Effect of knife castration on leukocyte cytokine expression and indicators of stress, pain, and inflammation in Korean cattle bull calves.

OBJECTIVE: This study investigated the effects of surgical castration on behavior, physiological and inflammatory indicators, and leukocyte cytokine mRNA levels in Korean cattle bull calves. METHODS: Nineteen Korean cattle bull calves (average body weight, 254.5 kg; average age, 8.2 months) were divided into two treatment groups: control (n = 9) and castration (n = 10). Surgical castration was performed using Newberry knives and a Henderson castrating tool. Blood was obtained just before castration (0 h) and at 0.5 h, 6 h, 1 d, 3 d, 7 d, and 14 d after castration. Plasma cortisol (PC), saliva cortisol (SC), plasma substance P, and plasma haptoglobin concentrations, and the leucocyte mRNA levels of the interleukin-1-alpha (IL1A), interleukin-1-beta (IL1B), interleukin-1 receptor antagonist (IL1RN), and interleukin-6 (IL6) genes were analyzed. RESULTS: Castration decreased (p<0.01) the average daily gain and gain/feed ratio. Castration reduced the time spent eating (p<0.001) and the eating frequency (p<0.01) and increased (p<0.001) the lying frequency. Castration temporarily increased (p<0.05) circulating PC and SC concentrations at 0.5 h after castration. Castration temporarily increased (p<0.05) plasma substance P concentrations at 1 d after castration. Castration increased (p<0.05) plasma haptoglobin concentrations at 1 and 3 d after castration. Castration increased (p< 0.05) leukocyte mRNA levels of the IL1A, IL1B, IL1RN, and IL6 genes at 6 h after castration. CONCLUSION: Castration temporarily induced stress and expression of leucocyte inflammatory cytokine genes in Korean cattle bull calves.

Gut Epithelial Inositol Polyphosphate Multikinase Alleviates Experimental Colitis via Governing Tuft Cell Homeostasis.

BACKGROUND & AIMS: Inositol polyphosphate multikinase (IPMK), an essential enzyme for inositol phosphate metabolism, has been known to mediate major biological events such as growth. Recent studies have identified single-nucleotide polymorphisms in the IPMK gene associated with inflammatory bowel disease predisposition. Therefore, we aimed to investigate the functional significance of IPMK in gut epithelium. METHODS: We generated intestinal epithelial cell (IEC)-specific Ipmk knockout (IPMKΔIEC) mice, and assessed their vulnerability against dextran sulfate sodium-induced experimental colitis. Both bulk and single-cell RNA sequencing were performed to analyze IPMK-deficient colonic epithelial cells and colonic tuft cells. RESULTS: Although IPMKΔIEC mice developed normally and showed no intestinal abnormalities during homeostasis, Ipmk deletion aggravated dextran sulfate sodium-induced colitis, with higher clinical colitis scores, and increased epithelial barrier permeability. Surprisingly, Ipmk deletion led to a significant decrease in the number of tuft cells without influencing other IECs. Single-cell RNA sequencing of mouse colonic tuft cells showed 3 distinct populations of tuft cells, and further showed that a transcriptionally inactive population was expanded markedly in IPMKΔIEC mice, while neuronal-related cells were relatively decreased. CONCLUSIONS: Cholinergic output from tuft cells is known to be critical for the restoration of intestinal architecture upon damage, supporting that tuft cell-defective IPMKΔIEC mice are more prone to colitis. Thus, intestinal epithelial IPMK is a critical regulator of colonic integrity and tissue regeneration by determining tuft cell homeostasis and affecting cholinergic output.

Lomitapide, a cholesterol-lowering drug, is an anticancer agent that induces autophagic cell death via inhibiting mTOR.

Autophagy is a biological process that maintains cellular homeostasis and regulates the internal cellular environment. Hyperactivating autophagy to trigger cell death has been a suggested therapeutic strategy for cancer treatment. Mechanistic target of rapamycin (mTOR) is a crucial protein kinase that regulates autophagy; therefore, using a structure-based virtual screen analysis, we identified lomitapide, a cholesterol-lowering drug, as a potential mTOR complex 1 (mTORC1) inhibitor. Our results showed that lomitapide directly inhibits mTORC1 in vitro and induces autophagy-dependent cancer cell death by decreasing mTOR signaling, thereby inhibiting the downstream events associated with increased LC3 conversion in various cancer cells (e.g., HCT116 colorectal cancer cells) and tumor xenografts. Lomitapide also significantly suppresses the growth and viability along with elevated autophagy in patient-derived colorectal cancer organoids. Furthermore, a combination of lomitapide and immune checkpoint blocking antibodies synergistically inhibits tumor growth in murine MC38 or B16-F10 preclinical syngeneic tumor models. These results elucidate the direct, tumor-relevant immune-potentiating benefits of mTORC1 inhibition by lomitapide, which complement the current immune checkpoint blockade. This study highlights the potential repurposing of lomitapide as a new therapeutic option for cancer treatment.

Partial Substitution of Corn Grain in the Diet with Beet Pulp Reveals Increased Ruminal Acetate Proportion and Circulating Insulin Levels in Korean Cattle Steers.

We investigated the effects of the partial substitution of corn grain in the diet with beet pulp on growth performance, ruminal fermentation characteristics, microbial profiles, and blood lipogenic parameters in fattening steers. Twelve Korean cattle steers (body weight, 485 ± 19.32 kg; age, 18.0 ± 0.17 months) were equally divided into corn grain (CG) and beet pulp (BP) groups. Approximately 75% of dry matter of the requirement was offered as a concentrate portion, and the remaining 25% was offered as oat straw. Eighty percent of the concentrate portion was provided by a pelleted basal concentrate, and the remaining 20% with corn grain for the CG group, or 18% beet pulp plus 2.0% rumen-protected fat for the BP group, respectively, by top dressing. The experiment was conducted for 14 weeks, including a 2-week acclimation period. Growth rate was not affected by beet pulp feeding (p = 0.55). The molar proportions of ruminal acetate (p < 0.05) on wk 4, the relative abundances of ruminal cellulolytic bacteria, including Fibrobacter succinogenes (p = 0.01) and Ruminococcus albus (p = 0.04) on wk 12, and serum insulin concentrations (p < 0.05) on wk 12 were higher in the BP group than in the CG group, whereas the molar proportions of propionate (p < 0.05) on wks 8 and 12 and serum nonesterified fatty acids (p < 0.05) on wk 12 were lower in the BP group. Beet pulp could be used as a lipogenic energy source without affecting growth performance during the fattening period of cattle.

Deletion of IP6K1 in mice accelerates tumor growth by dysregulating the tumor-immune microenvironment.

A family of inositol hexakisphosphate kinases (IP6Ks) catalyzes the production of inositol pyrophosphate IP7 (5-diphosphoinositolpentakisphosphate) which is known to modulate various biological events such as cell growth. While targeting IP6K1 in various cancer cells has been well reported to control cancer cell motility and invasiveness, the role of host IP6K1 in tumor progression remains unknown. By using a syngeneic MC38 murine mouse colon carcinoma model, here we examined how host IP6K1 in the tumor microenvironment influences tumor growth. In IP6K1 knockout (KO) mice, the growth of MC38 tumor cells was markedly accelerated and host survival was significantly shortened compared with wild-type (WT). Our flow cytometric analysis revealed that tumors grown in IP6K1 KO mice had lower immune suppressive myeloid cells and M1 polarized macrophages. Notably, infiltration of both antigen-presenting dendritic cells and CD8+ cytotoxic T lymphocytes into the tumor tissues was remarkably abrogated in IP6K1 KO condition. These studies suggest that enhanced tumor growth in IP6K1 KO mice resulted from reduced anti-tumor immunity due to disturbed immune cell actions in the tumor microenvironment. In conclusion, we demonstrate that host IP6K1 acts as a tumor suppressor, most likely by fine-tuning diverse tumor-immune cell interactions, which might have implications for improving the host response against cancer progression.

Inositol Polyphosphate Multikinase Signaling: Multifaceted Functions in Health and Disease.

Inositol phosphates are water-soluble intracellular signaling molecules found in eukaryotes from yeasts to mammals, which are synthesized by a complex network of enzymes including inositol phosphate kinases. Among these, inositol polyphosphate multikinase (IPMK) is a promiscuous enzyme with broad substrate specificity, which phosphorylates multiple inositol phosphates, as well as phosphatidylinositol 4,5-bisphosphate. In addition to its catalytic actions, IPMK is known to non-catalytically control major signaling events via direct protein-protein interactions. In this review, we describe the general characteristics of IPMK, highlight its pleiotropic roles in various physiological and pathological conditions, and discuss future challenges in the field of IPMK signaling pathways.

Relationships among carcass traits, auction price, and image analysis traits of marbling characteristics in Korean cattle beef.

Marbling score (MS) is related to beef auction price (AP) in Korea, but how these relate to marbling texture (i.e. number and distribution of marbling particles [MPs]) is not known. We examined relationships among carcass traits, carcass AP, and image analysis marbling texture traits. In experiment 1, carcass data and longissimus thoracis (LT) were obtained from Korean cattle steers reared under similar feeding conditions. MS, quality grade (QG), and AP were related (P < 0.001) to numbers of coarse MPs and fine MPs and fineness index. In experiment 2, LT images photographed at a slaughterhouse were used in regression analysis within individual QG classes (QGs: 1 [middle], 1+, and 1++ [best]). AP was related (P < 0.001) to numbers of coarse MPs and fine MPs and fineness index in both QGs 1+ and 1++ but not in QG 1. Overall, several marbling texture traits were related to AP, but both MS and QG were more strongly related to AP.

Effects of dietary glycerol inclusion on growth performance, carcass and meat quality characteristics, glycogen content, and meat volatile compounds in Korean cattle steers.

OBJECTIVE: We have tested our hypothesis that inclusion of purified glycerol as a replacer of portions of dried distillers grain with solubles (DDGS) would affect growth performance, rumen fermentation and blood parameters, carcass and sensory traits, reducing sugar and glycogen contents, and volatile compound profiles in longissimus thoracis (LT) in Korean cattle steers. METHODS: A total of 20 Korean cattle steers (27.0±0.2 months old; 647±10.5 kg body weight [BW]) were assigned to a conventional control group or a glycerol group (3.17% purified glycerol addition as a replacement for DDGS and molasses). The steers were individually allowed to receive the experimental concentrate at the daily amount of 1.5% of their individual BW and a total 1.0 of kg/d of rice straw twice daily. The feeding trial was conducted for a period of 20 weeks. RESULTS: Glycerol supplementation (GS) increased (p = 0.001) concentrate intake. However, GS did not affect (p>0.05) average daily gain, feed efficiency, and ruminal volatile fatty acid concentrations. GS tended to increase (p≤0.10) serum glucose concentrations at the 16th and 20th weeks. GS decreased (p = 0.001) LT pH. GS did not affect (p>0.05) carcass traits and the chemical or physicochemical compositions, reducing sugar or glycogen contents, sensory traits, and most of volatile compounds in the LT. CONCLUSION: The inclusion of purified glycerol as a replacement for DDGS in the finishing diet did not affect growth performance, rumen fermentation parameters, and carcass quality in Korean cattle. The purified glycerol could be used as a substitute for other energy sources such as DDGS in beef cattle, depending on the price.

Testosterone deficiency caused by castration increases adiposity in male rats in a tissue-specific and diet-dependent manner.

BACKGROUND: Testosterone deficiency in men is clinically associated with the development of metabolic syndrome, which manifests as obesity, hepatic steatosis, and type-2 diabetes. We investigated the effects of castration-induced testosterone deficiency on body adiposity and the expression of genes related to lipid metabolism and glucose uptake and androgen signaling in male rats fed a normal diet (ND) or a high-fat diet (HFD). METHODS: Changes in lipid and glucose metabolism and androgen signaling were investigated at physiological and molecular levels in the muscle, liver, and adipose tissues of non-castrated and castrated rats under ND or HFD feeding. RESULTS: Castration-induced testosterone deficiency predisposed animals on ND to early development of fatty liver by activating fatty acid (FA) synthesis, whereas HFD activated hepatic FA uptake CD36 expression, leading to the development of hepatic steatosis. In rats fed ND, castration induced muscle fat accumulation by activating CD36 expression. In the subcutaneous fat of ND-fed rats, castration increased adiposity and the expression of FA synthesis-related genes, but it decreased glucose transporter gene expression. In the abdominal fat of rats fed ND, castration increased adiposity by upregulating FA synthesis-related genes, and HFD promoted adiposity by inducing FA uptake, glucose transporter, and FA synthesis-related gene expression. In rats fed ND, castration decreased body growth and muscle weight and downregulated the expression of genes androgen signaling in the longissimus dorsi muscle. CONCLUSIONS: Testosterone deficiency increases adiposity in a tissue-specific and diet-dependent manner. Testosterone deficiency decreases body and muscle weights and downregulates androgen signaling.

Transcriptome changes associated with fat deposition in the longissimus thoracis of Korean cattle following castration.

The castration of bulls increases the intramuscular fat (IMF) content in skeletal muscle. However, the biological processes of IMF accumulation in skeletal muscle after castration are not completely understood at the molecular level. This study examined the global transcriptomic changes in the longissimus thoracis muscle (LT) of bulls following castration using RNA sequencing (RNA-Seq) and identified new genes or pathways associated with beef quality. Ten bulls and 10 steers castrated at 6 months of age were slaughtered at 26 and 32 months of age respectively. For transcriptome analysis, six LT samples from three bulls and three steers were selected based on age, carcass weight, carcass quantity and beef quality grades. Using RNA-Seq, transcriptomic profiles of the LT were compared between bulls and steers. In all, 640 of the 18,027 genes identified through RNA-Seq were differentially expressed genes (DEGs) between bulls and steers. Pathway analysis of these 640 DEGs showed significant (p < .05) changes in seven Kyoto Encyclopedia of Genes and Genomes pathways, and the most significant terms were complement and coagulation cascade pathways. The transcriptomic expression patterns of 10 genes in the complement and coagulation cascades were validated using all animals through quantitative real-time polymerase chain reaction analysis. In conclusion, transcriptome changes associated with the complement and coagulation cascade pathways provide novel insights into understanding molecular mechanisms responsible for IMF accumulation following castration in beef cattle.

Inositol hexakisphosphate kinase-1 is a key mediator of prepulse inhibition and short-term fear memory.

Inositol phosphate metabolism has emerged as one of the key players in synaptic transmission. Previous studies have shown that the deletion of inositol hexakisphosphate kinase 1 (IP6K1), which is responsible for inositol pyrophosphate biosynthesis, alters probability of presynaptic vesicle release and short-term facilitation of glutamatergic synapses in mouse hippocampus. However, the behavioral and cognitive functions regulated by IP6K1 remain largely elusive. In this study, IP6K1-knockout mice exhibited decreased prepulse inhibition with no defects in Y-maze and elevated plus maze tests. Interestingly, IP6K1 knockout led to impaired short-term memory formation in a contextual fear memory retrieval test with no effect on long-term memory. Further, both hippocampal long-term potentiation and long-term depression in IP6K1-knockout mice were similar to those in the wild-type control. Taken together, the findings in this study suggest the physiological roles of IP6K1 and the associated inositol pyrophosphate metabolism in regulating sensorimotor gating as well as short-term memory.

Inositol Pyrophosphate Metabolism Regulates Presynaptic Vesicle Cycling at Central Synapses.

The coordination of synaptic vesicle exocytosis and endocytosis supports neurotransmitter release from presynaptic terminals. Although inositol pyrophosphates, such as 5-diphosphoinositol pentakisphosphate (5-IP7), are versatile signaling metabolites in many biological events, physiological actions of 5-IP7 on synaptic membrane vesicle trafficking remain unclear. Here, we investigated the role of 5-IP7 in synaptic transmission in hippocampal brain slices from inositol hexakisphosphate kinase 1 (Ip6k1)-knockout mice. We found that presynaptic release probability was significantly increased in Ip6k1-knockout neurons, implying enhanced activity-dependent synaptic vesicle exocytosis. Expression of wild-type but not catalytically inactive IP6K1 in the Ip6k1-knockout hippocampus restored the altered presynaptic release probability. Moreover, Ip6k1-knockout neurons were insensitive to folimycin, a vacuolar ATPase inhibitor, and dynasore, a dynamin inhibitor, suggesting marked impairment in synaptic endocytosis during exocytosis. Our findings collectively establish that IP6K1 and its product, 5-IP7, act as key physiological determinants for inhibition of presynaptic vesicle exocytosis and stimulation of endocytosis at central synapses.

Identification of the Antidepressant Vilazodone as an Inhibitor of Inositol Polyphosphate Multikinase by Structure-Based Drug Repositioning.

Inositol polyphosphate multikinase (IPMK) is required for the biosynthesis of inositol phosphates (IPs) through the phosphorylation of multiple IP metabolites such as IP3 and IP4. The biological significance of IPMK's catalytic actions to regulate cellular signaling events such as growth and metabolism has been studied extensively. However, pharmacological reagents that inhibit IPMK have not yet been identified. We employed a structure-based virtual screening of publicly available U.S. Food and Drug Administration-approved drugs and chemicals that identified the antidepressant, vilazodone, as an IPMK inhibitor. Docking simulations and pharmacophore analyses showed that vilazodone has a higher affinity for the ATP-binding catalytic region of IPMK than ATP and we validated that vilazodone inhibits IPMK's IP kinase activities in vitro . The incubation of vilazodone with NIH3T3-L1 fibroblasts reduced cellular levels of IP5 and other highly phosphorylated IPs without influencing IP4 levels. We further found decreased Akt phosphorylation in vilazodone-treated HCT116 cancer cells. These data clearly indicate selective cellular actions of vilazodone against IPMK-dependent catalytic steps in IP metabolism and Akt activation. Collectively, our data demonstrate vilazodone as a method to inhibit cellular IPMK, providing a valuable pharmacological agent to study and target the biological and pathological processes governed by IPMK.

Inositol polyphosphate multikinase deficiency leads to aberrant induction of synaptotagmin-2 in the forebrain.

Inositol polyphosphate multikinase (IPMK), the key enzyme responsible for the synthesis of higher inositol polyphosphates and phosphatidylinositol 3, 4, 5-trisphosphate, is known to mediate various biological events, such as cellular growth and metabolism. Conditional deletion of IPMK in excitatory neurons of the mouse postnatal forebrain results in enhanced extinction of fear memory accompanied by activation of p85 S6 kinase 1 signaling in the amygdala; it also facilitates hippocampal long-term potentiation. However, the molecular changes triggered by IPMK deletion in the brain have not been fully elucidated. In the present study, we investigated gene expression changes in the hippocampal region of IPMK conditional knockout (cKO) mice by performing genome-wide transcriptome analyses. Here we show that expression of synaptotagmin 2 (Syt2), a synaptic vesicle protein essential for Ca2+-dependent neurotransmitter release, is robustly upregulated in the forebrain of IPMKcKO mice. Compared to wild-type mice, in which weak Syt2 expression was detected in the forebrain, IPMKcKO mice showed marked increases in both Syt2 mRNA and protein expression in the hippocampus as well as the amygdala. Collectively, our results suggest a physiological role for IPMK in regulating expression of Syt2, providing a potential underlying molecular mechanism to explain IPMK-mediated neural functions.

Effects of heat stress and rumen-protected fat supplementation on growth performance, rumen characteristics, and blood parameters in growing Korean cattle steers.

OBJECTIVE: This study was performed to evaluate whether hot temperature and rumen-protected fat (RPF) supplementation affect growth performance, rumen characteristics, and serum metabolites in growing stage of Korean cattle steers. METHODS: Twenty Korean cattle steers (230.4±4.09 kg of body weight [BW], 10.7±0.09 months of age) were divided into a conventional control diet group (n = 10) and a 0.8% RPF supplementation group (n = 10). Steers were fed 1.5% BW of a concentrate diet and 4 kg of tall fescue hay for 16 weeks (July 10 to August 6 [P1], August 7 to September 3 [P2], September 4 to October 1 [P3], October 2 to 30 [P4], of 2015). RESULTS: The mean temperature-humidity index (THI) was higher (p<0.001) in P1 (76.8), P2 (76.3), and P3 (75.9) than in P4 (50.9). The mean THI of P1-3 were within the alert heat stress (HS) category range according to previously reported categories for feedlot cattle, and the mean THI of P4 was under the thermo-neutral range. Neither month nor RPF supplementation affected (p>0.05) average daily gain and gain to feed ratio. Month and RPF supplementation affected concentrations of glucose, albumin, and high-density lipoprotein (HDL); those of albumin and glucose tended to decrease (p<0.10), but HDL concentration increased (p<0.01) by RPF supplementation. Neither month nor RPF affected (p>0.05) ruminal pH, NH3-N, and volatile fatty acid concentrations, whereas the C2:C3 ratio was affected (p<0.05) by month. CONCLUSION: Korean cattle may not have been significantly affected by alert HS during the growing stage. Growth performance was higher during hotter months, although some changes in blood metabolites were observed. The RPF supplementation affected some blood lipids and carbohydrate metabolites but did not affect growth performance.

Inositol polyphosphate multikinase mediates extinction of fear memory.

Inositol polyphosphate multikinase (IPMK), the key enzyme for the biosynthesis of higher inositol polyphosphates and phosphatidylinositol 3,4,5-trisphosphate, also acts as a versatile signaling player in regulating tissue growth and metabolism. To elucidate neurobehavioral functions of IPMK, we generated mice in which IPMK was deleted from the excitatory neurons of the postnatal forebrain. These mice showed no deficits in either novel object recognition or spatial memory. IPMK conditional knockout mice formed cued fear memory normally but displayed enhanced fear extinction. Signaling analyses revealed dysregulated expression of neural genes accompanied by selective activation of the mechanistic target of rapamycin (mTOR) regulatory enzyme p85 S6 kinase 1 (S6K1) in the amygdala following fear extinction. The IPMK mutants also manifested facilitated hippocampal long-term potentiation. These findings establish a signaling action of IPMK that mediates fear extinction.

Effects of ambient temperature and rumen-protected fat supplementation on growth performance, rumen fermentation and blood parameters during cold season in Korean cattle steers.

OBJECTIVE: This study was performed to evaluate whether cold ambient temperature and dietary rumen-protected fat (RPF) supplementation affect growth performance, rumen fermentation, and blood parameters in Korean cattle steers. METHODS: Twenty Korean cattle steers (body weight [BW], 550.6±9.14 kg; age, 19.7±0.13 months) were divided into a conventional control diet group (n = 10) and a 0.5% RPF supplementation group (n = 10). Steers were fed a concentrate diet (1.6% BW) and a rice straw diet (1 kg/d) for 16 weeks (January 9 to February 5 [P1], February 6 to March 5 [P2], March 6 to April 3 [P3], and April 4 to May 2 [P4]). RESULTS: The mean and minimum indoor ambient temperatures in P1 (-3.44°C, -9.40°C) were lower (p<0.001) than those in P3 (5.87°C, -1.86°C) and P4 (11.18°C, 4.28°C). The minimum temperature in P1 fell within the moderate cold-stress (CS) category, as previously reported for dairy cattle, and the minimum temperatures of P2 and P3 were within the mild CS category. Neither month nor RPF supplementation affected the average daily gain or gain-to-feed ratio (p>0.05). Ruminal ammonia nitrogen concentrations were higher (p<0.05) in cold winter than spring. Plasma cortisol concentrations were lower (p<0.05) in the coldest month than in the other months. Serum glucose concentrations were generally higher in colder months than in the other months but were unaffected by RPF supplementation. RPF supplementation increased both total cholesterol (p = 0.004) and high-density lipoprotein (HDL) concentrations (p = 0.03). CONCLUSION: Korean cattle may not be significantly affected by moderate CS, considering that the growth performance of cattle remained unchanged, although variations in blood parameters were observed among the studied months. RPF supplementation altered cholesterol and HDL concentrations but did not affect growth performance.

Genetic, management, and nutritional factors affecting intramuscular fat deposition in beef cattle - A review.

Intramuscular fat (IMF) content in skeletal muscle including the longissimus dorsi muscle (LM), also known as marbling fat, is one of the most important factors determining beef quality in several countries including Korea, Japan, Australia, and the United States. Genetics and breed, management, and nutrition affect IMF deposition. Japanese Black cattle breed has the highest IMF content in the world, and Korean cattle (also called Hanwoo) the second highest. Here, we review results of research on genetic factors (breed and sex differences and heritability) that affect IMF deposition. Cattle management factors are also important for IMF deposition. Castration of bulls increases IMF deposition in most cattle breeds. The effects of several management factors, including weaning age, castration, slaughter weight and age, and environmental conditions on IMF deposition are also reviewed. Nutritional factors, including fat metabolism, digestion and absorption of feed, glucose/starch availability, and vitamin A, D, and C levels are important for IMF deposition. Manipulating IMF deposition through developmental programming via metabolic imprinting is a recently proposed nutritional method to change potential IMF deposition during the fetal and neonatal periods in rodents and domestic animals. Application of fetal nutritional programming to increase IMF deposition of progeny in later life is reviewed. The coordination of several factors affects IMF deposition. Thus, a combination of several strategies may be needed to manipulate IMF deposition, depending on the consumer's beef preference. In particular, stage-specific feeding programs with concentrate-based diets developed by Japan and Korea are described in this article.

Differential expression of extracellular matrix and integrin genes in the longissimus thoracis between bulls and steers and their association with intramuscular fat contents.

This study was performed to compare expression of genes for extracellular matrix (ECM) components, ECM degrading factors, and integrin subunits in the longissimus thoracis (LT) between bulls and steers. Steers had lower (P<0.05) ECM component collagen type 1 α1 and collagen type 3 α1 mRNA levels than did bulls, but they had higher (P<0.05) thrombospondin 1 mRNA and protein levels. Steers had higher (P<0.01) matrix metalloproteinase (MMP) 9 mRNA levels than did bulls. Steers had higher (P<0.05) integrin α5 mRNA levels but lower (P<0.05) integrin ß6 mRNA and protein levels; however, expression levels of several other integrin subunits were not different between steers and bulls. MMP9 mRNA levels were positively correlated (P<0.05) with intramuscular fat content in bull group. In conclusion, these results demonstrate that castration has moderate effects on expression of ECM components, ECM degrading factors, and integrin subunit genes in the LT.

Inositol polyphosphate multikinase promotes Toll-like receptor-induced inflammation by stabilizing TRAF6.

Toll-like receptor (TLR) signaling is tightly controlled to protect hosts from microorganisms while simultaneously preventing uncontrolled immune responses. Tumor necrosis factor receptor-associated factor 6 (TRAF6) is a critical mediator of TLR signaling, but the precise mechanism of how TRAF6 protein stability is strictly controlled still remains obscure. We show that myeloid-specific deletion of inositol polyphosphate multikinase (IPMK), which has both inositol polyphosphate kinase activities and noncatalytic signaling functions, protects mice against polymicrobial sepsis and lipopolysaccharide-induced systemic inflammation. IPMK depletion in macrophages results in decreased levels of TRAF6 protein, thereby dampening TLR-induced signaling and proinflammatory cytokine production. Mechanistically, the regulatory role of IPMK is independent of its catalytic function, instead reflecting its direct binding to TRAF6. This interaction stabilizes TRAF6 by blocking its K48-linked ubiquitination and subsequent degradation by the proteasome. Thus, these findings identify IPMK as a key determinant of TRAF6 stability and elucidate the physiological function of IPMK in TLR-induced innate immunity.