Main Research Findings

1) Administration of CMS-121 was shown to reduce disease progression in an animal model of Huntington’s Disease.

1) CMS-121 has the potential to mitigate and treat metabolic disorders such as obesity and diabetes.

Selected Data
1) The study performed by the research team of Ates et al investigated whether CMS121, a chemically modified derivative of the flavonol fisetin, could slow disease progression in experimental models of Huntington’s disease (HD). The investigators selected CMS121 from a larger group of more than 160 synthetic fisetin derivatives because earlier work demonstrated that it retained several of fisetin’s potentially neuroprotective biological activities while possessing improved pharmacological properties. Fisetin had previously demonstrated beneficial effects in models of HD, Alzheimer’s disease, ischemic stroke, and other neurological disorders. The rationale for the present study was based on the complex pathology of HD, which involves abnormalities in transcription, protein processing, oxidative stress, mitochondrial function, inflammation, and other cellular processes. Because these processes involve multiple interacting pathways, the authors proposed that a compound with multiple biological effects might be more useful than a treatment directed against a single molecular target. CMS121 had previously demonstrated efficacy in models of Alzheimer’s disease and had favorable pharmacological characteristics, including good oral bioavailability and brain exposure. The current study therefore evaluated CMS121 in two established mouse models of HD, R6/2 and YAC128, with particular emphasis on motor function, body weight, lifespan, and molecular changes within the striatum [1].
The first experimental model was the R6/2 mouse, an aggressive model of HD characterized by the development of strong and rapidly progressive behavioral abnormalities. One week after arrival, baseline motor performance was assessed using both the open-field test and rotarod. The animals were then allocated to three treatment groups: a control diet, a diet containing 200 ppm CMS121, or a diet containing 400 ppm CMS121. The distribution procedure was designed so that the treatment groups did not differ in baseline motor performance before treatment began. CMS121 administration began at six weeks of age, following baseline testing. Motor performance was evaluated every two weeks using the rotarod and open-field tests, while body weight was recorded weekly. Forelimb and hindlimb grip strength was measured at 13 weeks. At approximately 14 weeks, six mice from each group were sacrificed, and their striata were collected for molecular analysis. The remaining animals continued to be followed for motor performance, body weight, and lifespan.
The second model was the YAC128 mouse, which produces a substantially slower and milder HD phenotype than R6/2 mice. Male hemizygous YAC128 mice expressing full-length human huntingtin gene with approximately 120 CAG repeats were studied alongside non-carrier controls. The YAC128 mice were randomly assigned to either control diet or 200 ppm CMS121 treatment. Each treatment group initially contained 15 mice, while 19 non-carrier mice served as controls. The groups were balanced so that there were no significant baseline differences in motor performance or body weight before treatment. Baseline motor testing was conducted shortly after the mice arrived, after which treatment began approximately one month later. Because the YAC128 model develops motor abnormalities much more slowly than R6/2 mice, motor function was evaluated at approximately seven, nine, thirteen, and eighteen months of age. Body weight was also monitored longitudinally. The researchers selected 200 ppm CMS121 for this model because that concentration had appeared more effective than 400 ppm in the R6/2 experiments with respect to motor dysfunction and lifespan. The use of the slower YAC128 model also allowed the investigators to examine the effects of CMS121 when treatment was initiated before obvious motor symptoms developed [1].
Several behavioral methods were used to characterize motor function. The rotarod assessed motor coordination, balance, and endurance. Before formal testing, animals underwent training consisting of three to four 60-second exposures at five revolutions per minute. During experimental trials, the rotarod accelerated from zero to 50 rpm over 180 seconds. Each mouse completed three trials separated by 15-minute intervals, and the latency to fall was recorded and averaged. The open-field test provided an assessment of spontaneous locomotor activity. Horizontal and vertical activity was recorded automatically for 30 minutes. Grip strength provided an additional assessment of neuromuscular function. Forelimb and hindlimb strength were measured separately using a grip-strength meter. Each mouse grasped a grid and was slowly pulled away from the sensor until it released the grid. Five measurements were obtained, and the mean force was calculated for each animal. These complementary assays allowed the investigators to evaluate coordination, spontaneous activity, and muscular strength rather than relying on a single behavioral outcome [1].
2) The study performed by Dafre et al investigated whether CMS121 could counteract age-associated weight gain and metabolic dysfunction in otherwise healthy wild-type mice. The study was motivated by previous findings showing that CMS121 improved glucose and lipid metabolism in leptin-receptor-deficient db/db obese mice and that it had beneficial effects on brain metabolism in models of aging and Alzheimer’s disease. The authors were particularly interested in CMS121 because previous work indicated that it inhibits fatty acid synthesis through effects involving fatty acid synthase (FASN) and acetyl-CoA carboxylase 1 (ACC1), thereby increasing the availability of acetyl-CoA. The present study extended this work to normal C57BL/6 mice to determine whether CMS121 could influence body composition, energy expenditure, glucose regulation, lipid metabolism, mitochondrial function, hepatic metabolism, inflammation, and circulating metabolites. The investigators specifically examined whether the metabolic effects of CMS121 resembled those produced by ketogenic diets, which are known to promote weight loss and alter glucose and lipid metabolism but can be difficult to maintain long term [2].
The principal experiment used male C57BL/6 mice beginning at five weeks of age. Twelve mice were randomly assigned to either a control diet or a standard rodent diet containing CMS121, and animals were housed three per cage. Treatment continued for six months, meaning that the mice were approximately seven months old when the experiment ended. Both diets were supplied ad libitum. Body weight and food consumption were monitored weekly throughout the study. Based on average cage food consumption, CMS121 exposure was estimated at approximately 9.4 mg/kg/day during the first 17 weeks, when the dietary concentration was 200 ppm, and approximately 18.8 mg/kg/day during weeks 18–24, when the concentration was increased to 400 ppm. The investigators therefore examined CMS121 exposure over an extended period rather than evaluating a short-term pharmacological response. Importantly, behavioral testing and data collection were performed by researchers blinded to treatment allocation, reducing the potential for observer bias. Body composition was evaluated at week 13, metabolic status was assessed at week 15, and the animals were sacrificed after six months for collection of blood, liver, and subcutaneous adipose tissue [2].
A variety of metabolic assessments were used to determine how CMS121 influenced body composition and energy expenditure. At week 13, the investigators used an EchoMRI 100 system to quantify body mass composition, including lean and fat mass. At week 15, mice were placed in metabolic cages for five days. Software systems allowed investigators to measure and analyze food and water consumption, locomotor activity, oxygen consumption, carbon dioxide production, respiratory exchange ratio (RER), and energy expenditure using indirect calorimetry. This approach enabled the reseatchers to distinguish changes in body weight from changes in metabolic activity and physical activity. The design was particularly relevant because a reduction in body weight could theoretically result simply from reduced food intake or increased movement; therefore, measuring oxygen consumption, carbon dioxide production, RER, and ambulatory activity provided additional information regarding the metabolic basis of the observed effects.
Glucose metabolism was assessed using several complementary measurements. Blood glucose was measured using enzymatic hexokinase-based assays or Accu-Chek Aviva test strips, depending on the sample. Glycated hemoglobin (HbA1c) was measured enzymatically, while insulin concentrations were determined using an ELISA. A glucose tolerance test (GTT) was conducted after overnight food deprivation. The mice received glucose by gavage at 0.5 g/kg, and blood glucose was subsequently measured at 0, 30, 60, 90, and 120 minutes through tail-vein sampling. Lipid metabolism was evaluated by measuring plasma and liver triglycerides, cholesterol, and free fatty acids. Plasma triglycerides and cholesterol were measured using commercial kits, liver cholesterol was measured fluorometrically, and free fatty acids were assessed using a fluorescent assay. At the end of the experiment, animals were anesthetized and blood was obtained by cardiac puncture [2].
The investigators then examined protein markers associated with mitochondrial function, glucose metabolism, lipid synthesis, and inflammation in adipose tissue and liver. The protein panel included Nrf1 and TFAM as markers of mitochondrial biogenesis; NDUFB8, SDHB, UQCRC2, and ATP5A as markers of mitochondrial respiratory complexes; TOM20 as a mitochondrial membrane marker; phosphorylated ACC1 and FASN as markers of lipid synthesis; GLUT4 as a glucose-transport marker; and several hepatic proteins associated with glycolysis, gluconeogenesis, TCA-cycle metabolism, and inflammation [2].

Discussion
1) The results of the study performed by Ates et al demonstrated that CMS121 partially slowed disease progression in both mouse models of Huntington’s disease, although its effects differed according to dose and disease model. In the R6/2 mice, treatment was administered at 200 or 400 ppm in the diet, corresponding to approximately 17 and 34 mg/kg/day, respectively. Importantly, the animals already demonstrated significant motor impairment at six weeks of age, before CMS121 treatment began. Rotarod performance was significantly worse in R6/2 mice than in non-carrier controls at baseline. Motor performance continued to deteriorate with age across all groups, producing a highly significant overall age effect. However, the pattern of decline differed according to treatment. Untreated R6/2 mice demonstrated significant deterioration between successive measurements, whereas CMS121-treated animals did not exhibit the same consistent decline. In particular, the untreated group showed a significant decline between 10 and 12 weeks of age, whereas this decline was not statistically significant within the CMS121 groups. These findings indicated that CMS121 did not eliminate the underlying motor phenotype but appeared to slow the rate at which motor function deteriorated [1].
CMS121 also influenced body weight and general physical condition in the R6/2 animals. The authors observed that body weight declined more slowly in treated mice than in untreated R6/2 mice, with the effect most pronounced in animals receiving 400 ppm CMS121. Routine visual observations further suggested improved overall health. Treated animals generally appeared healthier, were better groomed, and demonstrated greater movement within their cages than untreated R6/2 mice, including at approximately 14 weeks of age. Grip-strength testing at 13 weeks revealed a significant improvement in forelimb strength in mice receiving 200 ppm CMS121 compared with untreated R6/2 animals.
Survival analysis provided additional evidence that CMS121 could extend healthspan, although the effect was dose-dependent and did not reach conventional statistical significance in the R6/2 model. Among the 36 animals included in the survival analysis, the median survival of untreated R6/2 mice was 113 days. Treatment with 200 ppm CMS121 increased median survival to 134 days. The survival curves differed with a p-value of 0.067 using the Mantel-Cox test, corresponding to a confidence interval of approximately 93.3%. This result suggested a moderate tendency toward increased survival at the lower dose. In contrast, 400 ppm CMS121 did not produce the same lifespan benefit. Interestingly, this dose produced the clearest effect on slowing body-weight loss, illustrating that the dose producing the greatest effect on one outcome did not necessarily produce the greatest effect on another. The authors therefore concluded that CMS121 produced measurable but incomplete benefits in the aggressive R6/2 model [1].
Transcriptomic analysis demonstrated that CMS121 also influenced molecular abnormalities associated with HD in the striatum. At 14 weeks, untreated R6/2 mice displayed extensive gene-expression abnormalities compared with non-carrier controls. In comparison, CMS121 treatment at either 200 or 400 ppm altered approximately 10% of these disease-associated genes relative to untreated R6/2 mice. There was substantial overlap between the genes affected by the two doses, particularly among downregulated genes. Analysis of 292 genes altered by CMS121 demonstrated that many treatment-associated changes moved expression in the direction of the non-carrier controls. That being said, CMS121 did not simply produce an unrelated transcriptional response; it partially reversed gene-expression abnormalities produced by the HD genotype. The heat map presented on page 15 demonstrates this pattern, with treatment-associated expression profiles moving toward the non-carrier pattern.
Gene-set enrichment analysis identified oxidative phosphorylation and proteasome-related pathways as particularly responsive to CMS121. Untreated R6/2 mice showed reduced expression of numerous genes involved in oxidative phosphorylation, including 76 genes identified within this pathway. CMS121 increased expression of most of these genes, partially or almost completely restoring their levels toward those observed in non-carrier controls. The treatment also increased the overall expression of proteasomal genes. These findings were important because mitochondrial dysfunction and impaired protein homeostasis are recognized components of HD pathology. The authors therefore interpreted the transcriptomic results as evidence that CMS121 could partially normalize two major cellular processes disrupted by mutant huntingtin. Notably, the two CMS121 doses produced relatively similar transcriptomic effects despite differences in their effects on body weight, motor performance, and lifespan [1].

Figure 1: Changes in A) weight, B) grip strength, and C) survival following treatment with CMS-121.
The YAC128 experiments produced a somewhat different but complementary pattern. Because YAC128 mice develop a slower disease phenotype, CMS121 was administered at 200 ppm beginning during a presymptomatic period. There were no consistent differences in motor function between untreated YAC128 mice and non-carrier controls through approximately 12 months, demonstrating the slower progression of this model. Nevertheless, at nine months, CMS121-treated YAC128 mice exhibited significantly greater forelimb grip strength than untreated animals. At seven and nine months, however, open-field testing showed relatively little difference between treatment groups, and CMS121-treated mice unexpectedly tended to perform worse on several open-field parameters. This suggests that the beneficial effects of CMS121 were not immediately apparent across all motor measures. Continued monitoring revealed stronger treatment effects at later ages. At 13 months, CMS121-treated mice had significantly greater forelimb and hindlimb grip strength, while at 18 months, hindlimb strength remained significantly improved.
The most pronounced behavioral benefits in YAC128 mice appeared at 18 months. At this age, CMS121-treated mice performed significantly better on nearly all measured open-field parameters. They traveled farther, moved more frequently, and spent less time resting than untreated YAC128 animals. Thus, unlike the relatively subtle findings at seven and nine months, the beneficial effect of CMS121 became increasingly evident as the mice aged. This age-dependent pattern was one of the important findings of the study because it suggested that CMS121 may be particularly useful for maintaining motor function during later stages of disease progression. The page 18 figure documents the early grip-strength and open-field findings, while the page 19 figure demonstrates the stronger motor effects at 13 and 18 months. [1]
Finally, CMS121 produced a meaningful improvement in median lifespan in YAC128 mice. Median survival increased from approximately 540 days in untreated YAC128 mice to 631 days in CMS121-treated mice, representing a 17% increase in median lifespan. Untreated YAC128 mice had a significantly shorter median lifespan than non-carrier controls, whereas the median lifespan of CMS121-treated YAC128 mice was no longer significantly different from that of the non-carrier controls. CMS121 did not, however, increase maximum lifespan, indicating that the compound delayed disease-associated deterioration rather than completely preventing late-stage mortality. Unlike R6/2 mice, YAC128 animals gained rather than lost body weight during disease progression, and CMS121 did not significantly affect their body weight. The survival curves shown on page 20 demonstrate this normalization of median survival, with median survival values of approximately 642 days for wild-type controls, 631 days for CMS121-treated YAC128 mice, and 549 days for untreated YAC128 mice in the figure presentation [1].
2) The results of the study completed by Dafre et al demonstrated that long-term CMS121 administration substantially altered body composition and metabolic physiology in wild-type C57BL/6 mice. The researchers first found that food consumption was slightly lower in CMS121-treated mice, with linear regression demonstrating a significant difference between the treatment groups. However, the magnitude of the reduction in body-weight gain was considerably greater than could be explained by the relatively modest difference in food intake. Control mice increased from approximately 29.2 g at five weeks of age to 48.0 g after six months, corresponding to an average weight gain of 18.8 g. CMS121-treated mice increased from 27.61.3 g to 41.1 g, corresponding to a weight gain of only 13.4g. Thus, CMS121 reduced weight gain by approximately 40%. Importantly, the CMS121 group did not simply become smaller overall; these mice also possessed significantly greater lean mass and significantly less fat mass [2].
CMS121 also increased measures of metabolic activity. Indirect calorimetry demonstrated significantly higher oxygen consumption and carbon dioxide production in treated animals, whereas the respiratory exchange ratio was not significantly altered. Overall locomotor activity in the metabolic cages was also not significantly different between groups. Consequently, the increase in energy expenditure could not be definitively attributed to greater physical activity. The authors noted that the metabolic-cage assessment involved relatively few animals and could itself have been stressful, limiting interpretation of the locomotor findings. They also reported that an earlier open-field assessment conducted two weeks after introduction of the diet showed increased locomotor activity in CMS121-treated mice, although no later open-field measurement was available to establish whether that effect persisted. Taken together, the body-composition and calorimetry findings suggested that CMS121 promoted a metabolic state characterized by reduced fat accumulation, greater lean mass, and increased basal metabolic activity [2].

Figure 2: Changes in nutrition, body mass, locomotion, and metabolism following treatment with CMS-121.
Glucose measurements generally indicated an improvement in glycemic status, although not every outcome reached statistical significance. During the GTT, CMS121-treated mice tended to have lower glucose concentrations, with the clearest statistically significant difference occurring at 60 minutes. The overall glucose area under the curve was lower in the CMS121 group but did not reach statistical significance. Fasting blood glucose also tended to be lower in treated animals, while glucose measured under fed conditions was not significantly different. HbA1c showed a tendency toward reduction, suggesting an overall improvement in longer-term glycemic exposure. The most pronounced glucose-related finding was the marked reduction in circulating insulin, which reached statistical significance. Thus, CMS121 appeared to improve glucose handling while requiring substantially less insulin. The authors suggested that the increased adipose-tissue GLUT4 expression observed later in the study could contribute to enhanced glucose uptake and insulin sensitivity [2].

Figure 3: Changes in blood glucose parameters following administration of CMS-121.
CMS121 also produced substantial changes in lipid metabolism. Plasma free fatty acids were significantly reduced, while plasma triglycerides remained approximately unchanged. Interestingly, plasma cholesterol increased significantly. In the liver, both free fatty acids and triglycerides were significantly reduced, whereas hepatic cholesterol was not significantly altered. Figure 3 provides a direct visual comparison of these lipid outcomes, showing reductions in plasma FFA, hepatic FFA, and hepatic triglycerides. These findings were interpreted as evidence for reduced lipid accumulation and altered fatty-acid handling rather than a uniform reduction in all circulating lipids. The combination of reduced liver triglycerides, lower free fatty acids, increased lean mass, and decreased fat mass suggested that CMS121 substantially remodeled lipid metabolism in peripheral tissues.
The adipose-tissue protein analyses provided evidence for enhanced mitochondrial biogenesis and altered glucose and lipid metabolism. CMS121 significantly increased the mitochondrial biogenesis-associated transcription factors Nrf1 and TFAM. There were also tendencies toward increased levels of respiratory-chain complexes I, II, III, and V, suggesting enhanced mitochondrial capacity. TOM20, a marker associated with the mitochondrial outer membrane, was significantly increased. At the same time, phosphorylation of ACC1 was increased. Because phosphorylation inhibits ACC1 activity, this finding was consistent with reduced conversion of acetyl-CoA into malonyl-CoA and therefore reduced fatty-acid synthesis. GLUT4 levels were also significantly increased in adipose tissue. These findings suggest that CMS121 increased mitochondrial biogenesis while simultaneously suppressing adipose lipogenesis and increasing the machinery available for glucose uptake [2].
The liver also displayed a complementary pattern of metabolic remodeling. CMS121 reduced FASN, supporting inhibition of de novo fatty-acid synthesis. PEPCK, a marker of gluconeogenesis, was also reduced, suggesting diminished hepatic gluconeogenesis. Increased PFKFB3 was interpreted as evidence for increased glycolytic flux, while decreased TXNIP could favor glucose uptake by reducing removal of glucose transporters from the plasma membrane. CMS121 also reduced hepatic MLYCD and protein malonylation, while fumarate hydratase (FH) levels decreased. The authors noted that the combination of decreased FASN, reduced PEPCK, increased PFKFB3, and altered TXNIP suggested a complex metabolic shift toward greater glucose utilization and reduced lipid synthesis. However, mitochondrial respiratory-chain markers in the liver were not significantly changed, despite an increase in TOM20. Therefore, unlike adipose tissue, the liver did not show a broad increase in respiratory-complex proteins.
Overall, the study demonstrated that CMS121 produced broad metabolic effects in aging wild-type mice, including approximately 40% less body-weight gain, greater lean mass, reduced fat mass, increased metabolic activity, improved insulin and glucose profiles, reduced circulating and hepatic free fatty acids, reduced hepatic triglycerides, enhanced adipose mitochondrial markers, increased GLUT4, suppression of lipid synthesis, and reduced hepatic inflammatory markers. The metabolomic findings further suggested a shift toward increased fatty-acid oxidation and ketogenic metabolism. The authors proposed that inhibition of FASN and activation of AMPK-associated ACC1 phosphorylation may increase acetyl-CoA availability and redirect metabolism away from de novo lipogenesis. They concluded that this metabolic remodeling could potentially contribute not only to peripheral metabolic health but also to the previously observed neuroprotective effects of CMS121 [2].

Disclaimer

**LAB USE ONLY**
*This information is for educational purposes only and does not constitute medical advice. THE PRODUCTS DESCRIBED HEREIN ARE FOR RESEARCH USE ONLY. All clinical research must be conducted with oversight from the appropriate Institutional Review Board (IRB). All preclinical research must be conducted with oversight from the appropriate Institutional Animal Care and Use Committee (IACUC) following the guidelines of the Animal Welfare Act (AWA).

Citations

[1] Ates G, Taguchi T, Maher P. CMS121 Partially Attenuates Disease Progression in Mouse Models of Huntington’s Disease. Mol Neurobiol. 2024;61(4):2165-2175. doi:10.1007/s12035-023-03711-2

[2] Dafre AL, Zahid S, Probst JJ, et al. CMS121: a novel approach to mitigate aging-related obesity and metabolic dysfunction. Aging (Albany NY). 2024;16(6):4980-4999. doi:10.18632/aging.205673

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