Fisetin attenuates periodontitis through FGFR1/TLR4/NLRP3 inflammasome pathway.

The purpose of the present study was to investigate the pharmacological effect of Fisetin on experimental periodontitis in rats and explore its potential mechanism. The ligature/LPS method was used to induce periodontitis in rats. LPS was employed to cause inflammation in Human gingival fibroblasts (HGF). The transfections with FGFR1 SiRNA, NLRP3 SiRNA and the selective TLR4 inhibitor TAK242 were used to investigate the mechanism of Fisetin-mediated inflammatory reaction in LPS-induced HGF. As a result, Fisetin reduced the alveolar bone gap, reversed histopathological lesion and inhibited serum inflammatory cytokine concentration in periodontitis rats. Fisetin decreased the inflammatory cytokine contents in the supernatant of LPS-induced HGF. The inhibitory effect of Fisetin might be attributed to FGFR1/TLR4/NLRP3 inflammasome pathway both in vivo and in vitro. The suppressions of FGFR1, TLR4 and NLRP3 proved that FGFR1/TLR4/NLRP3 signaling was involved in the Fisetin-mediated inflammatory response. Fisetin also inhibited NLRP3 priming. The data demonstrated that Fisetin attenuated periodontitis by inhibiting inflammatory reaction via FGFR1/TLR4/NLRP3 inflammasome pathway.

Antibody-mediated activation of the FGFR1/Klothoß complex corrects metabolic dysfunction and alters food preference in obese humans.

Fibroblast growth factor 21 (FGF21) controls metabolic organ homeostasis and eating/drinking behavior via FGF receptor 1/Klothoß (FGFR1/KLB) complexes expressed in adipocytes, pancreatic acinar cells, and the nervous system in mice. Chronic administration of recombinant FGF21 or engineered variants improves metabolic health in rodents, nonhuman primates, and humans; however, the rapid turnover of these molecules limits therapeutic utility. Here we show that the bispecific anti-FGFR1/KLB agonist antibody BFKB8488A induced marked weight loss in obese cynomolgus monkeys while elevating serum adiponectin and the adipose expression of FGFR1 target genes, demonstrating its action as an FGF21 mimetic. In a randomized, placebo-controlled, single ascending-dose study in overweight/obese human participants, subcutaneous BFKB8488A injection caused transient body weight reduction, sustained improvement in cardiometabolic parameters, and a trend toward reduction in preference for sweet taste and carbohydrate intake. These data suggest that specific activation of the FGFR1/KLB complex in humans can be used as therapy for obesity-related metabolic defects.

PD-L1, FGFR1, PIK3CA, PTEN, and p16 expression in pulmonary emphysema and chronic obstructive pulmonary disease with resected lung squamous cell carcinoma.

BACKGROUND: Emphysema and chronic obstructive pulmonary disease (COPD) are well known independent risk factors for lung cancer. However, the developmental mechanisms between emphysema/COPD and lung cancer remain unknown. The purpose of this study was to evaluate PD-L1, FGFR1, PIK3CA, PTEN, and p16 expression in squamous cell carcinoma (SCC) associated with emphysema/COPD. METHODS: A total of 59 patients with squamous cell lung carcinoma (SCC) resected between 2008 and 2012 were retrospectively reviewed. Emphysema was assessed according to the Goddard score. Total severity was divided into none-mild (0-7), moderate (8-15), and severe (≥ 16). Local severity around the existing tumor was divided into no emphysema (0) and presence of emphysema (1-4). COPD severity was based on the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria. PD-L1, FGFR1, PIK3CA, PTEN, and p16 expression were evaluated by immunohistochemistry (IHC). Expression level was classified as tumor cells (TC) 3 (≥ 50%), TC2 (5-49%), TC1 (1-4%), or TC0 (< 1%), and as tumor-infiltrating immune cells (IC) 3 (≥ 50%), IC2 (5-49%), IC1 (1-4%), or IC0 (< 1%) for PD-L1. Expression level was compared between none-mild/moderate-severe total emphysema, no/presence of local emphysema, no COPD/COPD, and GOLD 1/GOLD 2, 3. RESULTS: PD-L1 expression was significantly correlated with severity of emphysema in TC0, 1, 2 vs. TC3 (P = 0.012). PD-L1 was significantly higher inversely in none-mild emphysema compared to moderate-severe (95% CI, 0.061-5.852, P = 0.045). There were no other significant associations between PD-L1, FGFR1, PIK3CA, PTEN, and p16 expression and total/local severity of emphysema or presence of COPD/GOLD stage. CONCLUSIONS: PD-L1 expression in SCC was correlated with severity of emphysema in TC0, 1, 2 vs. TC3 and more frequent in none-mild emphysema than moderate-severe emphysema.

Interactions Between the Gravitostat and the Fibroblast Growth Factor System for the Regulation of Body Weight.

Both fibroblast growth factors (FGFs), by binding to FGF receptors (FGFRs), and activation of the gravitostat, by artificial loading, decrease the body weight (BW). Previous studies demonstrate that both the FGF system and loading have the capacity to regulate BW independently of leptin. The aim of the current study was to determine the possible interactions between the effect of increased loading and the FGF system for the regulation of BW. We observed that the BW-reducing effect of increased loading was abolished in mice treated with a monoclonal antibody directed against FGFR1c, suggesting interactions between the two systems. As serum levels of endocrine FGF21 and hepatic FGF21 mRNA were increased in the loaded mice compared with the control mice, we first evaluated the loading response in FGF21 over expressing mice with constant high FGF21 levels. Leptin treatment, but not increased loading, decreased the BW in the FGF21-overexpressing mice, demonstrating that specifically the loading effect is attenuated in the presence of high activity in the FGF system. However, as FGF21 knockout mice displayed a normal loading response on BW, FGF21 is neither mediating nor essential for the loading response. In conclusion, the BW-reducing effect of increased loading but not of leptin treatment is blocked by high activity in the FGF system. We propose that both the gravitostat and the FGF system regulate BW independently of leptin and that pharmacologically enhanced activity in the FGF system reduces the sensitivity of the gravitostat.

Fibroblast growth factor receptor 5 (FGFR5) is a co-receptor for FGFR1 that is up-regulated in beta-cells by cytokine-induced inflammation.

Fibroblast growth factor receptor-1 (FGFR1) activity at the plasma membrane is tightly controlled by the availability of co-receptors and competing receptor isoforms. We have previously shown that FGFR1 activity in pancreatic beta-cells modulates a wide range of processes, including lipid metabolism, insulin processing, and cell survival. More recently, we have revealed that co-expression of FGFR5, a receptor isoform that lacks a tyrosine-kinase domain, influences FGFR1 responses. We therefore hypothesized that FGFR5 is a co-receptor to FGFR1 that modulates responses to ligands by forming a receptor heterocomplex with FGFR1. We first show here increased FGFR5 expression in the pancreatic islets of nonobese diabetic (NOD) mice and also in mouse and human islets treated with proinflammatory cytokines. Using siRNA knockdown, we further report that FGFR5 and FGFR1 expression improves beta-cell survival. Co-immunoprecipitation and quantitative live-cell imaging to measure the molecular interaction between FGFR5 and FGFR1 revealed that FGFR5 forms a mixture of ligand-independent homodimers (∼25%) and homotrimers (∼75%) at the plasma membrane. Interestingly, co-expressed FGFR5 and FGFR1 formed heterocomplexes with a 2:1 ratio and subsequently responded to FGF2 by forming FGFR5/FGFR1 signaling complexes with a 4:2 ratio. Taken together, our findings identify FGFR5 as a co-receptor that is up-regulated by inflammation and promotes FGFR1-induced survival, insights that reveal a potential target for intervention during beta-cell pathogenesis.

High Affinity Promotes Internalization of Engineered Antibodies Targeting FGFR1.

Fibroblast growth factor receptor 1 (FGFR1) is a plasma membrane protein that transmits signals from the extracellular environment, regulating cell homeostasis and function. Dysregulation of FGFR1 leads to the development of human cancers and noncancerous diseases. Numerous tumors overproduce FGFR1, making this receptor a perspective target for cancer therapies. Antibody-drug conjugates (ADCs) are highly potent and selective anticancer agents. ADCs are composed of antibodies (targeting factors) fused to highly cytotoxic drugs (warheads). The efficiency of ADC strategy largely depends on the internalization of cytotoxic conjugate into cancer cells. Here, we have studied an interplay between affinity of anti-FGFR1 antibodies and efficiency of their cellular uptake. We have developed a unique set of engineered anti-FGFR1 antibodies that bind the same epitope in the extracellular part of FGFR1, but with different affinities. We have demonstrated that these antibodies are effectively taken up by cancer cells in the FGFR1-dependent manner. Interestingly, we have found that efficiency, defined as rate and level of antibody internalization, largely depends on the affinity of engineered antibodies towards FGFR1, as high affinity antibody displays fastest internalization kinetics. Our data may facilitate design of therapeutically relevant targeting molecules for selective treatment of FGFR1 overproducing cancers.

Cardiovascular Effects of Renal Distal Tubule Deletion of the FGF Receptor 1 Gene.

The bone-derived hormone fibroblast growth factor-23 (FGF-23) activates complexes composed of FGF receptors (FGFRs), including FGFR1, and α-Klotho in the kidney distal tubule (DT), leading to increased sodium retention and hypertension. However, the role of FGFR1 in regulating renal processes linked to hypertension is unclear. Here, we investigated the effects of selective FGFR1 loss in the DT. Conditional knockout (cKO) of FGFR1 in the DT (FGFR1DT-cKO mice) resulted in left ventricular hypertrophy (LVH) and decreased kidney expression of α-Klotho in association with enhanced BP, decreased expression of angiotensin converting enzyme 2, and increased expression of the Na+-K+-2Cl- cotransporter. Notably, recombinant FGF-23 administration similarly decreased the kidney expression of α-Klotho and induced LVH in mice. Pharmacologic activation of FGFR1 with a monoclonal anti-FGFR1 antibody (R1MAb1) normalized BP and significantly attenuated LVH in the Hyp mouse model of excess FGF-23, but did not induce a response in FGFR1DT-cKO mice. The hearts of FGFR1DT-cKO mice showed increased expression of the transient receptor potential cation channel, subfamily C, member 6 (TRPC6), consistent with cardiac effects of soluble Klotho deficiency. Moreover, administration of recombinant soluble Klotho lowered BP in the Hyp mice. Thus, FGFR1 in the DT regulates systemic hemodynamic responses opposite to those predicted by the actions of FGF-23. These cardiovascular effects appear to be mediated by paracrine FGF control of kidney FGFR1 and subsequent regulation of soluble Klotho and TRPC6. FGFR1 in the kidney may provide a new molecular target for treating hypertension.

FGF21 mimetic antibody stimulates UCP1-independent brown fat thermogenesis via FGFR1/ßKlotho complex in non-adipocytes.

OBJECTIVE: Fibroblast Growth Factor 21 (FGF21) is a potent stimulator of brown fat thermogenesis that improves insulin sensitivity, ameliorates hepatosteatosis, and induces weight loss by engaging the receptor complex comprised of Fibroblast Growth Factor Receptor 1 (FGFR1) and the requisite coreceptor ßKlotho. Previously, recombinant antibody proteins that activate the FGFR1/ßKlotho complex were proposed to act as an FGF21-mimetic; however, in vivo action of these engineered proteins has not been well studied. METHODS: We investigated the mechanism by which anti-FGFR1/ßKlotho bispecific antibody (bFKB1) stimulates thermogenesis in UCP1-expressing brown adipocytes using genetically engineered mice. Anti-FGFR1 agonist antibody was also used to achieve brown adipose tissue restricted activation in transgenic mice. RESULTS: Studies with global Ucp1-deficient mice and adipose-specific Fgfr1 deficient mice demonstrated that bFKB1 acts on targets distal to adipocytes and indirectly stimulates brown adipose thermogenesis in a UCP1-independent manner. Using a newly developed transgenic system, we also show that brown adipose tissue restricted activation of a transgenic FGFR1 expressed under the control of Ucp1 promoter does not stimulate energy expenditure. Finally, consistent with its action as a FGF21 mimetic, bFBK1 suppresses intake of saccharin-containing food and alcohol containing water in mice. CONCLUSIONS: Collectively, we propose that FGFR1/ßKlotho targeted therapy indeed mimics the action of FGF21 in vivo and stimulates UCP1-independent brown fat thermogenesis through receptors outside of adipocytes and likely in the nervous system.

Peptide-Based Regulation of Metabolism as Related to Obesity.

Currently there are few, if any, approved and effective medicines for the attenuation of obesity, diabetes, and insulin resistance. This commentary addresses a communication describing the effect on glucose dynamics and obesity of a peptide monoclonal antibody for fibroblast growth factor (FGF) receptor 1c isoform (FGFR1c). The general lack of suitable, effective drugs is discussed, as is the treatment potential of FGF family receptors. The FGFR1c monoclonal antibody developed by the authors lowers body weight gain, blood glucose, and adipose tissue weight. It also enhances glucose uptake by fat cells [white adipose tissue (WAT) and 3T3-L1]. The robust weight loss, fat loss, and lower blood glucose were attributed to an observed potential futile cycle of continuous lipogenesis and lipolysis and adenosine triphosphate use in WAT.

Tethered-variable CL bispecific IgG: an antibody platform for rapid bispecific antibody screening.

Bispecific antibodies offer a clinically validated platform for drug discovery. In generating functionally active bispecific antibodies, it is necessary to identify a unique parental antibody pair to merge into a single molecule. However, technologies that allow high-throughput production of bispecific immunoglobulin Gs (BsIgGs) for screening purposes are limited. Here, we describe a novel bispecific antibody format termed tethered-variable CLBsIgG (tcBsIgG) that allows robust production of intact BsIgG in a single cell line, concurrently ensuring cognate light chain pairing and preserving key antibody structural and functional properties. This technology is broadly applicable in the generation of BsIgG from a variety of antibody isotypes, including human BsIgG1, BsIgG2 and BsIgG4. The practicality of the tcBsIgG platform is demonstrated by screening BsIgGs generated from FGF21-mimetic anti-Klotho-ß agonistic antibodies in a combinatorial manner. This screen identified multiple biepitopic combinations with enhanced agonistic activity relative to the parental monoclonal antibodies, thereby demonstrating that biepitopic antibodies can acquire enhanced functionality compared to monospecific parental antibodies. By design, the tcBsIgG format is amenable to high-throughput production of large panels of bispecific antibodies and thus can facilitate the identification of rare BsIgG combinations to enable the discovery of molecules with improved biological function.

FGF19, FGF21, and an FGFR1/ß-Klotho-Activating Antibody Act on the Nervous System to Regulate Body Weight and Glycemia.

Despite the different physiologic functions of FGF19 and FGF21 as hormonal regulators of fed and fasted metabolism, their pharmacologic administration causes similar increases in energy expenditure, weight loss, and enhanced insulin sensitivity in obese animals. Here, in genetic loss-of-function studies of the shared co-receptor ß-Klotho, we show that these pharmacologic effects are mediated through a common, tissue-specific pathway. Surprisingly, FGF19 and FGF21 actions in liver and adipose tissue are not required for their longer-term weight loss and glycemic effects. In contrast, ß-Klotho in neurons is essential for both FGF19 and FGF21 to cause weight loss and lower glucose and insulin levels. We further show an FGF21 mimetic antibody that activates the FGF receptor 1/ß-Klotho complex also requires neuronal ß-Klotho for its metabolic effects. These studies highlight the importance of the nervous system in mediating the beneficial weight loss and glycemic effects of endocrine FGF drugs.

Antibody-Mediated Targeting of the FGFR1c Isoform Increases Glucose Uptake in White and Brown Adipose Tissue in Male Mice.

The increased prevalence of obesity and its cardiometabolic implications demonstrates the imperative to identify novel therapeutic targets able to effect meaningful metabolic changes in this population. Antibody-mediated targeting of fibroblast growth factor receptor 1c isoform (FGFR1c) has been shown to ameliorate hyperglycemia and protect from diet- and genetically-induced obesity in rodents and nonhuman primates. However, it is currently unknown which tissue(s) contribute to this glucose-lowering effect. Thus, to elucidate this effect, we treated euglycemic mice with H7, a monoclonal antibody that selectively targets FGFR1c, and used whole-body positron emission computed tomography with a glucose tracer (18F-fluorodeoxyglucose). Treatment with H7 increased basal glucose uptake in white adipose tissue (WAT), brown adipose tissue (BAT), the brain, and liver but reduced it in the quadriceps muscles. Consequentially, blood glucose was significantly reduced in response to treatment. Under insulin-stimulated conditions, the effects of H7 were maintained in WAT, BAT, liver, and muscle. Treatment with H7 decreased triglyceride (TG) content and increased adipose TG lipase content in white adipose tissue, while increasing activation of acetyl coenzyme A carboxylase, suggesting futile cycling of TGs, albeit favoring net hydrolysis. We demonstrated, in vitro, this is a direct effect of treatment in adipose tissue, as basal cellular respiration and glucose uptake were increased in response to treatment. Taken together, these data suggest that antibody-mediated targeting of FGFR1c exerts its powerful glucose-lowering efficacy primarily due to increased glucose uptake in adipose tissue.

Basic Fibroblast Growth Factor 2 Is a Determinant of CD4 T Cell-Airway Smooth Muscle Cell Communication through Membrane Conduits.

Activated CD4 T cells connect to airway smooth muscle cells (ASMCs) in vitro via lymphocyte-derived membrane conduits (LMCs) structurally similar to membrane nanotubes with unknown intercellular signals triggering their formation. We examined the structure and function of CD4 T cell-derived LMCs, and we established a role for ASMC-derived basic fibroblast growth factor 2 (FGF2b) and FGF receptor (FGFR)1 in LMC formation. Blocking FGF2b's synthesis and FGFR1 function reduced LMC formation. Mitochondrial flux from ASMCs to T cells was partially FGF2b and FGFR1 dependent. LMC formation by CD4 T cells and mitochondrial transfer from ASMCs was increased in the presence of asthmatic ASMCs that expressed more mRNA for FGF2b compared with normal ASMCs. These observations identify ASMC-derived FGF2b as a factor needed for LMC formation by CD4 T cells, affecting intercellular communication.

Preclinical pharmacokinetic characterization of an adipose tissue-targeting monoclonal antibody in obese and non-obese animals.

Target receptor levels can influence pharmacokinetics (PK) or pharmacodynamics (PD) of monoclonal antibodies (mAbs), and can affect drug development of this class of molecules. We generated an effector-less humanized bispecific antibody that selectively activates fibroblast growth factor receptor (FGFR)1 and ßKlotho receptor, a FGF21 receptor complex highly expressed in both white and brown adipocytes. The molecule shows cross-species binding with comparable equilibrium binding affinity (Kd) for human, cynomolgus monkey, and mouse FGFR1/ßKlotho. To understand the PK/PD relationship in non-obese and obese animals, we evaluated the adipose tissue distribution of the antibody, serum exposures, and an associated PD marker (high-molecular-weight adiponectin), in both non-obese and obese mice and monkeys. Antibody uptake into fat tissue was found to be higher on a per gram basis in non-obese animals compared to obese animals. Since obesity has been reported to be associated with reduced expression of FGFR1 and ßKlotho receptor in white adipose tissues in mice, our results suggest that the distribution in adipose tissues was influenced by target expression levels. Even so, the overall dose-normalized serum exposures were comparable between non-obese and obese mice and monkeys, suggesting that adipose tissue uptake plays a limited role in overall systemic PK determination. It remains to be determined if and how obesity and receptor expression in humans influence the PK and PD profile of this novel therapeutic candidate.

High-Affinity Internalizing Human scFv-Fc Antibody for Targeting FGFR1-Overexpressing Lung Cancer.

Targeted delivery of anticancer drugs using antibodies specific for tumor-associated antigens represents one of the most important approaches in current immuno-oncology research. Fibroblast growth factor receptor 1 (FGFR1) has been demonstrated to be a high-frequency targetable oncogene specific for smoking-associated lung cancers, present in over 20% of lung squamous cell carcinoma cases. This report describes the generation of a potent, fully human antibody fragment in scFv-Fc format efficiently targeting FGFR1. Antibody phage display was used to select high-affinity scFv antibody fragments against the extracellular domain of FGFR1(IIIc). Enzyme immunoassay (ELISA) and surface plasmon resonance (SPR) analysis were used for antibody screening and characterization. The best binder (named D2) was cloned to diabody and Fc fusion formats. All D2 antibodies demonstrated high affinity for FGFR1 with dissociation constants of 18 nmol/L (scFvD2), 0.82 nmol/L (scFvD2 diabody), and 0.59 nmol/L (scFvD2-Fc). scFvD2 was found to be exquisitely selective for FGFR1 versus other FGFR family members and bound FGFR1 even in the presence of its natural ligand FGF2, as shown by competitive analysis. Confocal microscopy revealed that scFvD2-Fc was specifically and rapidly internalized by a panel of cell lines overexpressing FGFR1. Finally, it was demonstrated that scFvD2-Fc mediated specific delivery of a cytotoxic payload into lung cancer cells harboring oncogenic FGFR1 gene amplifications.Implications: This study reports a highly specific internalizing antibody fragment that can serve as a therapeutic targeting agent for efficient delivery of cytotoxic drugs into FGFR1-positive lung cancer cells. Mol Cancer Res; 15(8); 1040-50. ©2017 AACR.

An efficient route to bispecific antibody production using single-reactor mammalian co-culture.

Bispecific antibodies have shown promise in the clinic as medicines with novel mechanisms of action. Lack of efficient production of bispecific IgGs, however, has limited their rapid advancement. Here, we describe a single-reactor process using mammalian cell co-culture production to efficiently produce a bispecific IgG with 4 distinct polypeptide chains without the need for parallel processing of each half-antibody or additional framework mutations. This method resembles a conventional process, and the quality and yield of the monoclonal antibodies are equal to those produced using parallel processing methods. We demonstrate the application of the approach to diverse bispecific antibodies, and its suitability for production of a tissue specific molecule targeting fibroblast growth factor receptor 1 and klotho ß that is being developed for type 2 diabetes and other obesity-linked disorders.

Analysis of multipotent mesenchymal stromal cells used for acute graft-versus-host disease prophylaxis.

BACKGROUND: Multipotent mesenchymal stromal cells (MSCs) are used for prophylaxis of acute graft-versus-host disease (aGvHD) after allogeneic hematopoietic cell transplantation (allo-HCT). Not all samples of MSC are efficient for aGvHD prevention. The suitability of MSCs for aGvHD prophylaxis was studied. METHODS: MSCs were derived from the bone marrow (BM) of HCT donor and cultivated for no more than three passages. The characteristics of donor BM samples including colony-forming unit fibroblast (CFU-F) concentration, growth parameters of MSCs, and the relative expression levels (REL) of different genes were analyzed. MSCs were injected intravenously precisely at the moment of blood cell reconstitution. RESULTS: MSCs infusion induced a significant threefold decrease in aGvHD development and improved overall survival compared with the standard prophylaxis group. In ineffective MSC samples (9.4%), a significant decrease in total cell production and the REL of CSF1, FGFR1, and PDGFRB was observed. In all studied BM samples, the cumulative MSC production and CFU-F concentrations decreased with age. The expression levels of FGFR2, PPARG, and VEGF differed by age. CONCLUSIONS: A universal single indicator for the prediction of MSC eligibility for aGvHD prophylaxis was not identified. A multiparameter mathematical model for selecting MSC samples effective for the prevention of aGvHD was proposed.

Antibody-Mediated Inhibition of the FGFR1c Isoform Induces a Catabolic Lean State in Siberian Hamsters.

Hypothalamic tanycytes are considered to function as sensors of peripheral metabolism. To facilitate this role, they express a wide range of receptors, including fibroblast growth factor receptor 1 (FGFR1). Using a monoclonal antibody (IMC-H7) that selectively antagonizes the FGFR1c isoform, we investigated possible actions of FGFR1c in a natural animal model of adiposity, the Siberian hamster. Infusion of IMC-H7 into the third ventricle suppressed appetite and increased energy expenditure. Likewise, peripheral treatment with IMC-H7 decreased appetite and body weight and increased energy expenditure and fat oxidation. A greater reduction in body weight and caloric intake was observed in response to IMC-H7 during the long-day fat state as compared to the short-day lean state. This enhanced response to IMC-H7 was also observed in calorically restricted hamsters maintained in long days, suggesting that it is the central photoperiodic state rather than the peripheral adiposity that determines the response to FGFR1c antagonism. Hypothalamic thyroid hormone availability is controlled by deiodinase enzymes (DIO2 and DIO3) expressed in tanycytes and is the key regulator of seasonal cycles of energy balance. Therefore, we determined the effect of IMC-H7 on hypothalamic expression of these deiodinase enzymes. The reductions in food intake and body weight were always associated with decreased expression of DIO2 in the hypothalamic ependymal cell layer containing tanycytes. These data provide further support for the notion the tanycytes are an important component of the mechanism by which the hypothalamus integrates central and peripheral signals to regulate energy intake and expenditure.

Accumulation and activation of epidermal γδ T cells in a mouse model of chronic dermatitis is not required for the inflammatory phenotype.

Chronic skin inflammation resulting from a defective epidermal barrier is a hallmark of atopic dermatitis (AD). We previously demonstrated that mice lacking FGF receptors 1 and 2 in keratinocytes (K5-R1/R2 mice) develop an AD-like chronic dermatitis as a result of an impaired epidermal barrier. Here, we show that γδ T cells, which rapidly respond to various insults, accumulate in the epidermis of K5-R1/R2 mice before the development of histological abnormalities. Their number and activation further increase as the phenotype progresses, most likely as a consequence of increased expression of Il-2 and Il-7 and the stress-induced proteins Rae-1, H60c, Mult1, PlexinB2, and Skint1. To determine the role of γδ T cells in the skin phenotype, we generated quadruple mutant K5-R1/-R2 mice lacking γδ T cells. Surprisingly, loss of γδ T cells did not or only marginally affect keratinocyte proliferation, epidermal thickness, epidermal barrier function, and accumulation and activation of different immune cells in the skin of K5-R1/R2 mice, possibly due to partial compensation by αß T cells. These results demonstrate that γδ T cells do not contribute to the development or maintenance of chronic inflammation in response to a defect in the epidermal barrier.

OM-RCA-01, a novel humanized monoclonal antibody targeting fibroblast growth factor receptor 1, in renal cell carcinoma model.

Fibroblast growth factor (FGF) receptor 1 (FGFR1) is a potential therapeutic target for treatment of metastatic renal cell carcinoma (RCC). We investigated the preclinical activity of OM-RCA-01, a novel therapeutic humanized anti-FGFR1 antibody in RCC. OM-RCA-01 has been shown to inhibit in vitro kinase activity of FGFR1 and has high affinity (Kd of 1.59 nM). In human renal carcinoma Caki-1 FGFR1-expressing cells, OM-RCA-01 potently inhibited FGF-mediated signaling and proliferation. In vivo, the tumors in untreated mice or mice treated with non-specific IgG continued their aggressive growth to reach the size of 2,000 cm3, at which point the mice were killed. In contrast, treatment with OM-RCA-01 not only significant arrested further growth of the tumors (P < 0.01) but also demonstrated differences in tumor volume compared with vehicle already on Day 13. A similar anti-tumor activity of OM-RCA-01 was observed when the antibody was given in low (1 mg/kg) or high (10 mg/kg) doses (P = 0.917). In Matrigel assay, OM-RCA-01 significantly inhibited FGF-induced endothelial cell migration, capillary-like tubular structure and mature vessels formation. Administration of 10 mg/kg antibody for up to 35 days resulted in minimal body weight loss and no observations of gross toxicity were made. Collectively, the data obtained with OM-RCA-01 are consistent with potent inhibition of FGFR1-signaling, angiogenesis, and tumor growth. OM-RCA-01 is being developed clinically as an intravenous therapy for the treatment of clear cell RCC.