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Immunotherapy Enhanced by Restoring Mitochondrial Function in Dendritic Cells
In a new study published in Science titled, “Mitochondrial metabolism and signaling direct dendritic cell function in antitumor immunity,” researchers from St. Jude Children’s Research Hospital have uncovered a new metabolic mechanism for how tumors disable immune “gatekeeper” cells that initiate response in the presence of cancer. The results offer a new path to improve immunotherapy.
Dendritic cells alert and activate tumor-killing immune cells as a critical part of anticancer immune response. The authors found that tumors reduce dendritic cell function by minimizing mitochondrial fitness to prevent anticancer immune response. Correspondingly, boosting mitochondrial function in dendritic cells enhances antitumor immune activity and strengthens the efficacy of existing immunotherapies.
Within the nutrient-sparse tumor microenvironment, dendritic cells progressively lose mitochondrial activity, which drives cell dysfunction and weakens immune defenses against cancer. When dendritic cells with high mitochondrial activity were introduced into tumors in preclinical mouse models, results showed that immunogenic activity was restored while improving tumor control.
“We found that tumors reprogram mitochondrial metabolism in dendritic cells, reducing their ability to activate the immune system against cancer,” said Hongbo Chi, PhD, St. Jude Department of Immunology chair and corresponding author of the study. “By enhancing mitochondrial function, we could restore dendritic cell activity and rescue antitumor immunity.”
Immunotherapies for cancer, such as immune checkpoint blockade, have greatly improved care for many malignancies, but have not been successful in all cancers. To determine whether these findings could improve immunotherapy effectiveness in tumor-bearing mice, the authors evaluated the administered dendritic cells with high mitochondrial activity in combination with immune checkpoint blockade.
“We saw the most pronounced therapeutic effect in mice treated with the combination of dendritic cells that had high mitochondrial activity and immune checkpoint blockade,” said co-first author Zhiyuan You, PhD, researcher at St. Jude Department of Immunology. “Those combinations synergistically slowed or stopped tumor growth and extended survival far more than either treatment alone.”
To test long-term effects, the researchers exposed combination therapy treated mice to a new tumor after a few months. New tumor growth stopped for these mice, indicating durable, long-term immune memory.
To better understand the relationship between mitochondrial function and dendritic cells, the researchers examined metabolic pathways affected by the tumor microenvironment. They identified a signaling axis composed of two proteins, OPA1 and NRF1, that regulate communication between mitochondria and the nucleus. Expression was greatly downregulated in dendritic cells during tumor progression and acted as a metabolic switch to shut down dendritic cell immunogenic activity.
“We’re seeing a direct regulation of dendritic cells by the tumor microenvironment,” said co-first author Jiyeon Kim, PhD, researcher at St. Jude Department of Immunology. “We have characterized how that results in mitochondrial reprogramming of dendritic cells to benefit cancer, giving us new opportunities to reverse the process.”
The study’s mechanistic insights enable new directions to rewire dendritic cell function and enhance cancer treatments.
“These findings reinforce the central role of dendritic cells in cancer immunity,” Chi said. “By exploring their mitochondrial function in the tumor microenvironment, we have provided a proof-of-principle of how we may be able to improve the next generation of immunotherapies.”
The post Immunotherapy Enhanced by Restoring Mitochondrial Function in Dendritic Cells appeared first on GEN – Genetic Engineering and Biotechnology News.
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STAT+: At hospital finance conference, a call to end the friction that’s keeping costs high
NATIONAL HARBOR, Md. — At this week’s annual meeting of hospital finance leaders, the exhibit hall was packed with dozens of billing and collections companies. Armed with candy, tote bags, and pens, they smiled at passersby, eager to explain why their tactics would extract the most money from health insurers.
The sheer number of “revenue cycle” vendors who attended the Healthcare Financial Management Association’s annual conference in Maryland — outnumbering even the hospital attendees, according to a list shared by an organizer — was a visible reminder of the enormous industry built around just paying medical bills.
The U.S. health care industry spends roughly $200 billion annually on financial transactions: claims processing, payment, collections, and prior authorization. And yet the proliferation of billing vendors seemed to clash with the main theme of HFMA’s conference, affordability, spotlighting the need to simplify the billing process so that health care is less costly and more accessible for patients.
NATIONAL HARBOR, Md. — At this week’s annual meeting of hospital finance leaders, the exhibit hall was packed with dozens of billing and collections companies. Armed with candy, tote bags, and pens, they smiled at passersby, eager to explain why their tactics would extract the most money from health insurers.
The sheer number of “revenue cycle” vendors who attended the Healthcare Financial Management Association’s annual conference in Maryland — outnumbering even the hospital attendees, according to a list shared by an organizer — was a visible reminder of the enormous industry built around just paying medical bills.
The U.S. health care industry spends roughly $200 billion annually on financial transactions: claims processing, payment, collections, and prior authorization. And yet the proliferation of billing vendors seemed to clash with the main theme of HFMA’s conference, affordability, spotlighting the need to simplify the billing process so that health care is less costly and more accessible for patients.
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Beyond sunshine: Iberia’s biotech moment has arrived with developing capital networks
Strong science, lower costs and growing capital networks are putting Spain and Portugal on the biotech investment map, even as structural bottlenecks persist, according to two investors.
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Laser‑Driven Phase Contrast Enhances Cryo‑EM Resolution of Small Proteins
You know when you are at the eye doctor getting an updated prescription, and suddenly the world snaps into sharper focus? Physicists at the University of California (UC), Berkeley, have now done something similar for electron microscopy. By introducing phase contrast into a cryo‑electron microscope, they have delivered dramatically sharper images of some of biology’s smallest and most elusive proteins.
The advance comes from a new laser phase plate (LPP), described in the paper “Laser phase plate improves structure determination of small proteins by cryo‑EM,” which was published recently in Science. Led by physicist Holger Mueller, PhD, of UC Berkeley and Lawrence Berkeley National Laboratory, the team demonstrated that a laser‑driven phase plate can overcome one of cryo‑EM’s most persistent limitations: poor contrast for small proteins.

Cryo‑EM has transformed structural biology over the past decade, earning a Nobel Prize in 2017 for enabling high‑resolution structures without crystallization. But despite its impact, the technique still struggles with proteins below ~70 kilodaltons—a size range that includes about 90% of the human proteome. “Because of signal-to-noise limitations, the majority of human and animal proteins are too small to be analyzed by these methods [cryo-EM and cryoelectron tomography]. The increase in signal-to-noise ratio provided by this laser phase plate is expected to overcome these important limitations.”
The new LPP begins to address that problem. The LPP uses an intense, continuous‑wave laser to shift the phase of the electron beam itself. This produces true phase contrast without dimming or destabilizing the beam. Mueller described the laser focus as “75 kilowatts focused to a few microns… That’s more powerful than what you use for welding. It has more power than a military laser. It builds up the brightest continuous laser focus ever.”
Installed in a custom Thermo Fisher Titan Krios, the LPP immediately improved the clarity and resolvability of small proteins, including hemoglobin, which sits at the lower limit of what today’s cryo‑EM instruments can handle. As the authors wrote in the abstract: “Here, we show that the laser phase plate (LPP)… enhances the resolution in single-particle reconstruction of small proteins by improving specimen-motion correction, recovery of information from the early frames, as well as particle visualization, 3D classification, and alignment.”

These improvements were achieved using standard defocus ranges and reconstruction workflows. “For the most challenging cases—small particles, bad specimens—the laser produces a very considerable advantage,” Mueller said.
The impact extends beyond single‑particle analysis. Cryo‑electron tomography (cryo‑ET), which assembles multiple angular views of a molecule or protein into a three-dimensional image, stands to benefit even more. “With cryo-ET, we’re looking at small, very complicated cellular material that’s incredibly crowded inside the cell,” said Bridget Carragher, PhD, founding technical director of imaging at Biohub. “It’s like a forest of trees, and you’re trying to find one leaf on one tree in there. Cryo-ET needs a dramatic step forward in contrast, so we can start to see what’s going on inside the cell. That’s what the laser phase plate promises to give us.”
Biohub is developing a dual‑laser version of the system, designed to reduce component wear and minimize aberrations. Meanwhile, Mueller’s team is pushing toward imaging proteins as small as 17 kilodaltons, a threshold that would open access to vast regions of the human proteome previously invisible to cryo‑EM.
“This technology is a step function change for biology,” said Stephani Otte, PhD, Biohub’s vice president of imaging science. “What was once invisible will become visible—and that changes everything about how we understand disease.”
“The bottom line is, if you have a large protein and a really good sample—a fresh one or one frozen without bubbles, for example—you may not need the phase plate to get a single, high-quality image. But for a small protein and a bad sample, laser-on is best,” Mueller said. “This could fill an enormous gap in our knowledge of protein structures that can’t be crystallized or are too small for today’s cryo-EM. And it will be revolutionary for cryo-ET.”
The post Laser‑Driven Phase Contrast Enhances Cryo‑EM Resolution of Small Proteins appeared first on GEN – Genetic Engineering and Biotechnology News.
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