Belantamab Mafodotin, Pomalidomide, and Dexamethasone in Multiple Myeloma.

BACKGROUND: Triplet or quadruplet therapies incorporating proteasome inhibitors, immunomodulators, and anti-CD38 antibodies have led to prolonged survival among patients with newly diagnosed multiple myeloma; however, most patients have a relapse. Frontline lenalidomide therapy has increased the number of patients with lenalidomide-refractory disease at the time of the first relapse. METHODS: In this phase 3, randomized, open-label trial, we evaluated belantamab mafodotin, pomalidomide, and dexamethasone (BPd), as compared with pomalidomide, bortezomib, and dexamethasone (PVd), in lenalidomide-exposed patients who had relapsed or refractory myeloma after at least one line of therapy. The primary end point was progression-free survival. Disease response and safety were also assessed. RESULTS: A total of 302 patients underwent randomization; 155 were assigned to the BPd group, and 147 to the PVd group. At a median follow-up of 21.8 months (range, <0.1 to 39.2), the 12-month estimated progression-free survival with BPd was 71% (95% confidence interval [CI], 63 to 78), as compared with 51% (95% CI, 42 to 60) with PVd (hazard ratio for disease progression or death, 0.52; 95% CI, 0.37 to 0.73; P<0.001). Data on overall survival were immature. The percentage of patients with a response to treatment (partial response or better) was 77% (95% CI, 70 to 84) in the BPd group and 72% (95% CI, 64 to 79) in the PVd group; 40% (95% CI, 32 to 48) and 16% (95% CI, 11 to 23), respectively, had a complete response or better. Grade 3 or higher adverse events occurred in 94% of the patients in the BPd group and 76% of those in the PVd group. Ocular events occurred in 89% of the patients who received BPd (grade 3 or 4 in 43%) and 30% of those who received PVd (grade 3 or 4 in 2%); ocular events in the BPd group were managed with belantamab mafodotin dose modification. Ocular events led to treatment discontinuation in 9% of the patients in the BPd group and in no patients in the PVd group. CONCLUSIONS: Among lenalidomide-exposed patients with relapsed or refractory myeloma, BPd conferred a significantly greater benefit than PVd with respect to progression-free survival, as well as deeper, more durable responses. Ocular events were common but were controllable by belantamab mafodotin dose modification. (Funded by GSK; DREAMM-8 ClinicalTrials.gov number, NCT04484623; EudraCT number, 2018-00434-21.).

Discovery of a Conditionally Activated IL-2 that Promotes Antitumor Immunity and Induces Tumor Regression.

IL-2 is a cytokine clinically approved for the treatment of melanoma and renal cell carcinoma. Unfortunately, its clinical utility is hindered by serious side effects driven by the systemic activity of the cytokine. Here, we describe the design and characterization of a conditionally activated IL-2 prodrug, WTX-124, that takes advantage of the dysregulated protease milieu of tumors. WTX-124 was engineered as a single molecule containing an inactivation domain and a half-life extension domain that are tethered to a fully active IL-2 by protease-cleavable linkers. We show that the inactivation domain prevented IL-2 from binding to its receptors in nontumor tissues, thereby minimizing the toxicity associated with systemic exposure to IL-2. The half-life extension element improves the pharmacokinetic profile of WTX-124 over free IL-2, allowing for greater exposure. WTX-124 was preferentially activated in tumor tissue by tumor-associated proteases, releasing active IL-2 in the tumor microenvironment. In vitro assays confirmed that the activity of WTX-124 was dependent on proteolytic activation, and in vivo WTX-124 treatment resulted in complete rejection of established tumors in a cleavage-dependent manner. Mechanistically, WTX-124 treatment triggered the activation of T cells and natural killer (NK) cells, and markedly shifted the immune activation profile of the tumor microenvironment, resulting in significant inhibition of tumor growth in syngeneic tumor models. Collectively, these data demonstrate that WTX-124 minimizes the toxicity of IL-2 treatment in the periphery while retaining the full pharmacology of IL-2 in the tumor microenvironment, supporting its further development as a cancer immunotherapy treatment. See related Spotlight by Silva, p. 544.

Measuring glucose at the site of insulin delivery with a redox-mediated sensor.

Automated insulin delivery systems for people with type 1 diabetes rely on an accurate subcutaneous glucose sensor and an infusion cannula that delivers insulin in response to measured glucose. Integrating the sensor with the infusion cannula would provide substantial benefit by reducing the number of devices inserted into subcutaneous tissue. We describe the sensor chemistry and a calibration algorithm to minimize impact of insulin delivery artifacts in a new glucose sensing cannula. Seven people with type 1 diabetes undergoing automated insulin delivery used two sensing cannulae whereby one delivered a rapidly-acting insulin analog and the other delivered a control phosphate buffered saline (PBS) solution with no insulin. While there was a small artifact in both conditions that increased for larger volumes, there was no difference between the artifacts in the sensing cannula delivering insulin compared with the sensing cannula delivering PBS as determined by integrating the area-under-the-curve of the sensor values following delivery of larger amounts of fluid (P = 0.7). The time for the sensor to recover from the artifact was found to be longer for larger fluid amounts compared with smaller fluid amounts (10.3 ± 8.5 min vs. 41.2 ± 78.3 s, P < 0.05). Using a smart-sampling Kalman filtering smoothing algorithm improved sensor accuracy. When using an all-point calibration on all sensors, the smart-sampling Kalman filter reduced the mean absolute relative difference from 10.9% to 9.5% and resulted in 96.7% of the data points falling within the A and B regions of the Clarke error grid. Despite a small artifact, which is likely due to dilution by fluid delivery, it is possible to continuously measure glucose in a cannula that simultaneously delivers insulin.

An Amperometric Glucose Sensor Integrated into an Insulin Delivery Cannula: In Vitro and In Vivo Evaluation.

BACKGROUND: Labeling prohibits delivery of insulin at the site of subcutaneous continuous glucose monitoring (CGM). Integration of the sensing and insulin delivery functions into a single device would likely increase the usage of CGM in persons with type 1 diabetes. METHODS: To understand the nature of such interference, we measured glucose at the site of bolus insulin delivery in swine using a flexible electrode strip that was laminated to the outer wall of an insulin delivery cannula. In terms of sensing design, we compared H2O2-measuring sensors biased at 600 mV with redox mediator-type sensors biased at 175 mV. RESULTS: In H2O2-measuring sensors, but not in sensors with redox-mediated chemistry, a spurious rise in current was seen after insulin lis-pro boluses. This prolonged artifact was accompanied by electrode poisoning. In redox-mediated sensors, the patterns of sensor signals acquired during delivery of saline and without any liquid delivery were similar to those acquired during insulin delivery. CONCLUSION: Considering in vitro and in vivo findings together, it became clear that the mechanism of interference is the oxidation, at high bias potentials, of phenolic preservatives present in insulin formulations. This effect can be avoided by the use of redox mediator chemistry using a low bias potential.

Suppression of IFNgamma+mycobacterial lipoarabinomannan-induced NO by IL-4 is due to decreased IRF-1 expression.

In mice, and possibly in humans, nitric oxide (NO) is an important host-defense molecule against Mycobacterium tuberculosis. Inducible nitric oxide synthase (iNOS) and NO are upregulated in murine macrophages stimulated with interferon-gamma (IFNgamma) and mannose-capped lipoarabinomannan (ManLAM), a major lipoglycan in the cell wall of M. tuberculosis. Interleukin-4 (IL-4) can inhibit NO expression and may impair host immune response to M. tuberculosis. Therefore, we sought to determine the mechanism by which IL-4 inhibits IFNgamma+ManLAM-induced NO production. Since l-arginine is the substrate for both iNOS and arginase, and IL-4 increases arginase activity by inducing its production, a plausible mechanism of IL-4 inhibition of NO expression is via depletion of l-arginine through increased arginase activity. Herein, we show that IL-4 inhibited iNOS gene expression at the transcriptional level, suggesting an inhibitory mechanism that is independent of the competition for l-arginine between iNOS and arginase. Furthermore, pharmacologic inhibition of IL-4-induced arginase activity did not abrogate IL-4 inhibition of IFNgamma+ManLAM-induced NO expression. Instead, inhibition by IL-4 was mediated principally by the ability of IL-4 to inhibit the production of IFNgamma-induced interferon-gamma response factor-1 (IRF-1) protein, a critically important transcriptional element that enhances expression of IFNgamma-inducible genes such as iNOS.

Role of calcitriol and cortisol on human adipocyte proliferation and oxidative and inflammatory stress: a microarray study.

Dietary calcium inhibits adiposity, and a key underlying mechanism is suppression of calcitriol, which modulates Ca(2+) signaling and mitochondrial uncoupling in adipocytes. We demonstrated that calcitriol directly regulates adipocyte 11beta-HSD-1 expression and cortisol production in human adipocytes in vitro and dietary calcium inhibits visceral adipose tissue 11beta-HSD-1 expression in mice, indicating an interaction of calcitriol and cortisol in obesity. Consequently, we have evaluated the gene expression profile of human subcutaneous adipocytes treated with calcitriol and/or cortisone. Data analysis demonstrated significant calcitriol modulation of gene expression toward inhibition of the adipocyte apoptosis (e.g., VEGF and STC-2) and promotion of adipocyte proliferation (e.g., IGF-1 and IGF-1R). Calcitriol also up-regulated oxidative stress and inflammatory genes such as NOX-4 and TLR-3. The calcitriol/cortisone combination resulted in significant additional up-regulation of 11beta-HSD-1 and down-regulation of adiponectin expression, while cortisone exerted little independent effect in the absence of calcitriol. Overall, calcitriol stimulated a pattern of adipocyte gene expression which favored adipocyte proliferation, oxidative and inflammatory stress and visceral adiposity, and these effects were amplified in the presence of cortisone; however, this conclusion must be tempered by the adipocyte source (subcutaneous) and requires confirmation in visceral adipocytes.

Adenovirus serotype 5 E1A sensitizes tumor cells to NKG2D-dependent NK cell lysis and tumor rejection.

The expression of the Adenovirus serotype 5 (Ad5) E1A oncogene sensitizes tumor cells to natural killer (NK) cell-mediated killing and tumor rejection in vivo. These effects are dependent on the ability of E1A to bind the transcriptional coadaptor protein p300. To test the hypothesis that E1A up-regulates ligands recognized by the NKG2D-activating receptor, we stably transfected the highly tumorigenic mouse fibrosarcoma cell line MCA-205 with Ad5-E1A or a mutant form of E1A that does not interact with p300 (E1A-Deltap300). Ad5-E1A, but not E1A-Deltap300, up-regulated the expression of the NKG2D ligand retinoic acid early inducible (RAE)-1, but not murine ULBP-like transcript 1, another NKG2D ligand, in four independently derived MCA-205 transfectants. The up-regulation of RAE-1 by E1A targeted MCA-205 tumor cells to lysis by NK cells, resulting in NKG2D-dependent tumor rejection in vivo. Moreover, the up-regulation of NKG2D ligands by E1A was not limited to mouse tumor cells, as E1A also increased the expression of NKG2D ligands on primary baby mouse kidney cells, human MB435S breast cancer cells, and human H4 fibrosarcoma cells.

Effect of energy-reduced diets high in dairy products and fiber on weight loss in obese adults.

OBJECTIVE: Studies suggest that high-dairy and high-fiber/low-glycemic index diets may facilitate weight loss, but data are conflicting. The effects on weight loss and body fat of a high-dairy diet and a diet high in dairy and fiber and low in glycemic index were compared with a standard diet. RESEARCH METHODS AND PROCEDURES: Ninety obese subjects were recruited into a randomized trial of three diets designed to provide a calorie deficit of 500 calories/d over a 48-week period. The study compared a moderate (not low)-calcium diet with a high-calcium diet. RESULTS: Seventy-two subjects completed the study. Significant weight and fat loss occurred with all three diets. A diet with 1400 mg of calcium did not result in greater weight (11.8 +/- 6.1 kg) or fat (9.0 +/- 6.0 kg) loss than a diet with 800 mg of calcium (10.0 +/- 6.8 and 7.5 +/- 6.6 kg, respectively). A diet with 1400 mg of calcium, increased fiber content, and fewer high-glycemic index foods did not result in greater weight (10.6 +/- 6.8 kg) or fat (8.5 +/- 7.8 kg) loss than the standard diet with 800 mg of calcium. Lipid profile, high-sensitivity C-reactive protein, leptin, fasting glucose, and insulin improved significantly, but there were no significant differences between the experimental diets and the control diet. DISCUSSION: We found no evidence that diets higher than 800 mg of calcium in dairy products or higher in fiber and lower in glycemic index enhance weight reduction beyond what is seen with calorie restriction alone.

1,25-dihydroxyvitamin D3 modulation of adipocyte glucocorticoid function.

OBJECTIVE: 1,25-Dihydroxyvitamin D3 dose dependently increases intracellular calcium in human adipocytes. We have demonstrated that suppression of circulating 1,25-dihydroxyvitamin D3 levels by increasing dietary calcium reduces adipocyte intracellular calcium and reduces adiposity in both humans and rodents, with preferential loss of trunk fat. Autocrine production of cortisol by adipocytes of mice overexpressing 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD 1) in adipose tissue increases visceral adiposity, whereas knockout of 11beta-HSD 1 appears to attenuate truncal obesity. Accordingly, our objective was to investigate the role of 1,25-dihydroxyvitamin D3 in the modulation of adipocyte glucocorticoid metabolism. RESEARCH METHODS AND PROCEDURES: We examined the effect of 1,25-dihydroxyvitamin D3 or angiotensin II on cortisol production and expression using real-time reverse transcriptase-polymerase chain reaction of 11beta-HSD 1, angiotensin II receptor type 1 (AT1), and AT2 receptor in human adipocytes. RESULTS: Adipocytes produced negligible cortisol in the absence of substrate (cortisone). In the presence of cortisone (1 to 10 nM), there was significant cortisol production, which was dose dependently augmented (2- to 6-fold, p < 0.001) by 1,25-dihydroxyvitamin D3 (0.1 to 10 nM). 1,25-Dihydroxyvitamin D3 dose dependently increased 11beta-HSD 1 expression up to 2-fold (p < 0.01) in both the presence and absence of cortisone. In contrast, 1,25-dihydroxyvitamin D3 dose dependently decreased adipocyte AT1 expression (by 30% to 50%, p < 0.001) in both the presence and absence of cortisone, suggesting compensatory down-regulation of AT(1). DISCUSSION: We conclude that 1,25-dihydroxyvitamin D3 directly regulates adipocyte 11beta-HSD 1 expression and, consequently, local cortisol levels and that this may contribute to the preferential loss of visceral adiposity by high-calcium diets.

Effect of dietary carbohydrate source on the development of obesity in agouti transgenic mice.

OBJECTIVES: Our objective was to evaluate the effects of a qualitative change in dietary carbohydrate source on body weight and adiposity in a rodent model of diet-induced obesity. RESEARCH METHODS AND PROCEDURES: We evaluated the effects of high-fat diets (basal) varying in carbohydrate source in aP2-agouti transgenic mice. In the ad libitum study, animals were given free access to the basal diet or one of four test diets for 6 weeks. In two of the diets, dietary carbohydrate was derived from a single source: mung bean noodles (MUNG) or rolled oats (ROLL). The remaining diets were designed to mimic commercially available instant oatmeal with added sugar (IO-S) or flavored instant oatmeal (IO-F). In the energy-restricted study, animals were given ad libitum access to the basal diet for 6 weeks. Subsequently, animals were assigned to one of six treatment groups for 6 weeks. One group was continued on the basal diet ad libitum. The remaining groups were maintained with energy restriction (70% ad libitum) on either the basal, MUNG, ROLL, IO-S, or IO-F diet. RESULTS: Subcutaneous fat pad mass was significantly higher (p<0.05) in the energy-restricted basal and IO-S groups compared with the energy-restricted ROLL diet. Similarly, visceral fat pad mass was significantly lower with ROLL and MUNG diets (p<0.05 for both) compared with basal and IO-S diets, and the insulin:glucose ratio was reduced (by 23% to 34%, p<0.05) in these two diets compared with all others. In ad libitum-fed animals, liver fatty acid synthase expression was 43% to 62% lower (p<0.05) with ROLL and MUNG diets compared with all others. DISCUSSION: These data suggest that a qualitative change in dietary carbohydrate source modulates body weight and adiposity.

Macrophages kill human papillomavirus type 16 E6-expressing tumor cells by tumor necrosis factor alpha- and nitric oxide-dependent mechanisms.

The expression of adenovirus serotype 2 or 5 (Ad2/5) E1A sensitizes cells to killing by NK cells and activated macrophages, a property that correlates with the ability of E1A to bind the transcriptional coadaptor proteins p300-CBP. The E6 oncoproteins derived from the high-risk human papillomaviruses (HPV) interact with p300 and can complement mutant forms of E1A that cannot interact with p300 to induce cellular immortalization. Therefore, we determined if HPV type 16 (HPV16) E6 could sensitize cells to killing by macrophages and NK cells. HPV16 E6 expression sensitized human (H4 and C33A) and murine (MCA-102) cell lines to lysis by macrophages but not by NK cells. The lysis of cells that expressed E6 by macrophages was p53 independent but dependent on the production of tumor necrosis factor alpha (TNF-alpha) or nitric oxide (NO) by macrophages. Unlike cytolysis assays with macrophages, E6 expression did not significantly sensitize cells to lysis by the direct addition of NO or TNF-alpha. Like E1A, E6 has been reported to sensitize cells to lysis by TNF-alpha by inhibiting the TNF-alpha-induced activation of NF-kappaB. We found that E1A, but not E6, blocked the TNF-alpha-induced activation of NF-kappaB, an activity that correlated with E1A-p300 binding. In summary, Ad5 E1A and HPV16 E6 sensitized cells to lysis by macrophages. Unlike E1A, E6 did not block the ability of TNF-alpha to activate NF-kappaB or sensitize cells to lysis by NK cells, TNF-alpha, or NO. Thus, there appears to be a spectrum of common and unique biological activities that result as a consequence of the interaction of E6 or E1A with p300-CBP.

Expression of an E1A/E7 chimeric protein sensitizes tumor cells to killing by activated macrophages but not NK cells.

Adenovirus (Ad) E1A and human papillomavirus (HPV) E7 express homologous conserved regions (CRs) that mediate their shared biological functions. Despite their similarities, the expression of E1A sensitizes tumor cells to killing by NK cells and macrophages but the expression of E7 does not, a factor that may contribute to the dissimilar oncogenicities of Ad and HPV. This study was undertaken to define molecular differences between E1A and E7 that are responsible for the ability of E1A and the inability of E7 to sensitize cells to killing by NK cells and macrophages. Genetic mapping studies using human fibrosarcoma cells (H4) that stably expressed mutant forms of E1A showed that only those forms of E1A that interacted with the transcriptional coadaptor protein p300 sensitized cells to killing by NK cells and macrophages. E7 lacks the N-terminal p300-binding region present in E1A. Therefore, a chimeric E1A/E7 gene was constructed that included the N terminus and the CR1 (p300-binding) domain of E1A fused to CR2 and the C-terminal sequences of E7. The E1A/E7 protein interacted with p300 and pRb and immortalized primary mouse embryo fibroblasts (MEF). The expression of E1A/E7 sensitized H4 and MEF cells to killing by activated macrophages but not to killing by NK cells. Therefore, N-terminal differences between E1A and E7 that map to the E1A-p300 binding region accounted for differences in their abilities to sensitize cells to killing by macrophages. However, regions in addition to the E1A-p300 binding region are required to sensitize cells to killing by NK cells.

Calcium and dairy acceleration of weight and fat loss during energy restriction in obese adults.

OBJECTIVE: Increasing 1,25-dihydroxyvitamin D in response to low-calcium diets stimulates adipocyte Ca2+ influx and, as a consequence, stimulates lipogenesis, suppresses lipolysis, and increases lipid accumulation, whereas increasing dietary calcium inhibits these effects and markedly accelerates fat loss in mice subjected to caloric restriction. Our objective was to determine the effects of increasing dietary calcium in the face of caloric restriction in humans. RESEARCH METHODS AND PROCEDURES: We performed a randomized, placebo-controlled trial in 32 obese adults. Patients were maintained for 24 weeks on balanced deficit diets (500 kcal/d deficit) and randomized to a standard diet (400 to 500 mg of dietary calcium/d supplemented with placebo), a high-calcium diet (standard diet supplemented with 800 mg of calcium/d), or high-dairy diet (1200 to 1300 mg of dietary calcium/d supplemented with placebo). RESULTS: Patients assigned to the standard diet lost 6.4 +/- 2.5% of their body weight, which was increased by 26% (to 8.6 +/- 1.1%) on the high-calcium diet and 70% (to 10.9 +/- 1.6% of body weight) on the high-dairy diet (p < 0.01). Fat loss was similarly augmented by the high-calcium and high-dairy diets, by 38% and 64%, respectively (p < 0.01). Moreover, fat loss from the trunk region represented 19.0 +/- 7.9% of total fat loss on the low-calcium diet, and this fraction was increased to 50.1 +/- 6.4% and 66.2 +/- 3.0% on the high-calcium and high-dairy diets, respectively (p < 0.001). DISCUSSION: Increasing dietary calcium significantly augmented weight and fat loss secondary to caloric restriction and increased the percentage of fat lost from the trunk region, whereas dairy products exerted a substantially greater effect.

Adenovirus E1A, not human papillomavirus E7, sensitizes tumor cells to lysis by macrophages through nitric oxide- and TNF-alpha-dependent mechanisms despite up-regulation of 70-kDa heat shock protein.

Expression of adenovirus (Ad) serotype 2 or 5 (Ad2/5) E1A or human papillomavirus (HPV)16 E7 reportedly sensitizes cells to lysis by macrophages. Macrophages possess several mechanisms to kill tumor cells including TNF-alpha, NO, reactive oxygen intermediates (ROI), and Fas ligand (FasL). E1A sensitizes cells to apoptosis by TNF-alpha, and macrophages kill E1A-expressing cells, in part through the elaboration of TNF-alpha. However, E1A also up-regulates the expression of 70-kDa heat shock protein, a protein that inhibits killing by TNF-alpha and NO, thereby protecting cells from lysis by macrophages. Unlike E1A, E7 does not sensitize cells to killing by TNF-alpha, and the effector mechanism(s) used by macrophages to kill E7-expressing cells remain undefined. The purpose of this study was to further define the capacity of and the effector mechanisms used by macrophages to kill tumor cells that express Ad5 E1A or HPV16 E7. We found that Ad5 E1A, but not HPV16 E7, sensitized tumor cells to lysis by macrophages. Using macrophages derived from mice unable to make TNF-alpha, NO, ROI, or FasL, we determined that macrophages used NO, and to a lesser extent TNF-alpha, but not FasL or ROI, to kill E1A-expressing cells. Through the use of S-nitroso-N-acetylpenicillamine, which releases NO upon exposure to an aqueous environment, E1A was shown to directly sensitize tumor cells to NO-induced death. E1A sensitized tumor cells to lysis by macrophages despite up-regulating the expression of 70-kDa heat shock protein. In summary, E1A, but not E7, sensitized tumor cells to lysis by macrophages. Macrophages killed E1A-expressing cells through NO- and TNF-alpha-dependent mechanisms.

Role of the NF-kappaB signaling pathway and kappaB cis-regulatory elements on the IRF-1 and iNOS promoter regions in mycobacterial lipoarabinomannan induction of nitric oxide.

Nitric oxide (NO(.)) produced by inducible nitric oxide synthase (iNOS) is an important host defense molecule against Mycobacterium tuberculosis in mononuclear phagocytes. The objective of this study was to determine the role of the IkappaBalpha kinase-nuclear factor kappaB (IKK-NF-kappaB) signaling pathway in the induction of iNOS and NO(.) by a mycobacterial cell wall lipoglycan known as mannose-capped lipoarabinomannan (ManLAM) in mouse macrophages costimulated with gamma interferon (IFN-gamma). NF-kappaB was activated by ManLAM as shown by electrophoretic mobility shift assay, by immunofluorescence of translocated NF-kappaB in intact cells, and by a reporter gene driven by four NF-kappaB-binding elements. Transduction of an IkappaBalpha mutant (Ser32/36Ala) significantly inhibited NO(.) expression induced by IFN-gamma plus ManLAM. An activated SCF complex, a heterotetramer (Skp1, Cul-1, beta-TrCP [F-box protein], and ROC1) involved with ubiquitination, is also required for iNOS-NO(.) induction. Two NF-kappaB-binding sites (kappaBI and kappaBII) present on the 5'-flanking region of the iNOS promoter bound ManLAM-induced NF-kappaB similarly. By use of reporter constructs in which one or both sites are mutated, both NF-kappaB-binding positions were essential in iNOS induction by IFN-gamma plus ManLAM. IFN-gamma-induced activation of the IRF-1 transcriptional complex is a necessary component in host defense against tuberculosis. Although the 5'-flanking region of the IRF-1 promoter contains an NF-kappaB-binding site and ManLAM-induced NF-kappaB also binds to this site, ManLAM was unable to induce IRF-1 expression. The influence of mitogen-activated protein kinases on IFN-gamma plus ManLAM induction of iNOS-NO(.) is not due to any effects on ManLAM induction of NF-kappaB.

Effects of dietary carbohydrate on the development of obesity in heterozygous Zucker rats.

Rats carrying one copy of the fa allele are predisposed to diet-induced metabolic disturbances which contribute to hyperinsulinemia, obesity and dyslipidemia. To investigate the role of dietary carbohydrate and fat in the development of these conditions, we fed 6-week old male heterozygous (fa/+) lean rats carbohydrate-free diets containing primarily saturated fat either ad libitum or pair-fed. These diets were compared to standard chow and to a high saturated fat mixed diet containing 10% energy from sucrose for 4 weeks. The carbohydrate-free diet resulted in significantly lower circulating glucose levels compared to all other groups (p = 0.006). Weight gain was negligible in the carbohydrate free groups compared to standard diet and 10% sucrose diet (p = 0.03). This was reflected in energy efficiency which was markedly reduced (90%) in the carbohydrate-free groups compared to the other groups (p = 0.04). Corresponding changes were noted in fat pad mass. The subscapular and epididymal fat pads were increased 42% and 44%, respectively, in animals consuming the 10% sucrose diet compared to all other groups (p < 0.01). Comparable changes in fatty acid synthase (FAS) mRNA were observed in response to the carbohydrate-free diet, which resulted in a 53% decrease in adipocyte FAS mRNA (p < 0.001). Addition of 10% sucrose to the diet completely reversed this effect resulting in a 69% increase in adipocyte FAS mRNA compared to the carbohydrate-free groups (p = 0.01). Similarly, hepatic FAS mRNA was elevated by 51% and 66% in the 10% sucrose and standard diet groups respectively, compared to the carbohydrate-free groups. Therefore, diets that contain minimal carbohydrate may minimize net lipid storage and adiposity.