’s the same reason why so much research is done using HeLa cells. Your post gives the lay reader the impression the researchers were being irresponsible; rather than just using a common strain to demonstrates their point. Second, you apparently weren't being too much of a "hard core' reader (or least explainer to the lay reader) because if you had you would highlight this bit in the Methods section that list the multiple mouse models used: 1. C57BL/6J 2. Gabrd-/- mice on a C57BL/6J background 3 Pvalb-IRES-Cre mice 4. B6.Cg-Gt(ROSA)26Sortm14(CAG-tdTomato)Hze/J 5. ApoE4-TR:5xFAD mice These are not stock C57/Bl6 mice and do carry specific mutations. Finally, as the second half of your post acknowledges and the paper demonstrates, different strains are being used in AD research. There are entire centers dedicated to developing specific mouse strains, many with humanized genes, to attempt to capture specific mutations known to be present in humans, some on C57 background, but many others that are not. Jackson labs has developed several as has several other prominent groups in the field [1]. [1] https://www.jax.org/news-and-insights/2024/july/researchers-are-closing-in-on-a-mouse-model-for-alzheimers-research https://www.jax.org/news-and-insights/2024/july/researchers-...; https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/alz.056498 https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/alz... Lastly, I have no idea if this paper is any good.

robwwilliams 2y ago
Yes that paper is great. My comment was directed more at those criticizing mouse models than this particular paper. Techniques are lovely; results are hopeful. But I need to see this generalized before talk about translation in HN or elsewhere, or yet another discussion about lousy mouse models and the necessity of “in mice” in every title. From my point of view my comments were needfully and purposefully inflammatory to break the fever. Hard to believe, but scientists (myself included) can be exceedingly stubborn and resistant to necessary paradigm changes such as incorporating genetic diversity into studies. The principal reason mouse models are critiqued in HN and at NIH is that they are regarded as translationally ineffective. Many of my colleagues often say that mice are poor models of human diseases X, Y, and Z. To be blunt they usually do not really know what they are talking about. What they mean is that B6 is a bad model. But B6 is regarded as THE MOUSE. Is any one human a great model of human traits and diseases? Why do we allow this for experimental work. It truly is N=1. We also have a community-wide fixation on moving all mutations and transgenes on to the glorious or notorious C57BL/6 strain. Without background genetic variation we have fragile models that often do not generalize across strains of mice. “Our current models are mannequins we dress up with sparse data from a few experiments and send down a publication catwalk, praying they don't toddle and trip. What we need are powerful, diverse, and well dressed models that can navigate a landscape, not a catwalk. As a community we have not begun to grapple with this issue, but one certainty is that we will require extraordinarily well structured data sets for humans and for experimental models, to make accurate predictions.” from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2751652/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2751652/ As to your request that I review the Methods section more carefully — done. And I do not see any errors of commission on my part. All of the lines that you list above are C57BL/6J (B6) or congenic mice on a nearly pure B6 background. The first is the reference B6 inbred strain. #2 is a B6 congenic (B6.xxx) #3: The Pvalb mouse is at least a five-generation backcross to B6, and therefore also nearly congenic. This line is likely to have been backcrossed for more generations to B6 at JAX; to the point that it is likely to be >95% B6. #4: The nomenclature of this line clearly states that it is a B6 congenic. The typical minimum number of backcrosses to list as a cogenic is 10, but this is a popular line of mouse and may have been backcrossed for even higher purity. #5: Finally, the APOE4-5XFAD mice are 97% C57BL/6J. “…mice homozygous for APOE4, and hemizygous for the 5XFAD transgenes, on a background strain 97% C57Bl/6J and 3% SJL; mice were then inbred between 5xFAD+ and 5xFAD- resulting in littermates E4+/+:FAD+ and E4+/+:FAD−.”