The heart provides the body with oxygen and nutrients and assists in the removal of metabolic waste through the blood vessels of the circulatory system. It is the first organ to form during embryonic morphogenesis. FGFs with diverse functions in development, health, and disease are signaling proteins, mostly as paracrine growth factors or endocrine hormones. The human/mouse FGF family comprises 22 members. Findings obtained from mouse models and human diseases with FGF signaling disorders have indicated that several FGFs are involved in heart development, health, and disease. Paracrine FGFs including FGF8, FGF9, FGF10, and FGF16 act as paracrine signals in embryonic heart development. In addition, paracrine FGFs including FGF2, FGF9, FGF10, and FGF16 play roles as paracrine signals in postnatal heart pathophysiology. Although FGF15/19, FGF21, and FGF23 are typical endocrine FGFs, they mainly function as paracrine signals in heart development or pathophysiology. In heart diseases, serum FGF15/19 levels or FGF21 and FGF23 levels decrease or increase, respectively, indicating their possible roles in heart pathophysiology. FGF2 and FGF10 also stimulate the cardiac differentiation of cultured stem cells and cardiac reprogramming of cultured fibroblasts. These findings provide new insights into the roles of FGF signaling in the heart and potential therapeutic strategies for cardiac disorders.

Fibroblast growth factors (Fgfs) are polypeptide growth factors with diverse biological activities. While several studies have revealed that Fgf23 plays important roles in the regulation of phosphate and vitamin D metabolism, the additional physiological roles of Fgf23 remain unclear. Although it is believed that osteoblasts/osteocytes are the main sources of Fgf23, we previously found that Fgf23 mRNA is also expressed in the mouse thymus, suggesting that it might be involved in the immune system. In this study we examined the potential roles of Fgf23 in immunological responses. Mouse serum Fgf23 levels were significantly increased following inoculation with Escherichia coli or Staphylococcus aureus or intraperitoneal injection of lipopolysaccharide. We also identified activated dendritic cells and macrophages that potentially contributed to increased serum Fgf23 levels. Nuclear factor-kappa B (NF-κB) signaling was essential for the induction of Fgf23 expression in dendritic cells in response to immunological stimuli. Moreover, we examined the effects of recombinant Fgf23 protein on immune cells in vitro. Fgfr1c, a potential receptor for Fgf23, was abundantly expressed in macrophages, suggesting that Fgf23 might be involved in signal transduction in these cells. Our data suggest that Fgf23 potentially increases the number in macrophages and induces expression of tumor necrosis factor-α (TNF-α), a proinflammatory cytokine. Collectively, these data suggest that Fgf23 might be intimately involved in inflammatory processes.Key words fibroblast growth factor (Fgf); Fgf23; macrophage; dendritic cell; inflammationThe fibroblast growth factors (Fgfs) family consists of 22 polypeptide growth factors that are widely expressed in developing and adult tissues and regulate diverse biological processes, including angiogenesis, mitogenesis, cellular differentiation, and tissue repair. 1,2) Fgfs can be classified into three groups, canonical, intracellular, and hormone-like Fgfs. The canonical Fgfs bind to and activate Fgf receptors (Fgfrs) on the cell surface, resulting in the activation of several cytoplasmic signal transduction pathways. These canonical Fgfs function in a paracrine manner. The intracellular Fgfs act as intracellular signaling molecules in an Fgfr-independent manner. Hormone-like Fgfs, including Fgf15/19, Fgf21, and Fgf23, depends on Fgfrs to elicit biological responses, although they potentially function in an endocrine manner. 3) One of these hormone-like Fgfs, Fgf23, was originally identified in mice and humans by a DNA database search and was a well-known physiological regulator of phosphate and vitamin D metabolisms. [3][4][5][6] Fgf23 is produced by osteoblasts/osteocytes in response to 1,25-dihydroxyvitamine D, the biologically active form of vitamin D. 3,5,6) Secreted Fgf23 increases urinary phosphate excretion by reducing luminal expression of sodium-phosphate co-transporters in the proximal tubule. Secreted Fgf23 also attenuates systemic levels of 1,25-dihydroxyvitamine D, which stimulates phosphate...

Fibroblast growth factor (Fgf) signaling plays important roles in brain development. Fgf3 and Fgf8 are crucial for the formation of the forebrain and hindbrain. Fgf8 is also required for the midbrain to form. Here, we identified zebrafish Fgf19 and examined its roles in brain development by knocking down Fgf19 function. We found that Fgf19 expressed in the forebrain, midbrain and hindbrain was involved in cell proliferation and cell survival during embryonic brain development. Fgf19 was also essential for development of the ventral telencephalon and diencephalon. Regional specification is linked to cell type specification. Fgf19 was also essential for the specification of gamma-aminobutyric acid (GABA)ergic interneurons and oligodendrocytes generated in the ventral telencephalon and diencephalon. The cross talk between Fgf and Hh signaling is critical for brain development. In the forebrain, Fgf19 expression was down-regulated on inhibition of Hh but not of Fgf3/Fgf8, and overexpression of Fgf19 rescued partially the phenotype on inhibition of Hh. The present findings indicate that Fgf19 signaling is crucial for forebrain development by interacting with Hh and provide new insights into the roles of Fgf signaling in brain development.

Neudesin is a secreted protein with neurotrophic activity in neurons and undifferentiated neural cells. We report here that neudesin is an extracellular heme-binding protein and that its neurotrophic activity is dependent on the binding of heme to its cytochrome b 5 -like heme/steroid-binding domain. At first, we found that at least a portion of the purified recombinant neudesin appeared to bind hemin because the purified neudesin solution was tinged with green and had a sharp absorbance peak at 402 nm. The addition of exogenous hemin extensively increased the amount of heminbound neudesin. In contrast, neudesin⌬HBD, a mutant lacking the heme-binding domain, could not bind hemin.

Progesterone receptor membrane component 1 (PGRMC1), PGRMC2, neudesin, and neuferricin all contain a cytochrome b5-like heme/steroid-binding domain and belong to the membrane-associated progesterone receptor (MAPR) family. Their amino acid sequences are well conserved among vertebrates, from humans to zebrafish. MAPR family genes are abundantly expressed in the central nervous system and exhibit neurotrophic effects in neural cells. During lipid metabolism, PGRMC1 regulates cholesterol synthesis, and neudesin plays a role in adipogenesis. Their bioactivities are dependent on the binding of heme to their cytochrome b5-like heme/steroid-binding domains. Conversely, it has been reported that the binding of steroids to MAPR family proteins induces biological responses that are unrelated to the nuclear steroid receptors. The interaction between PGRMC1 and progesterone promotes cell survival and damage resistance by progesterone. Moreover, MAPR family proteins exhibit a unique expression pattern in breast cancer, indicating the possibility of using MAPR family members as drug target in breast cancer. In this review, we summarize the identification, structure, and bioactivity of members of the MAPR family, and present an essential overview of the current understanding of their physiological roles.

The liver plays important roles in multiple processes including metabolism, the immune system, and detoxification and also has a unique capacity for regeneration. FGFs are growth factors that have diverse functions in development, health, and disease. The FGF family now comprises 22 members. Several FGFs have been shown to play roles as paracrine signals in liver development, health, and disease. FGF8 and FGF10 are involved in embryonic liver development, FGF7 and FGF9 in repair in response to liver injury, and FGF5, FGF8, FGF9, FGF17, and FGF18 in the development and progression of hepatocellular carcinoma. In contrast, FGF15/19 and FGF21 are endocrine signals. FGF15/19, which is produced in the ileum, is a negative regulator of bile acid metabolism and a stimulator of gallbladder filling. FGF15/19 is a postprandial, insulin-independent activator of hepatic protein and glycogen synthesis. It is also required for hepatocellular carcinoma and liver regeneration. FGF21 is a hepatokine produced in the liver. FGF21 regulates glucose and lipid metabolism in white adipose tissue. Serum FGF21 levels are elevated in non-alcoholic fatty liver. FGF21 also protects against non-alcoholic fatty liver. These findings provide new insights into the roles of FGFs in the liver and potential therapeutic strategies for hepatic disorders.

The unbound excited states of the neutron drip-line isotope 24 O have been investigated via the 24 O(p,p ) 23 O+n reaction in inverse kinematics at a beam energy of 62 MeV/nucleon. The decay energy spectrum of 24 O * was reconstructed from the momenta of 23 O and the neutron. The spinparity of the first excited state, observed at Ex = 4.65 ± 0.14 MeV, was determined to be J π = 2 + from the angular distribution of the cross section. Higher-lying states were also observed. The quadrupole transition parameter β2 of the 2 Otsuka et al. have investigated theoretically the structural evolution of the oxygen isotopes with increasing neutron number (N ) and attributed the development of the shell closure at N = 16 to the strong neutron-proton tensor interaction [10,11].In this Letter we report on the first spectroscopic study of 24 O by proton inelastic scattering. In addition to the excitation energies of the states populated, the wellknown character of proton inelastic scattering also permits the spins-parities, as well as the quadrupole transition parameter (β 2 ) of the first 2 + state to be deduced. As described below, we have been able to provide a firm 2 + assignment for the state at E x = 4.65 ± 0.14 MeV and determine the β 2 , the small value of which is indicative of the spherical closed-shell character of 24 O. A comparison of the E x (2 + 1 ) and β 2 for the chain of oxygen isotopes shows strong evidence for a large shell gap at N = 16.The experiment was performed at the RIPS facility [17] at RIKEN. A schematic view of the downstream section of RIPS and the experimental setup is shown in Fig. 1

J. Neurochem. (2010) 112, 1156–1167. Abstract We identified a novel extracellular heme‐binding protein and named it neuferricin. The recombinant mouse neuferricin produced in High Five cells was secreted efficiently into the culture medium. Mouse neuferricin mRNA was expressed mainly in the brain at the embryo stage and gradually increased during development. At postnatal stage, it was widely expressed in the brain, heart, adrenal gland, and kidney. Mouse neuferricin has 263 amino acids. It has a cytochrome b5‐like heme/steroid‐binding domain and appeared to bind hemin because neuferricin solution, but not a solution of neuferricinΔHBD (a mutant lacking the heme‐binding domain), was tinged with brown and had an absorbance peak at 402 nm. In addition, the experiment with anti‐neuferricin antibody using heme‐affinity chromatography proved that the endogenous neuferricin detected in the culture medium of Neuro2a cells was associated with hemin. Inhibition of endogenous neuferricin by RNA interference excessively promoted cell survival and proliferation and suppressed neurite outgrowth during the induction of differentiation in Neuro2a cells. Addition of recombinant mouse neuferricin, but not neuferricinΔHBD, suppressed survival of Neuro2a cells and rescued from the effects of neuferricin RNAi. In primary cultured mouse neural precursor cells, recombinant mouse neuferricin exhibited the ability to promote neurogenesis. The identification of neuferricin, a novel extracellular heme‐binding protein with cytochrome b5‐like heme/steroid‐binding domain and its neurogenic activity, provide new insights not only into brain development but also the function of heme‐binding proteins as extracellular signal transmitters.