In some muscle diseases, such as muscular dystrophy, exercise can increase muscle damage and alter myofiber adaptation. We determined whether this is also true for the congenital muscle disease ...nemaline myopathy using our mouse model of this disease. Nemaline mice expressing a mutant α‐tropomyosinslow protein α‐Tmslow(Met9Arg) in skeletal muscle underwent 4 weeks of treadmill exercise. Exercise increased slow/oxidative myofibers, but different fibers were involved in these transformations in nemaline mice. Despite similar expression of the mutant α‐Tmslow protein in muscles of the nemaline mouse, muscles responded in a unique manner that did not reflect fiber‐type composition. For example, the particular fibers involved in fast‐to‐slow transformation were specific for each muscle examined. In contrast to the muscular dystrophies, exercise did not result in muscle damage nor did it cause an increase in rod‐containing fibers; however, the fiber‐type distribution of rod‐containing fibers was altered in a muscle‐specific fashion. That exercise did not exacerbate the pathology (i.e., nemaline rod formation) supports its use in nemaline myopathy patients. This study shows that fibers of a similar type respond to increased activity differently in different muscles and suggests that fibers of similar type may be functionally distinct in different muscles. Muscle Nerve 30: 470–480, 2004
Abstract
Tumor hypoxia is prevalent in head and neck squamous cell carcinoma (HNSCC), where it limits radiotherapy outcomes. Hypoxia-activated prodrugs (HAPs) have been developed to target hypoxic ...regions of tumors. These agents undergo oxygen-sensitive reductive activation, thereby delivering cytotoxic species within hypoxic cells. This study investigated the efficacy and sensitivity determinants of the clinical-stage HAP evofosfamide (TH-302) using molecularly-characterized models of HNSCC. We deployed a collection of 27 HPV-negative HNSCC cell lines derived from lesions of varying TNM stages and primary, nodal or recurrent sites. The collection was characterized for gene expression by RNA-seq, from which somatic variants were also called. Their transcriptomic features were investigated in the context of pan-cancer TCGA data by hierarchical clustering. The potency and hypoxic selectivity of 3 HAPs - evofosfamide, PR-104A and SN30000 - were assessed by antiproliferative assay in 22 lines and compared to bromo-isophosphoramide mustard (Br-IPM), cisplatin and 5-FU. The antitumor activity of evofosfamide (50 mg/kg qdx5 for 2-3 cycles with or without a single 10 Gy dose of radiation on day 5 of cycle 1) was evaluated in HNSCC xenografts in addition to a PDX isolated from an SCC of the glottic larynx. The hypoxic fraction at baseline and after 5 days of treatment was quantified by pimonidazole staining. Genetic modifiers of sensitivity to evofosfamide and its cytotoxic metabolite Br-IPM were explored through whole-genome CRISPR-Cas9 screens using the GeCKO v2 library. High-throughput screens with a custom shRNA pool were performed in one HNSCC and two pancreatic ductal adenocarcinoma cell lines to identify reductases responsible for the activation of evofosfamide in hypoxic cells. Evofosfamide was more potent and more selective for hypoxic HNSCC cells in vitro than PR-104A or SN30000. Cell line sensitivity to evofosfamide was correlated with Br-IPM and cisplatin but not with PR-104A, SN30000 or 5-FU, indicating distinct sensitivity determinants. Evidence of antitumor activity with evofosfamide was observed in vivo. CRISPR screens identified potential evofosfamide sensitivity genes that were reproducibly enriched following drug exposure. Reductase-focused RNA interference screens defined a cluster of sensitivity genes that mapped to mitochondrial electron transport, whereas shRNA’s targeted against presumed activating enzymes such as POR were not enriched. Concentration-dependent oxidation of cytochrome a and decreased respiration was observed in cells exposed to evofosfamide, suggesting reduction by mitochondrial complexes. This study provides a rationale for the clinical evaluation of evofosfamide with radiotherapy in genetically defined subsets of HNSCC patients.
Citation Format: Francis W. Hunter, Avik Shome, Dan Li, Way W. Wong, Peter Tsai, Nooriyah Poonawala, Purvi M. Kakadiya, Troy M. Ketelä, Maria K. Kondratyev, Courtney R. Lynch, Tet-Woo Lee, Khanh B. Tran, Jules B. Devaux, Rachel Zussman, Cho R. Hong, Dennis Kee, Andrew M. Macann, Anthony J. Hickey, Stefan K. Bohlander, Cristin G. Print, William R. Wilson, Bradly G. Wouters, Stephen M. Jamieson. Preclinical efficacy and sensitivity determinants of evofosfamide in molecularly defined models of head and neck squamous cell carcinoma abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 169. doi:10.1158/1538-7445.AM2017-169
1 Department of Surgery, Royal North Shore Hospital,
University of Sydney, St. Leonards, New South Wales 2065; and
2 School of Exercise and Sport Science, University
of Sydney, Lidcombe, New South ...Wales 1825, Australia
Both exercise and insulin-like
growth factor I (IGF-I) are known to have major hypertrophic effects in
skeletal muscle; however, the interactive effect of exogenous IGF-I and
exercise on muscle protein turnover or the ubiquitin-proteasome pathway
has not been reported. In the present study, we have examined
the interaction between endurance exercise training and IGF-I treatment
on muscle protein turnover and the ubiquitin-proteasome pathway in the
postexercise period. Adult male rats (270-280 g) were randomized
to receive 5 consecutive days of progressive treadmill exercise and/or
IGF-I treatment (1 mg · kg body
wt 1 · day 1 ). Twenty-four hours
after the last bout of exercise, the rate of protein breakdown in
incubated muscles was significantly reduced compared with that in
unexercised rats. This was associated with a significant reduction in
the chymotrypsin-like activity of the proteasome and the rate of
ubiquitin-proteasome-dependent casein hydrolysis in muscle extracts
from exercised compared with unexercised rats. In contrast, the
muscle expression of the 20S proteasome subunit -1, ubiquitin, and
the 14-kDa E2 ubiquitin-conjugating enzyme was not altered by
exercise or IGF-I treatment 24 h postexercise. Exercise had no
effect on the rates of total mixed muscle protein synthesis in
incubated muscles 24 h postexercise. IGF-I treatment had no effect
on muscle weights or the rates of protein turnover 24 h after
endurance exercise. These results suggest that a suppression of the
ubiquitin-proteasome proteolytic pathway after endurance exercise may
contribute to the acute postexercise net protein gain.
protein synthesis; protein degradation; insulin-like growth factor
I; muscle adaptation
Abstract
Objective
The Consortium for Clinical Characterization of COVID-19 by EHR (4CE) is an international collaboration addressing coronavirus disease 2019 (COVID-19) with federated analyses of ...electronic health record (EHR) data. We sought to develop and validate a computable phenotype for COVID-19 severity.
Materials and Methods
Twelve 4CE sites participated. First, we developed an EHR-based severity phenotype consisting of 6 code classes, and we validated it on patient hospitalization data from the 12 4CE clinical sites against the outcomes of intensive care unit (ICU) admission and/or death. We also piloted an alternative machine learning approach and compared selected predictors of severity with the 4CE phenotype at 1 site.
Results
The full 4CE severity phenotype had pooled sensitivity of 0.73 and specificity 0.83 for the combined outcome of ICU admission and/or death. The sensitivity of individual code categories for acuity had high variability—up to 0.65 across sites. At one pilot site, the expert-derived phenotype had mean area under the curve of 0.903 (95% confidence interval, 0.886-0.921), compared with an area under the curve of 0.956 (95% confidence interval, 0.952-0.959) for the machine learning approach. Billing codes were poor proxies of ICU admission, with as low as 49% precision and recall compared with chart review.
Discussion
We developed a severity phenotype using 6 code classes that proved resilient to coding variability across international institutions. In contrast, machine learning approaches may overfit hospital-specific orders. Manual chart review revealed discrepancies even in the gold-standard outcomes, possibly owing to heterogeneous pandemic conditions.
Conclusions
We developed an EHR-based severity phenotype for COVID-19 in hospitalized patients and validated it at 12 international sites.
The Kentucky wheat (Triticum aestivum L.) crop is always at risk for Fusarium head blight (FHB) because of the prevalent grain crop rotation used by farmers. Corn (Zea mays L.) is followed by wheat, ...which is followed by double‐crop soybean Glycine max (L.) Merr.. The wheat crop is planted directly into corn stubble that harbors the causal fungus for FHB, Fusarium graminearum Schwabe. Therefore, developing FHB‐resistant winter wheat cultivars is a major goal of the wheat breeding program in Kentucky. ‘Pembroke 2014’ (Reg. No. CV‐1113, PI 675564) is an early maturing, semidwarf soft red winter wheat cultivar developed and released in 2014 by the Kentucky Agricultural Experiment Station for the combination of resistance to FHB, high yield potential, excellent test weight, and resistance to lodging. Pembroke 2014 was developed from the cross ‘25R18’/KY92C‐0010‐17//KY96C‐0767‐1. 25R18 is a soft red winter wheat cultivar with FHB resistance that likely traces to ‘Sumai 3’ or one of its derivatives. KY92C‐0010‐17 is a breeding line derived from the cross T63/VA85‐54‐290. KY96C‐0767‐1 is derived from the cross ‘2552’/VA92‐51‐12. The cross was made in 2003, and Pembroke 2014 was initially selected from F4:5 headrows in 2008 using a modified bulk breeding method. Selected rows that gave rise to Pembroke 2014, tested as KY03C‐1237‐32, carried the resistance allele at a major FHB resistance quantitative trait locus, Fhb1. Pembroke 2014 was extensively tested in multilocation replicated yield trials, the Uniform Eastern Soft Red Winter Wheat Nursery, the Uniform Northern Scab Nursery, and the Kentucky Wheat Variety Trial.
Background & aims: Methods of nutritional management in abdominal sepsis remain controversial.
Methods: Sprague Dawley rats were either fed via a central line in the right internal jugular vein or ...duodenally via a gastrostomy tube, and were randomised to undergo either caecal ligation and puncture (CLP) or laparotomy only. Post-operatively, animals received either parenteral nutrition, enteral nutrition or saline only (parenteral and enteral nutrition protocols were isocaloric and isonitrogenous). After 72
h, fractional rate of protein synthesis (
K
s, %/day) was measured in gastrocnemius muscle and liver, and protein breakdown was measured in incubated epitrochlearis muscles. Serum insulin-like growth factor-I (IGF-I), acid-labile subunit (ALS) and IGF binding protein-1 (IGFBP-1) levels were determined by specific radioimmunoassay methods.
Results: After CLP, when compared with starved animals, only enteral nutrition resulted in a significant decrease in survival to 72
h (
P<0.001). Parenteral nutrition, but not enteral nutrition, increased muscle (
P=0.02) and liver (
P<0.001)
K
s, IGF-I (
P<0.001) and ALS levels (
P<0.001), whereas both parenteral and enteral nutrition reduced IGFBP-1 levels (
P<0.001). Neither enteral nor parenteral nutrition reduced protein breakdown in septic animals.
Conclusions: In this model of severe abdominal sepsis where gut function cannot be assessed, enteral nutrition was associated with increased mortality and was less effective than parenteral nutrition in augmenting muscle and liver protein synthesis.
1 Department of Surgery, University of Sydney, and
2 The Kolling Institute of Medical Research, Royal North
Shore Hospital, Sydney, New South Wales 2065, Australia
Our aim was to
investigate the ...effects of modifying the carbohydrate-to-lipid ratio of
parenteral nutrition (PN) on body composition and the anabolic actions
of insulin-like growth factor I (IGF-I) and growth hormone (GH).
Adolescent male Sprague-Dawley rats were randomized to receive 7 days
of GH, IGF-I (3.5 mg · kg 1 · day 1 for both)
or placebo while receiving high-carbohydrate PN (CHO-PN), high-lipid PN
(L-PN), or an oral diet (chow) (the PN protocols were isonitrogenous
and isocaloric). PN impaired muscle growth, which was reversed by GH in
the CHO-PN group only ( P < 0.03). PN increased carcass
lipid ( P < 0.02), the effect being greater in the L-PN
than in the CHO-PN group ( P < 0.001). Visceral lean tissue growth was significantly impaired by PN ( P < 0.001). IGF-I reversed this impairment, but GH had no effect. PN
impaired the normal increase in hepatic protein and DNA
( P < 0.001) and produced liver steatosis
( P < 0.001). However, this steatosis was less in L-PN
than in CHO-PN ( P < 0.001). Serum IGF-I and the
acid-labile subunit (ALS) were decreased by PN ( P < 0.001) and were not affected by GH during PN treatment. However, GH
significantly increased serum ALS concentrations in the chow-fed rats
( P = 0.032). In conclusion, modifying the CHO-to-L
ratio of PN had no significant effect on IGF-I action, but CHO-PN
increased the peripheral effect of GH. L-PN increased carcass lipid
significantly and decreased hepatic steatosis. Nevertheless, PN caused
significant liver steatosis and profound impairment of hepatic cell
growth, which was associated with relative hepatic GH resistance.
growth hormone; parenteral nutrition; organ composition; body
composition; insulin-like growth factor I treatment; steatosis; liver
impairment
1 Department of Surgery,
University of Sydney, and 2 The
Kolling Institute of Medical Research, Royal North Shore Hospital,
Sydney, New South Wales 2065, Australia
The anabolic properties of ...insulin-like growth factor (IGF) I
are attenuated by oral diets that are low in protein. However, it is
not known whether parenteral nutrition (PN) providing a low amino acid
(AA) input will influence IGF-I action. With the use of a rat model,
this study examined the interaction between AA input (1.27 and 0.62 g
N · kg body
wt 1 · 24 h 1 , AA and 1/2AA
groups, respectively) and recombinant human IGF-I (rhIGF-I, 2.5 mg · kg body
wt 1 · 24 h 1 ) infusion on the
composition of the carcass and organs and on plasma insulin, IGF-I,
IGF-binding protein 1 (IGFBP-1), and acid-labile subunit (ALS)
concentrations. Carcass protein deposition only occurred in the AA
groups ( P < 0.003) and was not
influenced by administration of rhIGF-I. However, visceral protein loss
persisted in the AA group but was prevented by rhIGF-I infusion. The
changes in water content of the carcass and the organs were generally in the expected proportion of normal lean tissue. The accumulation of
lipid that follows the infusion of the AA-deficient PN was prevented by
rhIGF-I infusion, which may indicate an improved energy utilization.
Neither serum insulin nor ALS concentrations were influenced by the
level of AA infusion but were reduced by rhIGF-I administration.
However, plasma IGF-I levels were elevated by higher AA infusion and by
IGF-I administration. Also, IGFBP-1 concentrations were reduced by the
higher AA infusion and increased with rhIGF-I administration.
Interestingly, there was a significant interaction effect between both
of these influences. It is concluded that free IGF-I concentration,
which may be regulated by IGFBP-1 through a direct effect of AAs on the
liver, may have an important role in regulating anabolism in visceral
and possibly skeletal tissue during PN.
parenteral nutrition; insulin-like growth factor I administration; body composition; organ composition; insulin-like growth factor-binding
proteins
To determine whether the addition of tyrosine and arginine (Arg), as tyrosyl-arginine (TyrArg), to parenteral nutrition (PN) can promote anabolism, rats were assigned to: 1) PN (1.20 MJ · kg body ...weight BW
−1 · d
−1 and 1.22 gN · kgBW
−1 · d
−1; PN control group,
n = 5), 2) PN plus TyrArg (2.6 mmol · kgBW
−1 · d
−1; TyrArg group,
n = 6), or 3) PN plus Arg (2.6 mmol · kgBW
−1 · d
−1; Arg group,
n = 5). Results from these three groups were compared with an unoperated chow-fed reference group (chow control group,
n = 5). The BW gain during PN and the proportion of lipid in the total body after 14 d of PN was greater for the TyrArg group than for the PN group (
P < 0.01). Although the differences in weight gain, body water, lipid, and protein between the TyrArg and Arg groups were not significant, the mean weight gain throughout PN was greater in the TyrArg group than in the Arg group. The proportion of protein in the small intestine, colon, and gastrocnemius muscle was greater in the TyrArg and Arg groups than in the PN group (
P < 0.01). A distinct requirement for tyrosine has not been demonstrated in this model, and additional studies in stressed animals are required. In contrast, arginine had tissue-specific anabolic activity.
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