bims-medica 2026-03-22 papers

Issue of 2026–03–22
six papers selected by
Brett Chrest, Wake Forest University

J Physiol. 2026 Mar 14.

Demonstration of beat-to-beat, on-demand ATP synthesis in ventricular myocytes reveals sex-specific mitochondrial and cytosolic dynamics.

Paula Rhana, Collin Matsumoto, L Fernando Santana.

The energetic demands on ventricular myocytes imposed by the transport of ions and cross-bridge cycling are well known, yet the spatiotemporal dynamics of ATP supply and demand remain poorly understood. Here, using confocal microscopy and genetically encoded fluorescent sensors targeted to mitochondria and cytosol, we visualized beat-to-beat ATP dynamics in ventricular myocytes from male and female mice. These probes showed fluctuations in mitochondrial ATP levels with each contraction, revealing two distinct, spatially localized waveforms - ATP 'gain' and ATP 'dip' - representing transient increases or decreases in matrix ATP levels, respectively. These waveforms were tightly phase-locked to intracellular Ca2+ transients and organized into energetic microdomains. Inhibition of the mitochondrial Ca2+ uniporter or the adenine nucleotide translocase attenuated these ATP transients. Although female myocytes exhibited larger mitochondrial ATP transients than their male counterparts, their mitochondrial volume was lower. Female myocytes also exhibited tighter coupling between the sarcoplasmic reticulum and mitochondria and showed a higher density of mitofusin 2 and ATP synthase catalytic α-subunit per unit volume, suggesting more efficient ATP production. Cytosolic ATP transients mirrored mitochondrial waveforms and domain structure in both male and female myocytes. During faster pacing, diastolic cytosolic ATP rose more rapidly in female myocytes, whereas beat-locked ATP transients increased in both sexes but proportionally more in males than in females. These findings demonstrate that ATP is synthesized on a beat-to-beat basis in a modular, microdomain-specific manner. We propose that male myocytes rely on greater mitochondrial mass for energetic scaling, whereas female cells employ architectural precision to optimize ATP delivery. KEY POINTS: It is known that each heartbeat requires precise ATP delivery to fuel ion transport and cross-bridge cycling, but the timing and spatial organization of ATP production in heart cells has been unclear. Using advanced imaging and genetically encoded sensors, we visualized beat-to-beat ATP fluctuations in the mitochondria and cytosol of individual male and female mouse ventricular myocytes. Mitochondrial ATP levels rose or fell with each beat in spatially confined regions, forming ATP 'gain' or 'dip' microdomains that were synchronized with Ca2+ transients. At higher firing rates, beat-locked, diastolic ATP transients rose more quickly in female myocytes, but were larger in male myocytes, highlighting distinct sex-specific strategies for matching energy supply to contractile demand. Ventricular myocytes 'live paycheck-to-paycheck', producing just enough ATP on demand to fuel each beat. Male and female myocytes adopt distinct strategies to meet this demand: male myocytes scale output through greater mitochondrial mass, while female myocytes achieve energetic precision via enhanced sarcoplasmic reticulum-mitochondrial coupling.

Keywords: excitation–contraction coupling; excitation–metabolic coupling; mitochondria; oxidative phosphorylation

DOI: https://doi.org/10.1113/JP289683

Beilstein J Org Chem. 2026 ;22 455-460

Structural reassignment of compound 968, an allosteric glutaminase inhibitor.

Lindsey A Albertelli, Sainabou Jallow, Chun Li, Scott M Ulrich.

Many cancer cells require extracellular glutamine to meet the energetic, biosynthetic, and redox demands of the proliferative state. Glutaminases catalyze the hydrolysis of glutamine to glutamate, which supports the biosynthesis of amino acids, lipids, and glutathione and can also be oxidatively deaminated to α-ketoglutarate and enter the citric acid cycle. The "glutamine addiction" of cancer cells has made glutaminase an attractive anticancer drug target. Compound 968 is a glutaminase inhibitor that is widely used to probe cancer cells' dependence on glutaminase activity. Here, we show by NMR spectroscopy and X-ray crystallography that the reported benzo[c]phenanthridine structure of compound 968 is incorrect; its true structure is the isomeric benzo[c]acridine. The structural reassignment of compound 968 will aid the medicinal chemistry development of this important compound.

Keywords: cancer metabolism; compound 968; glutaminase

DOI: https://doi.org/10.3762/bjoc.22.33

Front Nutr. 2026 ;13 1717096

Bibliometric analysis of ketogenic diet for pain based on dual databases: global trends and research hotspots from the Web of Science Core Collection and Scopus (2006-2025).

Mo Liao, Xinhui Cheng, Fei Liu, Xingjuan Xiong, Yongsheng Yu.

Objective: The ketogenic diet (KD) has demonstrated beneficial effects on pain, yet no bibliometric study has systematically explored this association. This study aimed to evaluate global research trends and emerging hotspots on "ketogenic diet for pain" from 2006 to 2025, providing quantitative evidence and forward-looking perspectives for future basic and clinical research.
Methods: Publications from 2006 to 2025 were retrieved from the Web of Science Core Collection (WoSCC) and Scopus databases. Bibliometric analyses were conducted using Bibliometrix (R package), VOSviewer, and CiteSpace to assess performance and generate visualizations.
Results: This study included 328 eligible publications from the WoSCC and 786 from the Scopus database. From 2006 to 2021, the annual number of publications on KD-related pain research showed a sustained upward trend, followed by a phase of high-level fluctuation between 2022 and 2025. The United States emerged as the leading contributing country. An international collaboration network was formed, with the University of Basel (Switzerland) and Sapienza University of Rome (Italy) serving as central hubs. Nutrients published the largest number of articles and received widespread citations, whereas Cephalalgia was the most frequently cited journal. Nutrients and Epilepsia functioned as key academic collaboration hubs. Keyword co-occurrence and clustering analyses identified three major thematic domains: (1) the direct analgesic effects of the KD and its role in the management of chronic inflammatory pain; (2) the neuroprotective mechanisms of the KD and its synergistic analgesic effects when combined with pharmacological therapies; and (3) the improvement of comorbid mood disorders and the mitigation of metabolic risks associated with ketogenic dietary interventions. Current research hotspots focus on dietary strategies for migraine management, the application of KD in chronic pain conditions, and ketone body-mediated anti-inflammatory and neuromodulatory mechanisms.
Conclusion: Research on the beneficial role of KD in pain management has attracted growing global attention and is expected to become an important direction in future pain management. This study provides a comprehensive bibliometric overview of the current status and research hotspots, offering valuable guidance for subsequent investigations.

Keywords: bibliometric analysis; dual-database approach; ketogenic diet; pain management; research hotspots

DOI: https://doi.org/10.3389/fnut.2026.1717096

J Acad Nutr Diet. 2026 Mar 16. pii: S2212-2672(26)00046-8. [Epub ahead of print] 156331

Relative Effects of Time-Restricted Eating, Energy-Restricted Eating, and Unrestricted Eating on Eating Patterns and Dietary Intake: Results from a Randomized Controlled Trial.

Lisa J Harnack, Niki Oldenburg, Qi Wang, Erika Helgeson, Abdisa Taddese, Nicole LaPage, Alison Alvear, Alison Wong, Michelle Hanson, Julie D Anderson, Brad P Yentzer, Douglas G Mashek, Emily N C Manoogian, Satchidananda Panda, Lisa S Chow.

BACKGROUND: Time-restricted eating (TRE) may be as effective as an energy-restricted (ER) diet for weight loss. But little is known about the effects of TRE on eating patterns and dietary intake.
OBJECTIVE: The aims of this study were to examine the relative effects of a TRE, ER, and unrestricted eating (UE) diet on eating patterns and dietary intake.
DESIGN: This study is a secondary analysis of data from a randomized controlled trial carried out between October 2020 and October 2023. Over this period 88 participants were randomized to a TRE, ER or UE diet group.
PARTICIPANTS/SETTING: Adults with obesity in the Minneapolis St Paul, Minnesota metropolitan area who completed study baseline and follow-up measures of dietary intake (n=73).
INTERVENTION: The interventions were: 1) TRE with an 8-hour self-chosen window with ad-libitum diet; 2) ER diet with 15% reduction of energy intake; or 3) unrestricted eating (UE) in which self-monitoring of food intake was encouraged with no specific change to eating recommended. The intervention period was 12 weeks.
MAIN OUTCOME MEASURES: Outcomes included meals eaten and intake of vegetables, fruit, dairy, protein foods, grains, energy, added sugars, saturated fat, sodium, dietary fiber and potassium.
STATISTICAL ANALYSES: Multivariate linear regression analyses were carried out to compare change in food and nutrient intake between experimental groups. Logistic mixed effects models were constructed to examine change in meals eaten.
RESULTS: The TRE group ate fewer daily meals at end-intervention (-1.1 meals/day; 95% CI: -1.6, -0.7) compared to baseline, whereas the ER and UE groups did not experience a change in eating occasions. Those in the TRE group were less likely to report eating breakfast during end-intervention compared to baseline (OR 0.13; 95% CI 0.05,0.33) whereas no statistically significant change in behavior was identified for the ER (OR 1.02; 95% CI 0.41,2.55) or UE (OR 0.68; 95% CI 0.28,1.68) groups. Between baseline and end-intervention those in the TRE group had a decrease in intake of energy (-469 kcal/day; 95% CI: -681,-257), saturated fat (-8.5 g/day; 95% CI:-12.9,-4.1), potassium (-496 mg/day; 95% CI: -729,-263), and total (-1.7 ounce equivalents/day; 95% CI: -2.9,-0.6) and refined grains (-1.6 ounce equivalents; 95% CI: -2.6,-0.6). These changes were more marked compared to changes in the UE group. There were no statistically significant differences found between those in the TRE and ER groups.
CONCLUSIONS: Findings suggest that TRE with an 8-hour window and ad libitum intake may have similar effects on food and nutrient intake as an energy-restricted diet.

Keywords: Time-restricted eating; calorie-restricted diet; diet quality; eating pattern; randomized trial

DOI: https://doi.org/10.1016/j.jand.2026.156331

Biol Methods Protoc. 2026 ;11(1): bpag014

One size does not fit all: A comparative framework for optimizing ribonucleic acid transfection across acute myeloid leukemia cell lines.

Monika M Kojic, Carmen Spencer, Olivia Kovecses, Maureen McKeague.

Robust transient knockdown strategies are critical to oligonucleotide therapeutic development, yet ineffective and variable RNA delivery across experimental models continues to limit target validation. Efficient delivery of nucleic acids into acute myeloid leukemia (AML) cells is particularly challenging due to their immature, suspension phenotype. Here, we performed a head-to-head benchmarking comparison of commonly used chemical transfection reagents (Lipofectamine 3000, Lipofectamine 2000, RNAiMAX, INTERFERin) alongside a physical electroporation approach (Lonza nucleofection) across four genetically distinct AML cell lines (THP-1, OCI-AML3, MV4-11, MOLM-14). To establish recommended RNA delivery strategies, we used small-interfering RNA (siRNA) and quantified functional knockdown by RT-qPCR, with protein-level validation and paired assessment of post-transfection viability. Lipid-based formulations were most effective in more differentiated AML cell lines (for example, THP-1 and OCI-AML3), whereas more immature lines (MV4-11 and MOLM-14) were poorly responsive to chemical transfection but efficiently transfected by electroporation. A short serum-free incubation period enhanced lipid-mediated delivery in permissive lines and produced measurable gains in more resistant models. Transfection-associated cytotoxicity was strongly method-dependent, with lipid-based reagents producing minimal to modest viability losses and nucleofection causing substantially greater short-term reductions in viable cell numbers. Based on this systematic comparison, most chemical reagents supported efficient delivery in THP-1 and, to a lesser extent, OCI-AML3, while MV4-11 and MOLM-14 demonstrated strict dependence on electroporation for meaningful intracellular uptake. Together, our results define a concise, qPCR-guided workflow, validated at the protein level, that provides a replicable, decision-oriented framework for selecting efficient and fit-for-purpose short RNA delivery strategies in AML cell lines.

Keywords: RNA delivery; lipid transfection; nucleic acid therapeutics; qPCR validation; siRNA transfection; suspension cells

DOI: https://doi.org/10.1093/biomethods/bpag014

Cancer Lett. 2026 Mar 17. pii: S0304-3835(26)00200-4. [Epub ahead of print] 218437

The Hallmarks of Pancreatic Cancer.

Laura E Kane, David Hackett, Rebecca Lyons, Barbara M Ryan, Stephen G Maher.

The hallmarks of cancer and enabling characteristics are widely regarded as the key features that best define malignant disease. In a process as intricate as the development of cancer, a simple definition or stepwise series of biological events does little to encapsulate the insurmountable complexity that is this disease. Indeed, over the course of the last 25 years alone, there have been four renditions of the "Hallmarks of Cancer", each attempting to encapsulate the mechanisms involved in the development of cancer by providing a list of strict criteria that must be met in order to define the disease. With each of these four sets of principles, modern research has caused the ensuing recapitulation to be revised, and without exception, to expand. In fact, what originally began as six hallmarks of cancer, has become a list of parameters that is fourteen strong, and which aim to summarize the functional capabilities that, when acquired by human cells, provides them with the ability to form a malignant, life-threatening tumour. While at present, these hallmark capabilities have largely been discussed in the context of all cancers, this review discusses each in the specific context of pancreatic cancer (PC). PC has the worst prognosis of all cancers globally, with late-stage diagnoses, aggressive tumour microenvironments, and limited treatment options contributing to the current 5-year survival rate of 13%. Here, we highlight PC-specific mechanisms underpinning each hallmark of cancer to provide a comprehensive review of the current state of knowledge around this complex disease, with the aim of aiding understanding and facilitating more meaningful research avenues.

DOI: https://doi.org/10.1016/j.canlet.2026.218437