Obesity is increasing rapidly worldwide and is accompanied by many complications, including impaired muscle regeneration. The obese condition is known to inhibit AMPK activity in multiple tissues. We ...hypothesized that the loss of AMPK activity is a major reason for hampered muscle regeneration in obese subjects. We found that obesity inhibits AMPK activity in regenerating muscle, which was associated with impeded satellite cell activation and impaired muscle regeneration. To test the mediatory role of AMPKα1, we knocked out AMPKα1 and found that both proliferation and differentiation of satellite cells are reduced after injury and that muscle regeneration is severely impeded, reminiscent of hampered muscle regeneration seen in obese subjects. Transplanted satellite cells with AMPKα1 deficiency had severely impaired myogenic capacity in regenerating muscle fibers. We also found that attenuated muscle regeneration in obese mice is rescued by AICAR, a drug that specifically activates AMPK, but AICAR treatment failed to improve muscle regeneration in obese mice with satellite cell-specific AMPKα1 knockout, demonstrating the importance of AMPKα1 in satellite cell activation and muscle regeneration. In summary, AMPKα1 is a key mediator linking obesity and impaired muscle regeneration, providing a convenient drug target to facilitate muscle regeneration in obese populations.
Dark berry fruits are one of the top 10 richest sources of dietary polyphenols and have been examined for their pharmacokinetic benefits in the human body related to absorption, digestion, ...metabolism, and excretion (ADME). With the expansion of the world wide web and rise of discretionary income in Europe and North America impacting the global food trade during the 21st century, several species of berries have become available for general consumption that may have previously been out of reach of the average consumer. Compared to their commercial counterparts, these berries contain many of the same polyphenols, and the possibility exists for the discovery of novel phenolic compounds that may affect the ADME process in a host‐beneficial way. Several species have demonstrated antioxidant, antiobesogenic, antimicrobial, and anti‐inflammatory properties through in vitro, animal studies, and human clinical trials. This review examines the available chemical compositions of several dark berries and their effect on the ADME process, their implication in host health effects, and the potential of these emerging species to suggest areas for future research.
Several species of dark berries have become available for general consumption which contain high levels of polyphenols. This review examines the available chemical compositions of several dark berries and their health effects, and the potential of these often under studied species to suggest areas for future research.
Leghemoglobins enable the endosymbiotic fixation of molecular nitrogen (N
) in legume nodules by channeling O
for bacterial respiration while maintaining a micro-oxic environment to protect O
...-sensitive nitrogenase. We found that the NIN-like protein (NLP) transcription factors NLP2 and NIN directly activate the expression of leghemoglobins through a promoter motif, resembling a “double” version of the nitrate-responsive elements (NREs) targeted by other NLPs, that has conserved orientation and position across legumes. CRISPR knockout of the NRE-like element resulted in strongly decreased expression of the associated leghemoglobin. Our findings indicate that the origins of the NLP-leghemoglobin module for O
buffering in nodules can be traced to an ancient pairing of NLPs with nonsymbiotic hemoglobins that function in hypoxia.
Most patients with KIT-mutant gastrointestinal stromal tumours (GISTs) benefit from imatinib, but treatment resistance results from outgrowth of heterogeneous subclones with KIT secondary mutations. ...Once resistance emerges, targeting KIT with tyrosine kinase inhibitors (TKIs) sunitinib and regorafenib provides clinical benefit, albeit of limited duration.
We systematically explored GIST resistance mechanisms to KIT-inhibitor TKIs that are either approved or under investigation in clinical trials: the studies draw upon GIST models and clinical trial correlative science. We subsequently modelled in vitro a rapid TKI alternation approach against subclonal heterogeneity.
Each of the KIT-inhibitor TKIs targets effectively only a subset of KIT secondary mutations in GIST. Regorafenib and sunitinib have complementary activity in that regorafenib primarily inhibits imatinib-resistance mutations in the activation loop, whereas sunitinib inhibits imatinib-resistance mutations in the ATP-binding pocket. We find that rapid alternation of sunitinib and regorafenib suppresses growth of polyclonal imatinib-resistant GIST more effectively than either agent as monotherapy.
Our data highlight that heterogeneity of KIT secondary mutations is the main mechanism of tumour progression to KIT inhibitors in imatinib-resistant GIST patients. Therapeutic combinations of TKIs with complementary activity against resistant mutations may be useful to suppress growth of polyclonal imatinib-resistance in GIST.
Amplifications and mutations in the KIT proto-oncogene in subsets of melanomas provide therapeutic opportunities.
We conducted a multicenter phase II trial of imatinib in metastatic mucosal, acral, ...or chronically sun-damaged (CSD) melanoma with KIT amplifications and/or mutations. Patients received imatinib 400 mg once per day or 400 mg twice per day if there was no initial response. Dose reductions were permitted for treatment-related toxicities. Additional oncogene mutation screening was performed by mass spectroscopy.
Twenty-five patients were enrolled (24 evaluable). Eight patients (33%) had tumors with KIT mutations, 11 (46%) with KIT amplifications, and five (21%) with both. Median follow-up was 10.6 months (range, 3.7 to 27.1 months). Best overall response rate (BORR) was 29% (21% excluding nonconfirmed responses) with a two-stage 95% CI of 13% to 51%. BORR was significantly greater than the hypothesized null of 5% and statistically significantly different by mutation status (7 of 13 or 54% KIT mutated v 0% KIT amplified only). There were no statistical differences in rates of progression or survival by mutation status or by melanoma site. The overall disease control rate was 50% but varied significantly by KIT mutation status (77% mutated v 18% amplified). Four patients harbored pretreatment NRAS mutations, and one patient acquired increased KIT amplification after treatment.
Melanomas that arise on mucosal, acral, or CSD skin should be assessed for KIT mutations. Imatinib can be effective when tumors harbor KIT mutations, but not if KIT is amplified only. NRAS mutations and KIT copy number gain may be mechanisms of therapeutic resistance to imatinib.
Almond are among the most consumed tree nuts and used in a variety of food products. Recent almond butter recalls due to potential contamination of
Listeria monocytogenes
highlight the need to ...control
L. monocytogenes
in almond products. The objectives of this study were to examine the stability of
L. monocytogenes
in almond meal during extended storage and analyze thermal resistance of
L. monocytogenes
in almond meal of controlled moisture contents or water activity (a
w
) using thermal death time (TDT) cells and thermal water activity (TWA) cells, respectively.
L. monocytogenes
maintained a stable population in almond meal for 44–48 weeks at 4°C regardless of a
w
; however, we observed about 1.69 and 2.14 log
10
colony-forming units (CFU)/g reduction of
L. monocytogenes
in a
w
0.25 and 0.45 almond meal over 44 to 48 weeks of storage at 22°C. Under all test conditions using either TDT or TWA cells, the inactivation kinetics of
L. monocytogenes
in almond meal fitted the log-linear model well; thermal resistance of
L. monocytogenes
in almond meal was inversely related to the a
w
of samples.
D
75
-/
D
80
-values of
L. monocytogenes
in a
w
0.25 and 0.45 almond meal obtained using TDT cells were 47.6/22.0 versus 17.2/11.0 min, respectively.
D
80
-,
D
85
-, and
D
90
-values of
L. monocytogenes
in a
w
0.25 almond meal obtained using TWA cells were 59.5 ± 2.1, 27.7 ± 0.7, and 13.2 ± 1.1 min, respectively, in contrast to 22.0 ± 1.1, 10.6 ± 0.2, and 4.6 ± 0.4 min obtained using TDT cells. The
z
-value of
L. monocytogenes
in a
w
0.25 almond meal was not affected by TWA and TDT cell type (15.4–15.5°C), whereas
z
-value of
L. monocytogenes
in a
w
0.45 almond meal was 10°C higher than that in a
w
0.25 almond meal. This study contributes to our understanding of
L. monocytogenes
in nuts and impacts of a
w
on the development of thermal resistance in low-moisture foods.
Scope
Enhancing the formation and function of brown adipose tissue (BAT) increases thermogenesis and hence reduces obesity. Thus, we investigate the effects of resveratrol (Resv) on brown adipocyte ...formation and function in mouse interscapular BAT (iBAT).
Methods and results
CD1 mice and stromal vascular cells (SVCs) isolated from iBAT were treated with Resv. Expression of brown adipogenic and thermogenic markers, and involvement of AMP‐activated protein kinase (AMPK)α1 were assessed. In vivo, Resv‐enhanced expression of brown adipogenic markers, PR domain‐containing 16 (PRDM16) and thermogenic genes, uncoupling protein 1 (UCP1) and cytochrome C in iBAT, along with smaller lipid droplets, elevated AMPKα activity and increased oxygen consumption. Meanwhile, Resv promoted expression of PRDM16, UCP1, PGC1α, cytochrome C and pyruvate dehydrogenase (PDH) in differentiated iBAT SVCs, suggesting that Resv enhanced brown adipocyte formation and function in vitro. In addition, Resv stimulated AMPKα and oxygen consumption in differentiated iBAT SVCs. However, the promotional effects of Resv were diminished by AMPK inhibition or AMPKα1 knockout, implying the involvement of AMPKα1 in this process.
Conclusion
Resv enhanced brown adipocyte formation and thermogenic function in mouse iBAT by promoting the expression of brown adipogenic markers via activating AMPKα1, which contributed to the anti‐obesity effects of Resv.
In vivo, dietary 0.1% Resv promoted brown adipogenesis markers, increased oxygen consumption, and activated AMPKα activity in iBAT. In vitro, 10 μM Resv elicited the same effects on differentiated iBAT SVCs. However, the promotional effects of Resv were abolished by AMPK inhibition or AMPKα1 KO. These data showed that Resv enhanced brown adipocyte formation and function by activating AMPKα1.
KIT is the major oncogenic driver of gastrointestinal stromal tumors (GIST). Imatinib, sunitinib, and regorafenib are approved therapies; however, efficacy is often limited by the acquisition of ...polyclonal secondary resistance mutations in KIT, with those located in the activation (A) loop (exons 17/18) being particularly problematic. Here, we explore the KIT-inhibitory activity of ponatinib in preclinical models and describe initial characterization of its activity in patients with GIST.
The cellular and in vivo activities of ponatinib, imatinib, sunitinib, and regorafenib against mutant KIT were evaluated using an accelerated mutagenesis assay and a panel of engineered and GIST-derived cell lines. The ponatinib-KIT costructure was also determined. The clinical activity of ponatinib was examined in three patients with GIST previously treated with all three FDA-approved agents.
In engineered and GIST-derived cell lines, ponatinib potently inhibited KIT exon 11 primary mutants and a range of secondary mutants, including those within the A-loop. Ponatinib also induced regression in engineered and GIST-derived tumor models containing these secondary mutations. In a mutagenesis screen, 40 nmol/L ponatinib was sufficient to suppress outgrowth of all secondary mutants except V654A, which was suppressed at 80 nmol/L. This inhibitory profile could be rationalized on the basis of structural analyses. Ponatinib (30 mg daily) displayed encouraging clinical activity in two of three patients with GIST.
Ponatinib possesses potent activity against most major clinically relevant KIT mutants and has demonstrated preliminary evidence of activity in patients with refractory GIST. These data strongly support further evaluation of ponatinib in patients with GIST.
Metastatic GI stromal tumor (GIST) is a life-threatening disease with no therapy of proven efficacy after failure of imatinib and sunitinib. Regorafenib is a structurally unique inhibitor of multiple ...cancer-associated kinases, including KIT and platelet-derived growth factor receptor (PDGFR), with broad-spectrum anticancer activity in preclinical and early-phase trials. Because KIT and PDGFR-α remain drivers of GIST after resistance to imatinib and sunitinib, we performed a multicenter single-stage phase II trial of regorafenib in patients with advanced GIST after failure of at least imatinib and sunitinib.
Patients received regorafenib orally, 160 mg daily, on days 1 to 21 of a 28-day cycle. Disease assessment was performed every two cycles per RECIST 1.1. Primary end point was clinical benefit rate (CBR), defined as objective responses (ie, complete or partial response PR as well as stable disease SD ≥ 16 weeks). Serial tumor biopsies were obtained from consenting patients whenever possible.
From February to December 2010, 34 patients were enrolled at four US centers. As of July 28, 2011, 33 patients had received at least two cycles of regorafenib (range, two to 17 cycles). CBR was 79% (95% CI, 61% to 91%). Four patients achieved PR, and 22 exhibited SD ≥ 16 weeks. Median progression-free survival was 10.0 months. The most common grade 3 toxicities were hypertension and hand-foot-skin reaction.
Regorafenib has significant activity in patients with advanced GIST after failure of both imatinib and sunitinib. A phase III trial of regorafenib versus placebo is ongoing to define more fully the safety and efficacy of regorafenib in this setting.
A highly sensitive surface plasmon resonance (SPR) sensor comprising a dual-core photonic crystal fiber (PCF) is designed to detect minute changes in analyte refractive indices (RIs) between 1.33 and ...1.42. In order to simplify the fabrication process and analytical protocol, a gold film is deposited on the external surface of the fiber to excite surface plasmon polaritons (SPPs). The larger diameter air holes are used in the photonic crystal fiber (PCF) cladding, which not only simplifies the actual production, but also makes the energy of the core more concentrated, and can more fully generate surface plasmon resonance with surface plasmon polaritons (SPPs). The dual-core PCF-SPR sensor is analyzed by the finite-element method (FEM), and the various structural parameters are investigated systematically and optimized. The optimized PCF-SPR sensor shows a maximum wavelength sensitivity of 29,500 nm/RIU and resolution of 3.39 × 10
−6
RIU.
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