Scary dystopian shit . Picture this: a highly skilled human doctor given an AI assistant that has been (secretly) turned evil and instructed to give actively wrong medical guidance, docs miss it half the time. 75% said everything seemed fine. We better solve alignment, guys.

Brown fat burns more energy in the morning and in the cold, and it barely runs while you sleep. A new preprint finds one mitochondrial protein that responds to the body clock, cold, and dietary fat all at once. Researchers from the University of Copenhagen, UPenn, and collaborators studied SLC25A34, a mitochondrial transporter that no one had assigned a job to. Mitochondria are the compartments in your cells that burn fuel for energy in the form of ATP, and transporters are the gates that move molecules in and out of them. A little primer on some of the concepts of the study: Brown fat is a heat-producing tissue. Its cells run a loop: they build fat in the cytosol, the fluid outside the mitochondria, then burn it inside the mitochondria. Building and burning at the same time looks wasteful. That waste is the point, because it releases energy as heat. In humans, brown fat activity is linked to better metabolic health. What the study found: • Cold exposure raised SLC25A34 about 90-fold in mouse brown fat within 24 hours, making it the most enriched tissue for this gene, ahead of the heart • During sleep, the clock protein REV-ERBα keeps the gene switched off. Waking or cold removes that brake • A fat-sensing protein called PPARα then switches the gene on, and it responds to the fats released when cells break down stored fat • A ketogenic diet (93% fat) made it the second most induced gene in the entire brown fat transcriptome. A standard high-fat diet had a much smaller effect • Silencing the gene in brown fat cells reduced respiration, fat synthesis, and mitochondrial content, and acetyl-CoA levels dropped Acetyl-CoA is the raw material cells use to build fat, and it also helps signal genes to make more mitochondria. The proposed mechanism: when cells make acetyl-CoA outside the mitochondria, a leftover molecule called oxaloacetate gets stranded in the cytosol. SLC25A34 appears to carry it back in, which keeps the building and burning loop moving. Without the transporter, oxaloacetate piled up outside and fell inside the mitochondria. Adding acetate, an alternative source of acetyl-CoA, largely rescued the damage. There is also an early human signal. Across 23 clinical studies, SLC25A34 in subcutaneous fat was linked to lower BMI, waist circumference, triglycerides, and insulin resistance, and to higher HDL. The correlations were small, and no link appeared in belly fat around the organs. This is a preprint, most of the work is in mice and cultured cells, and direct proof that the protein transports oxaloacetate is still pending. Whether the same circuit matters in human brown fat is unknown. What this means for longevity and health optimization: No one has tested whether you can raise SLC25A34 on purpose, so none of this is a protocol. But the findings line up with habits that already have support, and they offer a possible mechanism for why those habits work. • Cold exposure: Cold was the strongest trigger in the study. It fits with research linking regular cold exposure to more active brown fat, though the best dose for people is still unclear • Sleep and circadian rhythm: The clock brake that keeps this gene off at night is released around waking. Consistent sleep and wake times, and morning light, may help your brown fat switch on on schedule • Diet composition: Very high fat intake, as in a ketogenic diet, turned the gene on in mice. That doesn't mean keto boosts brown fat in humans, and a standard high-fat diet had a much smaller effect • Mitochondrial health: Brown fat declines with age and with obesity. Keeping it active may be one way to preserve mitochondrial capacity in a tissue that burns fat and clears glucose The larger point is that timing, temperature, and fuel all converge on the same mitochondrial gate.

Exclusive: When Tessa Montague learned about #CRISPR, the gene-editing system that was supposed to make it easy to modify any organism, she set her sights on the cuttlefish. The Columbia University neuroscientist dreamed of injecting its embryos with genes that would prompt its neurons to fluoresce as they fired. The flashes would let her track how this tentacled creature's brain controls one of its most striking behaviors: camouflaging itself by copying patterns it perceives in its surroundings onto its skin. Unlike most animals, she says, “cuttlefish can actually tell us what they see.” Six years and thousands of embryos later, she has reached a milestone: seven cuttlefish that glow red under fluorescent light. Every cell in their boneless bodies contains a gene encoding a synthetic fluorescent protein—even their eggs and sperm, which means their cuttlebabies glow, too. The work, posted as a preprint, marks the first time anyone has successfully added a new gene to a cephalopod. scim.ag/4ytddWd @NewsfromScience

It's cool. And vaguely horrific. A brain cell has just been filmed reaching into a living neuron and biting out the clumps of protein that cause Parkinson's disease. Not clearing debris from outside. Reaching in and eating.

Two versions of the same gene produce opposite effects on Alzheimer's risk, but until now we didn't know why. A new proteomics study reveals they work through completely different molecular mechanisms. The gene is APOE, the strongest genetic factor for Alzheimer's disease. Everyone inherits two copies, one from each parent. There are three main variants: ε2, ε3, and ε4. Think of these variants as different spellings of the same gene. The difference is tiny at the DNA level, just two amino acid substitutions in the protein, but the functional consequences are massive. ε3 is the most common variant and serves as the baseline. About 60% of people carry two ε3 copies. ε4 is the high-risk variant. If you carry one copy of ε4, your Alzheimer's risk increases 2 to 3-fold compared to ε3/ε3. Two copies raise it up to 12-fold. About 15-20% of the population carries at least one ε4 allele. ε2 is the protective variant. Carriers have reduced Alzheimer's risk and delayed onset compared to ε3/ε3. This variant is rarer, found in about 5-10% of people. Here's the paradox: both ε2 and ε4 alter the same protein, apolipoprotein E, which helps transport cholesterol and other fats in the brain. But ε4 dramatically increases disease risk while ε2 protects against it. Most research has focused on why ε4 is harmful. Almost no one has systematically studied why ε2 is protective. Researchers from multiple institutions analyzed protein levels in blood plasma and cerebrospinal fluid across 3,289 individuals from five different cohorts. They measured thousands of proteins in people carrying ε2, ε3, or ε4 variants, some cognitively healthy and others with Alzheimer's dementia. The key methodological advance: they distinguished proteins altered directly by the APOE variant from proteins altered as downstream consequences of disease. Most studies can't separate these. If a protein is elevated in ε4 carriers with Alzheimer's, is that because ε4 directly changes that protein, or because ε4 causes Alzheimer's and the disease changes the protein? They solved this by measuring proteins in people before amyloid plaques formed. Amyloid pathology is one of the earliest detectable signs of Alzheimer's. By profiling cognitively unimpaired individuals with no amyloid accumulation, the researchers isolated the direct effects of each APOE variant independent of disease. They then used a mediation framework to categorize proteins into two groups: • Upstream mediators: APOE variant → protein change → Alzheimer's disease • Downstream effects: APOE variant → Alzheimer's disease → protein change This distinction matters because upstream mediators are the proteins that might actually drive disease risk. Downstream effects are consequences of pathology that's already underway. APOE2 altered 192 proteins compared to ε3 carriers. These proteins were enriched in cellular maintenance pathways and anti-inflammatory processes. The effects were detectable before any amyloid pathology and remained stable across age and disease progression. APOE4 showed a completely different pattern. A small set of upstream mediators linked to cell cycle regulation and oligodendrocyte precursor cell biology. But a much broader group of proteins reflected vascular dysfunction, immune activation, and proteostatic stress shaped by downstream pathology. Here's the comparison: APOE2: • 192 proteins altered • Dominated by upstream mediators • Enriched in cellular maintenance and anti-inflammatory pathways • Effects independent of disease status • 92% of protein associations remained significant after adjusting for Alzheimer's diagnosis APOE4: • Limited upstream mediators • Broader downstream dysfunction • Vascular, immune, and proteostatic alterations driven by pathology • Effects amplified by disease progression The researchers also found proteins that were oppositely regulated between ε2 and ε4. These allele-specific signatures suggest the two variants don't just differ in magnitude, they operate through distinct molecular architectures. One critical finding: APOE-associated protein changes were detectable in people decades younger than typical Alzheimer's onset and remained stable across the entire aging process. This means the molecular signatures of genetic risk are present long before any clinical symptoms. The stability across age and disease stage suggests these aren't transient responses to pathology. They're persistent molecular states set by the APOE variant you carry, present from early adulthood through late-stage disease. The study also validated findings across multiple tissues (plasma and cerebrospinal fluid) and multiple proteomic platforms (SomaLogic, OLINK, mass spectrometry). This cross-platform replication strengthens confidence that the identified proteins represent real biological signals rather than technical artifacts. The implications: APOE2 and APOE4 shape Alzheimer's risk through fundamentally different mechanisms. APOE2 appears to maintain cellular homeostasis and suppress inflammation through upstream pathways. APOE4 has limited direct protective effects and allows broader downstream dysfunction once pathology begins. This explains why interventions targeting APOE4 might need to address multiple pathways, while APOE2-mimetic strategies might focus on enhancing specific cellular maintenance programs that the protective variant naturally upregulates. The protein signatures identified here also serve as candidate biomarkers for stratifying Alzheimer's risk and monitoring therapeutic response in clinical trials. Because the signatures are detectable in blood plasma, they could be measured non-invasively long before symptoms appear. The limitation is that this remains observational. The study identifies which proteins are altered by each APOE variant, but it doesn't prove which changes are causal drivers of disease versus compensatory responses. Testing causality requires experimental manipulation in model systems or genetic validation studies. Still, the dataset provides the clearest evidence yet that APOE2 and APOE4 don't just have opposite effects on disease risk, they operate through entirely different molecular mechanisms. Understanding those mechanisms is the foundation for developing allele-specific interventions. Right now, we know that genetic Alzheimer's risk is written in protein signatures detectable decades before symptoms, and those signatures differ completely between protective and harmful APOE variants. Whether those signatures can be therapeutically modified is the next question.

For decades, a grisly mystery has buzzed around one fly-killing fungi: No matter when the fungus infects a fly, it always dies at sunset. Now scientists have discovered why. sciencenews.org/article/fly-…