Biology subjects

Carnero, E. A.

Publications and source records attributed to Carnero, E. A..

4 recordsLinked to original sources

bioRxiv2026

Molecular Transducers of Physical Activity Consortium (MoTrPAC): Initial Insights into the Dynamic Human Responses to Exercise

The goal of the Molecular Transducers of Physical Activity Consortium (MoTrPAC) is to examine the physiological and molecular basis for health benefits in response to acute and chronic exercise. Prior to COVID-19 suspension, healthy, sedentary participants (N=206, 18-74y) were randomized to endurance exercise (N=80), resistance exercise (N=81), or non-exercise control (N=45) interventions. The prescribed vigorous acute endurance and resistance exercise bouts induced physiological and metabolic perturbations relative to resting homeostasis. The supervised chronic (3d/wk, 12wk) endurance or resistance training programs robustly improved several physiological parameters (i.e., VO2peak, muscular strength). Temporal biospecimen (blood, muscle, and adipose) collections and processing coupled to the acute exercise bouts were highly successful. In most cases, over 90% success was achieved for blood, muscle, and adipose samples. Endurance and resistance exercise induced distinct acute and chronic physiological responses, which provide a framework to interrogate the molecular basis for health adaptations to these two popular exercise modalities. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/705347v1_ufig1.gif" ALT="Figure 1"> View larger version (65K): org.highwire.dtl.DTLVardef@554ee9org.highwire.dtl.DTLVardef@afb28dorg.highwire.dtl.DTLVardef@f381cdorg.highwire.dtl.DTLVardef@cef19c_HPS_FORMAT_FIGEXP M_FIG C_FIG

systems biology↗

bioRxiv2025

Microbial Feast or Famine: dietary carbohydrate composition and gut microbiota metabolic function

Diet composition plays a major role in shaping the structure and function of the gut microbiota and influencing host health. While numerous studies have investigated the impact of macronutrient type and quantity on microbiota using in vitro systems, animal models, and human participants, most of these studies focused primarily on microbial-community composition and lacked the functional information that can be gained from transcript-level analyses. In this exploratory analysis, we use metatranscriptomic data to gain a functional perspective on how dietary composition is associated with the gut microbiota and hypothesized implications for host physiology. Data were derived from a tightly controlled, randomized cross-over feeding study conducted in a metabolic ward, where participants consumed two isocaloric and eucaloric diets differing in food processing and fiber content: A Western Diet (WD) limited in fiber, resistant starch, and whole foods and a Microbiome Enhancer Diet (MBD) composed of fiber-rich, whole foods. Our prior findings showed that a WD lead to a resource-limited microbiota enriched in mucin-degrading bacteria that resorted to metabolizing host-derived organic material, while the MBD supported a resource-replete microbiota that primarily metabolized dietary fiber. The objective of this work was to explore these findings more deeply using bioinformatic analyses of metatranscriptomic data. Our analysis showed increased transcription of fiber-degrading enzymes in the MBD and mucin-degrading enzymes in the WD. While in this analysis functional diversity of the gut microbiome was not affected, differences in resistant-starch and fiber content shifted the types of metabolic processes being actively transcribed. The MBD promoted biosynthetic and carbohydrate-fermenting pathways, while the WD was characterized by enzymes for host-glycan and protein degradation. Furthermore, the MBD-supported ecosystem benefits host health via enhanced SCFA production and reduced reliance on host glycan degradation. The WD fostered increased mucin and protein breakdown pathways that yield metabolites that may harm the gut barrier and systemic metabolism.

microbiology↗

bioRxiv2025

Methanogens are associated with altered microbial production of short-chain fatty acids and human-host metabolizable energy

Methanogens are CH4-producing, H2-oxidizing (i.e. hydrogenotrophic) archaea. Numerous studies have associated methanogens with obesity, but these results have been inconsistent. One link to host metabolism may be methanogens ability to consume H2, thus reducing H2 partial pressure and thermodynamically enhancing fermentation of sugars to short-chain fatty acids (SCFA) that the host can absorb. Because research linking methanogenesis to human metabolism is limited, our goal with this exploratory analysis was to investigate relationships between methanogens and other hydrogenotrophs, and the association of methanogens with human metabolizable energy (ME). Using results from a randomized crossover feeding study with well-characterized human participants and novel continuous methane measurements, we analyzed hydrogenotroph abundance and activity, fecal and serum SCFAs, and host ME between high and low CH4 producers. Methanogens were detected in about one-half of participants, and most were high CH4 producers. We found no evidence that methanogens consumption of H2 to produce CH4 affected other hydrogenotrophs. High CH4 producers had greater serum propionate and host ME irrespective of diet, as well as greater gene and transcript abundance of a key enzyme of the H2-consuming, propionate-producing succinate pathway. Finally, a network analysis revealed positive relationships between Methanobrevibacter smithii (the most prevalent methanogen in the human colon) and bacteria capable of degrading fiber and fermenting fiber- degradation products, thus forming a trophic chain to extract additional energy from undigested substrates. Our results show that methanogens in a microbial consortium were linked to host metabolizable energy through enhanced SCFA production and host SCFA absorption.

microbiology↗

bioRxiv2017

Physical activity unveils the relationship between mitochondrial energetics, muscle quality and physical function in older adults

BackgroundThe concept of mitochondrial dysfunction in aging muscle is highly controversial. In addition, emerging evidence suggests that reduced muscle oxidative capacity and efficiency underlie the etiology of mobility loss in older adults. Here, we hypothesized that studying well phenotyped older cohorts across a wide range of physical activity would unveil a range of mitochondrial function in skeletal muscle and in turn allow us to more clearly examine the impact of age per se on mitochondrial energetics. This also enabled us to more clearly define the relationships between mitochondrial energetics and muscle lipid content with clinically relevant assessments of muscle and physical function.\n\nMethodsThirty-nine volunteers were recruited to the following study groups; Young Active (YA, n=2F/8M, age=31.2{+/-}5.4 yrs.). Older Active (OA, n=2F/8M, age=67.5{+/-}2.7 yrs.) and Older Sedentary (OS, n=8F/11M, age=70.7{+/-}4.7 yrs.). Participants completed a graded exercise test to determine fitness (VO2peak), a submaximal exercise test to determine exercise efficiency, and daily physical activity (PA) was recorded using a tri-axial armband accelerometer. Mitochondrial energetics were determined by 1) 31P magnetic resonance spectroscopy and 2) respirometry of fiber bundles from vastus lateralis biopsies. Quadriceps function was assessed by isokinetic dynamometry and physical function by the short physical performance battery (SPPB) and stair climb test.\n\nResultsDaily PA energy expenditure was significantly lower in OS, compared to YA and OA groups. Despite fitness being higher in YA compared to OA and OS, mitochondrial respiration, ATPMax, P/O ratio and exercise efficiency were similar in YA and OA groups and were significantly lower in OS. P/O ratio was correlated with exercise efficiency. Time to complete the stair climb and repeated chair stand tests was significantly greater for OS. Interestingly, ATPMax was related to muscle contractile performance and physical function.\n\nConclusionsOlder adults who maintain a high amount of physical activity have better mitochondrial capacity, similar to highly active younger adults, and this is related to their better muscle quality, exercise efficiency and physical performance. This suggests that mitochondria could be an important therapeutic target for sedentary aging associated conditions including sarcopenia, dynapenia and loss of physical function.

physiology↗