FGF-18 is a neuron-derived glial cell growth factor expressed in the rat brain during early postnatal development

FGF-18 Protects the Injured Spinal cord in mice by Suppressing Pyroptosis and Promoting Autophagy via the AKT-mTOR-TRPML1 axis

Spinal cord injury (SCI) is a severe medical condition with lasting effects. The efficacy of numerous clinical treatments is hampered by the intricate pathophysiological mechanism of SCI. Fibroblast growth factor 18 (FGF-18) has been found to exert neuroprotective effects after brain ischaemia, but its effect after SCI has not been well explored. The aim of the present study was to explore the therapeutic effect of FGF-18 on SCI and the related mechanism. In the present study, a mouse model of SCI was used, and the results showed that FGF-18 may significantly affect functional recovery. The present findings demonstrated that FGF-18 directly promoted functional recovery by increasing autophagy and decreasing pyroptosis. In addition, FGF-18 increased autophagy, and the well-known autophagy inhibitor 3-methyladenine (3MA) reversed the therapeutic benefits of FGF-18 after SCI, suggesting that autophagy mediates the therapeutic effects of FGF-18 on SCI. A mechanistic study revealed that after stimulation of the protein kinase B (AKT)-transient receptor potential mucolipin 1 (TRPML1)-calcineurin signalling pathway, the FGF-18-induced increase in autophagy was mediated by the dephosphorylation and nuclear translocation of transcription factor E3 (TFE3). Together, these findings indicated that FGF-18 is a robust autophagy modulator capable of accelerating functional recovery after SCI, suggesting that it may be a promising treatment for SCI in the clinic.

The role of microglial activation on ischemic stroke: Modulation by fibroblast growth factors

Stroke is one of the devastating clinical conditions that causes death and permanent disability. Its occurrence causes the reduction of oxygen and glucose supply, resulting in events such as inflammatory response, oxidative stress, and apoptosis in the brain. Microglia are brain-resident immune cells in the central nervous system (CNS) that exert diverse roles and respond to pathological process after an ischemic insult. The discovery of fibroblast growth factors (FGFs) in mammals, resulted to the findings that they can treat experimental models of stroke in animals effectively. FGFs function as homeostatic factors that control cells and hormones involved in metabolism, and they also regulate the secretion of proinflammatory (M1) and anti-inflammatory (M2) cytokines after stroke. In this review, we outline current evidence of microglia activation in experimental models of stroke focusing on its ability to exacerbate damage or repair tissue. Also, our review sheds light on the pharmacological actions of FGFs on multiple targets to regulate microglial modulation and highlighted their theoretical molecular mechanisms to provide possible therapeutic targets, as well as their limitations for the treatment of stroke. DATA AVAILABILITY: Not applicable.

Joint multi-ancestry and admixed GWAS reveals the complex genetics behind human cranial vault shape

The cranial vault in humans is highly variable, clinically relevant, and heritable, yet its genetic architecture remains poorly understood. Here, we conduct a joint multi-ancestry and admixed multivariate genome-wide association study on 3D cranial vault shape extracted from magnetic resonance images of 6772 children from the ABCD study cohort yielding 30 genome-wide significant loci. Follow-up analyses indicate that these loci overlap with genomic risk loci for sagittal craniosynostosis, show elevated activity cranial neural crest cells, are enriched for processes related to skeletal development, and are shared with the face and brain. We present supporting evidence of regional localization for several of the identified genes based on expression patterns in the cranial vault bones of E15.5 mice. Overall, our study provides a comprehensive overview of the genetics underlying normal-range cranial vault shape and its relevance for understanding modern human craniofacial diversity and the etiology of congenital malformations.

FGF18

FGF18 was discovered in 1998. It is a pleiotropic growth factor that stimulates major signalling pathways involved in cell proliferation and growth, and is involved in the development and homeostasis of many tissues such as bone, lung, and central nervous system. The gene consists of five exons that code for a 207 amino acid glycosylated protein. FGF18 is widely expressed in developing and adult chickens, mice, and humans, being seen in the mesenchyme, brain, skeleton, heart, and lungs. Knockout studies of FGF18 in mice lead to perinatal death, characterised by distinct phenotypes such as cleft palate, smaller body size, curved long bones, deformed ribs, and reduced crania. As can be expected from a protein involved in so many functions FGF18 is associated with various diseases such as idiopathic pulmonary fibrosis, congenital diaphragmatic hernia, and most notably various types of cancer such as breast, lung, and ovarian cancer.

FGF-18 alleviates memory impairments and neuropathological changes in a rat model of Alzheimer's disease

Alzheimer's disease (AD) is a multifactorial pathology marked by amyloid beta (Aβ) accumulation, tau hyperphosphorylation, and progressive cognitive decline. Previous studies show that fibroblast growth factor 18 (FGF18) exerts a neuroprotective effect in experimental models of neurodegeneration; however, how it affects AD pathology remains unknown. This study aimed to ascertain the impact of FGF18 on the behavioral and neuropathological changes in the rat model of sporadic AD induced by intracerebroventricular (ICV) injection of streptozotocin (STZ). The rats were treated with FGF18 (0.94 and 1.88 pmol, ICV) on the 15th day after STZ injection. Their cognitive function was assessed in the Morris water maze and passive avoidance tests for 5 days from the 16th to the 21st days. Aβ levels and histological signs of neurotoxicity were detected using the enzyme-linked immunosorbent assay (ELISA) assay and histopathological analysis of the brain, respectively. FGF18 mildly ameliorated the STZ-induced cognitive impairment; the Aβ accumulation was reduced; and the neuronal damage including pyknosis and apoptosis was alleviated in the rat brain. This study highlights the promising therapeutic potential for FGF18 in managing AD.

Circulating FGF18 is decreased in pleural mesothelioma but not correlated with disease prognosis

BACKGROUND

Pleural mesothelioma (PM) is a relatively rare malignancy with limited treatment options and dismal prognosis. We have previously found elevated FGF18 expression in PM tissue specimens compared with normal mesothelium. The objective of the current study was to further explore the role of FGF18 in PM and evaluate its suitability as a circulating biomarker.

METHODS

FGF18 mRNA expression was analyzed by real-time PCR in cell lines and in silico in datasets from the Cancer Genome Atlas (TCGA). Cell lines overexpressing FGF18 were generated by retroviral transduction and cell behavior was investigated by clonogenic growth and transwell assays. Plasma was collected from 40 PM patients, six patients with pleural fibrosis, and 40 healthy controls. Circulating FGF18 was measured by ELISA and correlated to clinicopathological parameters.

RESULTS

FGF18 showed high mRNA expression in PM and PM-derived cell lines. PM patients with high FGF18 mRNA expression showed a trend toward longer overall survival (OS) in the TCGA dataset. In PM cells with low endogenous FGF18 expression, forced overexpression of FGF18 resulted in reduced growth but increased migration. Surprisingly, despite the high FGF18 mRNA levels observed in PM, circulating FGF18 protein was significantly lower in PM patients and patients with pleural fibrosis than in healthy controls. No significant association of circulating FGF18 with OS or other disease parameters of PM patients was observed.

CONCLUSIONS

FGF18 is not a prognostic biomarker in PM. Its role in PM tumor biology and the clinical significance of decreased plasma FGF18 in PM patients warrant further investigation.

Roles of Fibroblast Growth Factors and Their Therapeutic Potential in Treatment of Ischemic Stroke

Stroke is the leading cause of death worldwide, and its treatment remains a challenge. Complex pathological processes are involved in stroke, which causes a reduction in the supply of oxygen and energy to the brain that triggers subsequent cascade events, such as oxidative stress, inflammatory responses and apoptosis, resulting in brain injury. Stroke is a devastating disease for which there are few treatments, but physical rehabilitation can help improve stroke recovery. Although there are very few treatments for stroke patients, the discovery of fibroblast growth factors (FGFs) in mammals has led to the finding that FGFs can effectively treat stroke in animal models. As presented in this review, FGFs play essential roles by functioning as homeostatic factors and controlling cells and hormones involved in metabolism. They could be used as effective therapeutic agents for stroke. In this review, we will discuss the pharmacological actions of FGFs on multiple targets, including their ability to directly promote neuron survival, enhance angiogenesis, protect against blood-brain barrier (BBB) disruption, and regulate microglial modulation, in the treatment of ischemic stroke and their theoretical mechanisms and actions, as well as the therapeutic potential and limitations of FGFs for the clinical treatment of stroke.

Generation and validation of novel conditional flox and inducible Cre alleles targeting fibroblast growth factor 18 (Fgf18)

BACKGROUND

Fibroblast growth factor 18 (FGF18) functions in the development of several tissues, including the lung, limb bud, palate, skeleton, central nervous system, and hair follicle. Mice containing a germline knockout of Fgf18 (Fgf18 -/- ) die shortly after birth. Postnatally, FGF18 is being evaluated for pathogenic roles in fibrosis and several types of cancer. The specific cell types that express FGF18 have been difficult to identify, and the function of FGF18 in postnatal development and tissue homeostasis has been hampered by the perinatal lethality of Fgf18 null mice.

RESULTS

We engineered a floxed allele of Fgf18 (Fgf18 flox ) that allows conditional gene inactivation and a CreERT2 knockin allele (Fgf18 CreERT2 ) that allows the precise identification of cells that express Fgf18 and their lineage. We validated the Fgf18 flox allele by targeting it in mesenchymal tissue and primary mesoderm during embryonic development, resulting in similar phenotypes to those observed in Fgf18 null mice. We also use the Fgf18 CreERT2 allele, in combination with a conditional fluorescent reporter to confirm known and identify new sites of Fgf18 expression.

CONCLUSION

These alleles will be useful to investigate FGF18 function during organogenesis and tissue homeostasis, and to target specific cell lineages at embryonic and postnatal time points.

Lack of Fgf18 causes abnormal clustering of motor nerve terminals at the neuromuscular junction with reduced acetylcholine receptor clusters

FGF receptor 2 is involved in the formation of the neuromuscular junction (NMJ), but its in vivo ligand remains to be determined. Laser capture microdissection of the mouse spinal motor neurons (SMNs) revealed that Fgf18 mRNA is highly expressed in SMNs in adults. Expression of Fgf18 mRNA was the highest in the spinal cord at embryonic day (E) 15.5, which gradually decreased to postnatal day 7. FGF18 protein was localized at the NMJs of the tibialis anterior muscle at E18.5 and in adults. Fgf18−/− mice at E18.5 showed decreased expressions of the NMJ-specific Chrne and Colq genes in the diaphragm. In Fgf18−/− diaphragms, the synaptophysin-positive areas at the nerve terminals and the acetylcholine receptor (AChR)-positive areas at the motor endplates were both approximately one-third of those in wild-type embryos. Fgf18−/− diaphragms ultrastructurally showed abnormal aggregation of multiple nerve terminals making a gigantic presynapse with sparse synaptic vesicles, and simplified motor endplates. In Fgf18−/− diaphragms, miniature endplate potentials were low in amplitude with markedly reduced frequency. In C2C12 myotubes, FGF18 enhanced AChR clustering, which was blocked by inhibiting FGFRs or MEK1. We propose that FGF18 plays a pivotal role in AChR clustering and NMJ formation in mouse embryogenesis.

Autocrine fibroblast growth factor 18 signaling mediates Wnt-dependent stimulation of CD44-positive human colorectal adenoma cells

Expansion of a stem-like subpopulation with increased growth and survival potential is thought to drive colorectal tumor growth and progression. We investigated a CD44-positive (CD44((+))) subpopulation with extended growth and survival capacity in the human colon adenoma cell line LT97. This subpopulation expressed elevated levels of fibroblast growth factor 18 (FGF18) and fibroblast growth factor receptor FGFR3-IIIc. Expression levels of the FGFR3-IIIb, which does not bind FGF18, were similar in CD44((+)) and CD44((-)). Addition of FGF18 to the medium or its overexpression from an adenoviral vector increased the colony formation capacity of CD44((+)) threefold, and stimulated phosphorylation of ERK and GSK3β in both total LT97 populations and CD44((+)) cells. FGFR3 signaling blockade by expression of a dominant-negative FGFR3-IIIc mutant led to inhibition of both colony formation and down-stream signaling in the CD44((+)) cells. CD44((-)) cells did not respond. Blockade of the wnt-pathway by a dominant-negative Tcf4-mutant inhibited FGFR3 activation in LT97 cells as well as in HT29 colorectal cancer cells. The chemical wnt-inhibitor sulindac sulfide amide inhibited expression of FGF18 and FGFR3-IIIc and led to inhibition of receptor activation to less than 30% of control treated cells, both in LT97 and HT29 cultures. Our results demonstrate that an FGF18/FGFR3-IIIc autocrine growth and survival loop is up-regulated in a wnt-dependent manner and drives tumor cell growth in a subpopulation of colon adenoma cells. This subpopulation can be regarded as a precursor of colon cancer development and can be targeted for CRC-prevention by blocking either wnt- or FGFR3-signaling.

Physical-chemical principles underlying RTK activation, and their implications for human disease

RTKs, the second largest family of membrane receptors, exert control over cell proliferation, differentiation and migration. In recent years, our understanding of RTK structure and activation in health and disease has skyrocketed. Here we describe experimental approaches used to interrogate RTKs, and we review the quantitative biophysical frameworks and structural considerations that shape our understanding of RTK function. We discuss current knowledge about RTK interactions, focusing on the role of different domains in RTK homodimerization, and on the importance and challenges in RTK heterodimerization studies. We also review our understanding of pathogenic RTK mutations, and the underlying physical-chemical causes for the pathologies. This article is part of a Special Issue entitled: Protein Folding in Membranes.

Gene expression profile in rat dorsal root ganglion following sciatic nerve injury and systemic neurotrophin-3 administration

Following sciatic nerve transection in adult rats, a proportion of injured dorsal root ganglion (DRG) neurons die, through apoptosis, over the following 6 months. Previous studies showed that axotomy and neurotrophin-3 administration may have effects on expression of neurotrophins and their receptors in DRG. In the current study, the fourth and fifth lumbar DRGs of rats were examined 2 weeks after right sciatic nerve transection and ligation. The effects of axotomy and systemic NT-3 treatment on neuronal genes were investigated by microarray. The results demonstrated that bone morphogenetic protein (BMP) and Janus protein tyrosine kinase signaling pathways are induced in axotomized DRG, and PI-3 kinase and BMP pathways and genes controlling various cellular functions were induced after axotomy and NT-3 administration.

Expression and Functions of Fibroblast Growth Factor 2 (FGF-2) in Hippocampal Formation

Among the 23 members of the fibroblast growth factor (FGF) family, FGF-2 is the most abundant one in the central nervous system. Its impact on neural cells has been profoundly investigated by in vitro and in vivo studies as well as by gene knockout analyses during the past 2 decades. Key functions of FGF-2 in the nervous system include roles in neurogenesis, promotion of axonal growth, differentiation in development, and maintenance and plasticity in adulthood. From a clinical perspective, its prominent role for the maintenance of lesioned neurons (e.g., ischemia and following transection of fiber tracts) is of particular relevance. In the unlesioned brain, FGF-2 is involved in synaptic plasticity and processes attributed to learning and memory. The focus of this review is on the expression of FGF-2 and its receptors in the hippocampal formation and the physiological and pathophysiological roles of FGF-2 in this region during development and adulthood.

Neudesin, an extracellular heme-binding protein, suppresses adipogenesis in 3T3-L1 cells via the MAPK cascade

Adult mice abundantly express neudesin, an extracellular heme-binding protein with neurotrophic activity, in white adipose tissues. At the early stage of adipocyte differentiation during adipogenesis, however, the expression of neudesin decreased transiently. Neudesin-hemin significantly suppressed adipogenesis in 3T3-L1 cells. The knockdown of neudesin by RNA interference markedly promoted adipogenesis in 3T3-L1 cells and decreased MAPK activation during adipocyte differentiation. The addition or knockdown of neudesin affected the expression of C/EBPalpha and PPARgamma but not of C/EBPbeta. These findings suggest that neudesin plays a critical role in the early stage of adipocyte differentiation in which C/EBPbeta induces PPARgamma and C/EBPalpha expressions, by controlling the MAPK pathway.

A neutralizing anti-fibroblast growth factor (FGF) 8 monoclonal antibody shows anti-tumor activity against FGF8b-expressing LNCaP xenografts in androgen-dependent and -independent conditions

BACKGROUND

Fibroblast growth factor 8-isoform b (FGF8b) has been detected in human clinical sex-organ related cancers including hormone-refractory prostate cancer. There are, however, few relevant experimental models. A murine monoclonal anti-FGF8 antibody, KM1334, has been shown to neutralize FGF8b and inhibit the growth of androgen-dependent mouse mammary SC-3 cells in vitro and in vivo. In the present study, we evaluated the anti-tumor activity of KM1334 against androgen-dependent and -independent progression of FGF8b-expressing human prostate cancer xenografts.

METHODS

FGF8b cDNA was transfected into androgen-dependent human prostate cancer cell line LNCaP, and its xenograft tumors were established subcutaneously in SCID mice with or without castration. KM1334 at the dose of 400 microg/head was injected twice weekly.

RESULTS

FGF8b-expressing LNCaP cells secreted FGF8b, showed enhanced level of Erk1/2 phosphorylation, and showed more potent growth properties than mock-expressing cells in vitro and in vivo. KM1334 reduced these properties in vitro, inhibited tumorigenecity in vivo (T/C=0.33), and showed anti-tumor activity against established tumors (T/C=0.47) of FGF8b-expressing cells. FGF8b-expressing LNCaP tumors were androgen-dependent. However, they recurred as androgen-independent FGF8b positive tumors after castration. KM1334 also inhibited the growth of established FGF8b-expressing tumors in the androgen-independent states (T/C=0.47).

CONCLUSIONS

These results indicate that humanized monoclonal antibodies, conserving the paratope of KM1334, are a promising candidate for therapy of FGF8b-expressing clinical prostate cancers. Follow-up studies using xenograft models with clinical FGF8b-expressing tumors are required to validate these early findings.

Neurotrophic activity of neudesin, a novel extracellular heme-binding protein, is dependent on the binding of heme to its cytochrome b5-like heme/steroid-binding domain

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 hemin-bound neudesin. In contrast, neudesinDeltaHBD, a mutant lacking the heme-binding domain, could not bind hemin. The neurotrophic activity of the recombinant neudesin that bound exogenous hemin (neudesin-hemin) was significantly greater than that of the recombinant neudesin in either primary cultured neurons or Neuro2a cells, suggesting that the activity of neudesin depends on hemin. The neurotrophic activity of neudesin was enhanced by the binding of Fe(III)-protoporphyrin IX, but neither Fe(II)-protoporphyrin IX nor protoporphyrin IX alone. The inhibition of endogenous neudesin by RNA interference significantly decreased cell survival in Neuro2a cells. This indicates that endogenous neudesin possibly contains hemin. The experiment with anti-neudesin antibody suggested that the endogenous neudesin detected in the culture medium of Neuro2a cells was associated with hemin because it was not retained on a heme-affinity column at all. Neudesin is the first extracellular heme-binding protein that shows signal transducing activity by itself. The present findings may shed new light on the function of extracellular heme-binding proteins.

Decreased lung fibroblast growth factor 18 and elastin in human congenital diaphragmatic hernia and animal models

RATIONALE

Lung hypoplasia in congenital diaphragmatic hernia (CDH) seems to involve impaired alveolar septation. We hypothesized that disturbed deposition of elastin and expression of fibroblast growth factor 18 (FGF18), an elastogenesis stimulus, occurs in CDH.

OBJECTIVES

To document FGF18 and elastin in human CDH and ovine surgical and rat nitrofen models and to use models to evaluate the benefit of treatments.

METHODS

Human CDH and control lungs were collected post mortem. Diaphragmatic hernia was created in sheep at 85 days; fetal lungs were collected at 139 days (term = 145 days). Pregnant rats received nitrofen at 12 days; fetal lungs were collected at 21 days (term = 22 days). Some of the sheep fetuses with hernia underwent tracheal occlusion (TO); some of the nitrofen-treated pregnant rats received vitamin A. Both treatments are known to promote lung growth.

MEASUREMENTS AND MAIN RESULTS

Coincidental with the onset of secondary septation, FGF18 protein increased threefold in control human lungs, which failed to occur in CDH. FGF18 labeling was found in interstitial cells of septa. Elastin staining demonstrated poor septation and markedly decreased elastin density in CDH lungs. Consistently, lung FGF18 transcripts were diminished 60 and 83% by CDH in sheep and rats, respectively, and elastin density and expression were diminished. TO and vitamin A restored FGF18 and elastin expression in sheep and rats, respectively. TO restored elastin density.

CONCLUSIONS

Impaired septation in CDH is associated with decreased FGF18 expression and elastic fiber deposition. Simultaneous correction of FGF18 and elastin defects by TO and vitamin A suggests that defective elastogenesis may result, at least partly, from FGF18 deficiency.

The fibroblast growth factor system and mood disorders

Recent evidence now suggests the involvement of the fibroblast growth factor (FGF) system in mood disorders. Specifically, several members of the FGF family have been shown to be dysregulated in individuals with major depression. In this review, we will introduce the FGF system in terms of structure and function during development, in adulthood, and in various regions and cell types. We will also review the FGF system as a mediator of neural plasticity. Furthermore, this review will summarize animal as well as human studies. The majority of animal studies have focused on stress, environmental enrichment, pharmacological manipulations, and the hippocampus. By contrast, human studies have focused on volumetric measurements, antidepressant literature, and, most recently, post-mortem microarray experiments. In summary, a reduced tone in the FGF system might alter brain development or remodeling and result in a predisposition or vulnerability to mood disorders, including major depression.

Schwann cell: A source of neurotrophic activity on cortical glutamatergic neurons in culture

Glial cells secrete numerous soluble molecules that enhance the development and the survival of different neuronal types cultured in vitro. Schwann cells (SC) play an important role as they are the source of different trophic substances and present a great neurotrophic activity. The aim of this study is to investigate the influence of postnatal SC on embryonic glutamatergic neurons. Co-cultures of SC from sciatic nerve of postnatal rats and neurons from rat embryonic cerebral cortex were successfully established, and cells were immunocytochemically characterized using mono and polyclonal antibodies as different glial and neuronal markers. Furthermore, some neuronal cultures were added with Nerve Growth Factor (NGF) and Insulin-like Growth Factor (IGF) to compare to co-cultures. Our results show that SC promote an increase in the number of glutamatergic cortical neurons; moreover, these neurons present an evidence of dense axonal and dendritic outgrowth even when were fed with conditioned medium obtained from SC cultures. In conclusion, our data suggest that substances produced by SC exert a positive effect on central neuron survival and differentiation as indicated by processes of elongation and that this activity is mediated by soluble factors. Therefore, it is possible to consider the SC as a source of growth factors and might be suitable for the development of a neuroprotective effect in neurodegenerative disorders.

Delineation of a 2.2 Mb microdeletion at 5q35 associated with microcephaly and congenital heart disease

Fine mapping of chromosomal deletions and genotype-phenotype comparisons of clinically well-defined patients can be used to confirm or reveal loci and genes associated with human disorders. Eleven patients with cytogenetically visible deletions involving the terminal region of chromosome 5q have been described, but the extent of the deletion was determined only in one case. In this study we describe a 15-year-old boy with Ebstein anomaly, atrial septal defect (ASD), atrioventricular (AV) conduction defect, and microcephaly. He had an apparently balanced paracentric inversion of chromosome 5, with the karyotype 46, XY,inv(5)(q13q35) de novo. Further mapping of the chromosome breakpoints using fluorescence in situ hybridization (FISH) revealed a 2.2 Mb microdeletion at the 5q35 breakpoint, which spans 16 genes, including the cardiac homeobox transcription factor gene NKX2-5. The current data suggest that haploinsufficiency of NKX2-5 cause Ebstein anomaly and support previous results showing that NKX2-5 mutations cause ASD and AV conduction defect. Furthermore, we suggest presence of a new microcephaly locus within a 2.2 Mb region at 5q35.1-q35.2.

Clinical and genetic high-risk strategies in understanding vulnerability to psychosis

Neurodevelopmental processes active during the adolescent period have been hypothesized to participate in the deterioration in functioning associated with the onset of schizophrenia. A number of studies are now underway evaluating individuals in an ultra high-risk clinical state with neuroimaging assessments repeatedly over time, to determine whether particular neural changes predict an imminent onset of psychosis. However, the results of such studies will be difficult to interpret without reference to studies examining the distribution of these neural indicators in the non-clinically-affected first-degree relatives of patients with schizophrenia. Recent work deriving primarily from twin and family studies (i.e., genetic high-risk designs) indicates that some of the alterations in brain function and structure in schizophrenia are primarily genetically mediated and also appear in some of their unaffected first-degree relatives, while other alterations are present in individuals who manifest the illness phenotype but not in relatives at genetic risk. Whereas the primarily genetically mediated deficits shared by at-risk but non-symptomatic relatives are not likely to show differential change in the premorbid period, and may be necessary but clearly not sufficient for the development of psychotic symptoms, the deficits specific to patients who manifest the illness phenotype are good candidates for marking the neurobiological processes associated with the emergence of psychotic symptoms at the time of schizophrenia onset. Preliminary results from longitudinal studies of individuals ascertained initially in a prodromal (i.e., "clinical high-risk") state appear to be interpretable within this framework.

Comprehensive analysis of FGF and FGFR expression in skin: FGF18 is highly expressed in hair follicles and capable of inducing anagen from telogen stage hair follicles

We quantified the mRNA expression of all 22 fibroblast growth factor family members (FGF) and their four receptors (FGFR) in adult mouse full-thickness skin at various stages of the hair growth cycle. We found that in addition to mRNA encoding FGF previously identified in skin (FGF1, 2, 5, 7, 10, 13, and 22), FGF18 mRNA was also strongly expressed. Expression of these FGF varied throughout hair growth cycle: mRNA expression of FGF18 and 13 peaked at telogen; FGF7 and 10 at anagen V; and FGF5 and 22 at anagen VI. In situ hybridization revealed that FGF18 mRNA is mainly expressed in the anagen inner root sheath and telogen bulge of hair follicles. In culture, FGF18 stimulated DNA synthesis in human dermal fibroblasts, dermal papilla cells, epidermal keratinocytes and vascular endothelial cells. When FGF18 was administered subcutaneously to mice in a uniform telogen state, anagen hair growth was observed. Our findings suggest that FGF18 is important for the regulation of hair growth and the maintenance of skin in adult mice.

Fgf18 is required for embryonic lung alveolar development

Fgf18 is abundantly expressed in mouse embryonic lungs. To elucidate the roles of Fgf18 in mouse embryonic lung development, we examined the Fgf18-/- embryonic lungs. Although the sizes of the Fgf18-/- lungs were a little smaller in appearance than those of wild-type lungs, neither proximal nor distal airway branching in the Fgf18-/- lungs was impaired. However, the Fgf18-/- lungs at E18.5 had reduced alveolar space, thicker interstitial mesenchymal compartments, and many embedded capillaries. Cell proliferation in the Fgf18-/- lungs was also transiently reduced around E17.5, although the expression of marker genes for lung epithelial cells in the Fgf18-/- lungs was not impaired. The present findings indicate that the Fgf18 plays roles in lung alveolar development during late embryonic lung development stages. The cell proliferation during the terminal saccular stage stimulated by Fgf18 might play roles in the remodeling of the distal lung.

A survey of the year 2002 commercial optical biosensor literature

We have compiled 819 articles published in the year 2002 that involved commercial optical biosensor technology. The literature demonstrates that the technology's application continues to increase as biosensors are contributing to diverse scientific fields and are used to examine interactions ranging in size from small molecules to whole cells. Also, the variety of available commercial biosensor platforms is increasing and the expertise of users is improving. In this review, we use the literature to focus on the basic types of biosensor experiments, including kinetics, equilibrium analysis, solution competition, active concentration determination and screening. In addition, using examples of particularly well-performed analyses, we illustrate the high information content available in the primary response data and emphasize the impact of including figures in publications to support the results of biosensor analyses.

Biochemical analysis of pathogenic ligand-dependent FGFR2 mutations suggests distinct pathophysiological mechanisms for craniofacial and limb abnormalities

Gain-of-function missense mutations in FGF receptor 2 (FGFR2) are responsible for a variety of craniosynostosis syndromes including Apert syndrome (AS), Pfeiffer syndrome (PS) and Crouzon syndrome (CS). Unlike the majority of FGFR2 mutations, S252W and P253R AS mutations and a D321A PS mutation retain ligand-dependency and are also associated with severe limb pathology. In addition, a recently identified ligand-dependent S252L/A315S double mutation in FGFR2 was shown to cause syndactyly in the absence of craniosynostosis. Here, we analyze the effect of the canonical AS mutations, the D321A PS mutation and the S252L/A315S double mutation on FGFR2 ligand binding affinity and specificity using surface plasmon resonance. Both AS mutations and the D321A PS mutation, but not the S252L/A315S double mutation, increase the binding affinity of FGFR2c to multiple FGFs expressed in the cranial suture. Additionally, all four pathogenic mutations also violate FGFR2c ligand binding specificity and enable this receptor to bind FGF10. Based on our data, we propose that an increase in mutant FGFR2c binding to multiple FGFs results in craniosynostosis, whereas binding of mutant FGFR2c to FGF10 results in severe limb pathology. Structural and biophysical analysis shows that AS mutations in FGFR2b also enhance and violate FGFR2b ligand binding affinity and specificity, respectively. We suggest that elevated AS mutant FGFR2b signaling may account for the dermatological manifestations of AS.

Time window of fibroblast growth factor-18-mediated neuroprotection after occlusion of the middle cerebral artery in rats

To assess the time window for fibroblast growth factor-18 (FGF18)-mediated neuroprotection, FGF18 was administered by intravenous infusion at various times after transient occlusion of the middle cerebral artery (MCAO) in rats. Vehicle or FGF18 (100 microg x kg(-1) x h(-1)) was infused at 0.25, 0.5, 1.0, 2.0, 4.0, or 8.0 hours after MCAO with infarct volumes and behavioral deficits measured at 24.0 hours after MCAO. A separate group of animals received the infusions 24 hours after MCAO with endpoints measured at 48 hours after MCAO. Infusion of FGF18 reduced infarct volumes and improved scores in tests of reference and working memory, motor ability, and exploratory behavior. FGF18 was most efficacious when infused within 2 hours after MCAO. Significant reductions in infarct volumes and reductions in deficits of reference memory and motor activity were also observed with FGF18 infused 24 hours after MCAO. Measurements taken at infusion times before 2 hours after MCAO showed that regional cerebral blood flow was increased by FGF18. Administration of vehicle or FGF18 had no significant effect on mean arterial blood pressure, heart rate, brain temperature, blood pH, Pco2, or Po2. These results demonstrate that FGF18 is an effective neuroprotective agent when administered early after transient MCAO in rats. Efficacy observed with infusions at later times suggests an expanded time window for FGF18-mediated neuroprotection.