6 April 2026

Today’s Visualized examines the backstory of a cover photo. But first, catch up on the latest science news, including NASA’s ambitious Mars shot and how to turn off the cell’s emergency mode.

Cancer | Science

Dendritic cells power down inside tumors—re-energizing them could help kick cancer

Dendritic cells, named for their tree-like branches, are usually immune system superstars. By using their long projections to display fragments of protein, they summon other immune cells to attack invaders and destroy diseased cells. But when dendritic cells find themselves inside a tumor, they tend to run out of steam. According to new research, these cells stop working because their mitochondria—the so-called “powerhouses” of the cell— become degraded.

When scientists examined mice with melanoma, they found that some dendritic cells within the animals’ tumors had perfectly healthy mitochondria, while others were debilitated. As the tumors grew, the number of cells with active mitochondria dwindled. Although it’s unclear exactly why these organelles go on the fritz, the team did determine that a protein called OPA1 appears to be essential to their functioning. Dendritic cells that possessed this protein were much better at rallying other immune cells, while those engineered to lack it were far less effective—leading to more tumor growth. When the researchers injected the rodents’ dendritic cells with lots of additional mitochondria, the animals were able to mount a strong antitumor response and fared better when treated with a type of immunotherapy.

As immunologist Irene Molina and pathologist Malay Haldar write in a related Science Perspective, the findings “pinpoint mitochondrial fitness as an important determinant of therapeutic responsiveness and open opportunities for therapies targeted at dendritic cells.”

Read the Science Paper

Read the Perspective

Astronomy | News from Science

NASA’s ambitious Mars shot

SR-1 Freedom will use electric thrusters, originally designed and built for NASA’s Gateway lunar space station, that shoot out a plasma of ionized xenon. JPL/NASA

For 60 years, planetary scientists, engineers, and businesspeople have been lured by the promise of nuclear power for space. While typical spacecraft move by burning massive quantities of chemical propellant, a fission-powered craft could unlock far more energy with far less fuel, opening up exploration of the outer solar system with massively reduced transit times. But previous attempts at nuclear propulsion have all ended in similar fashions: cost and testing overruns, or a hesitancy from the public to have a nuclear reactor flying overhead.

Needless to say, scientists and engineers were shocked when Jared Isaacman, NASA’s new Administrator, announced a nuclear-powered mission to Mars to take off in only 2 years.

For Jason Cassibry, a propulsion rocket scientist, the first emotion was “excitement,” he told ScienceAdviser. “And then I started thinking, wait, 2028? How in the world are they going to get that done and flown in time?”

The hurdles are numerous. While thrustors and fission reactors have been independently successful, no mission has had to combine them. Reactor heat dissipating through the spacecraft could cause thruster components to expand; vibrations in one element could cause another to fail. Acquiring and transporting uranium fuel is mired in red tape. And there’s the matter of geopolitics: does putting a nuclear reactor in space have thinly shielded military implications?

“The nuclear community has been waiting for this for a very long time,” aerospace engineer Gabe Xu told ScienceAdviser. “But I expect that … the complications involved, not only technical, but also bureaucratic, administrative, and regulatory, are going to make things harder than anyone wishes for.”

Read the full story

Neuroscience | Science

Turning on the cell’s factory

Think of your cells like little factories. When something breaks down, an emergency stop gets triggered, and the protein-making machinery shuts down. This emergency mode, called the integrated stress response (ISR), also promotes the synthesis of proteins needed for recovery. But what happens when the ISR fails to turn off?

In the brain, triggering the ISR halts some neurological functions, a response which has been linked to neurodevelopmental and neurological disorders. To investigate further, a team genetically engineered mice to contain a gene that turns on prolonged ISR. They found that the mice could not form long-term memories associated with a shock to the foot . Then they gave the mice a viral injection to the brain. The virus’ proteins naturally evolved to turn off the ISR, since a cell with paused cellular machinery can’t help a virus replicate.

The shot successfully restored the long-term memory formation of the animals—and could be a promising start to neurological treatments. “For many years, we have essentially had silos of diseases, [such as] Alzheimer's disease [and] Down syndrome,” senior author Mauro Costa-Mattioli told Science podcast host Sarah Crespi.

This study shows that “maybe there’s a common denominator, at least for the cognitive decline that one can tackle.”

Listen to the Science Podcast

Read the paper

SPONSORED

2026 Canada Gairdner Awards Honour Breakthrough Science

Meet the 2026 laureates recognized for groundbreaking discoveries advancing human health, from fundamental biology to global health research, with advances that are transforming our understanding of disease and shaping the future of medicine.

Read Now

Visualized

The 2 April cover of Science magazine. Roy Caldwell/TONMO.com

Researching images for a cover of Science involves culling through hundreds of images from a multitude of sources, with the end goal of finding an image that both informs and visually delights a reader.

As a photo editor, I was recently on a quest to find that one photo that would perfectly depict a rather specific act during octopus mating—the use of a specialized arm by male octopuses that acts as both a sensory and reproductive organ to navigate the female’s mantle, locate oviducts, and transfer sperm . I discovered that photographs of coupling cephalopods are themselves a rare species. Those that I could find showed masses of entwined tan tissue, but could very well have illustrated cuddling or fighting marine species.

A member of the research team for the paper suggested I check out Roy Caldwell’s work, and it was then that I found a veritable treasure trove of images. They were not only literal representations of the research inside the magazine, but in themselves were stunningly beautiful photographs full of color, texture and dimensionality that fit perfectly on the 2 April 2026 cover.

Digging deeper, I also discovered Caldwell, the recently deceased professor emeritus of integrative biology at University of California, Berkeley, left behind a legacy of photographs, research, and fond memories that I felt should be collected in an accompanying blog post.

—Charles Borst, Senior Photo Editor, Science

REad the Science Paper and RELATED PERSPECTIVE

Read the blog post

Et Cetera

Slasher sequel

The White House is again asking Congress to make deep cuts to federal research spending, including a 55% cut to the National Science Foundation, a 23% cut to NASA, a 15% cut to the Department of Energy’s Office of Science, and a 12% cut to the National Institutes of Health. “This budget request should be ignored,” said Representative Zoe Lofgren (D–CA). “It will stymie American science and innovation and hand over our competitiveness to our adversaries.”