Behavioral responses of wild chimpanzees toward a juvenile that suddenly lost its animacy due to a fall accident

Detailed observations of animal reactions to a collapsed individual in wild are rare but essential to debates about the perception of death by nonhuman animals, including chimpanzees. A male juvenile chimpanzee named Volta, a member of the M group in the Mahale Mountains National Park, fell from a tall tree and was temporarily incapacitated, suffering a severe concussion and nasal bone fracture. However, Volta showed signs of gradual recovery. We compared the behavior of other chimpanzees towards Volta with the previous reports on the behavior towards collapsed or recently dead group members. We found that behaviors towards Volta were similar to those observed towards collapsed or dead members. These included other-regarding behaviors and aggressive behaviors, and notably, licking of Volta's blood, which has not been previously reported. Adult males tended to be in close proximity to Volta for longer periods than adult females. The social situation with adult males including alpha male, surrounding Volta likely influenced the behavior of other individuals. Exploring the state of recovery of the injured individual, by closely approaching, directing various behaviors, and observing the reactions of the victim, and demonstrate tolerance and consideration towards the victim.

Metabolic effects of Tofogliflozin are efficiently enhanced with appropriate dietary carbohydrate ratio and are distinct from carbohydrate restriction

Sodium‐glucose cotransporter 2 inhibitors (SGLT2i) exert their antidiabetic effects by promoting urinary glucose excretion. Nutrition therapy is obviously important, but little is known about the interactions between SGLT2i agents and carbohydrate restriction. Therefore, we studied these interactions using an obese diabetic animal model. KK‐A^y mice were pair‐fed normal chow [NC; carbohydrate: fat: protein = 65:15:20], low carbohydrate [LC; 43:42:15] or severely carbohydrate restricted diets [SR; 12:45:43] for 12 weeks. Tofogliflozin (Tofo) was administered as the SGLT2i in the NC and LC diet groups. Blood glucose levels were significantly increased in the SR group. Tofo reduced blood glucose levels significantly in the NC group during the experiment and in the LC group at 2‐6 weeks. Plasma triglycerides were markedly elevated in the SR group without Tofo, but decreased in response to Tofo administration. Hepatic triglyceride contents were not changed by the LC or the SR diet alone. However, Tofo ameliorated hepatosteatosis in NC‐fed animals. Consistent with the downregulation of stearoyl‐CoA desaturase 1, the ratio of plasma monounsaturated to saturated fatty acids was significantly reduced in the LC with Tofo and in the SR alone groups, but was not altered in the NC with Tofo group. In summary, metabolism of glucose and lipids was improved by Tofo but not by the SR diet. Furthermore, Tofo improved these parameters more effectively in the NC than in the LC diet group. These data suggest that the effects of SGLT2i are distinct from those of carbohydrate restriction and that a nonrestricted dietary carbohydrate composition is essential for SGLT2i treatment to be effective.

Influence of long term administration of tofogliflozin on chronic inflammation of visceral adipose tissue in mice with obesity induced by a high-fat diet

We previously found that senescence of cluster of differentiation 4 (CD4) T cells is accelerated in the visceral adipose tissue (VAT) of mice with diet-induced obesity (DIO) due to a high-fat diet (HFD), and that these senescent-associated T cells cause chronic inflammation of visceral adipose tissue through secretion of osteopontin, provoking systemic insulin resistance. In this study, we examined whether the development of chronic inflammation and senescence-associated T cells in VAT of DIO mice was improved by long-term weight loss after switching to normal chow (NC) or by administration of a sodium glucose cotransporter 2 inhibitor (tofogliflozin). Wild-type mice were fed an HFD for 26 weeks from 4 weeks old. At 30 weeks of age, half of these DIO mice were switched to NC with or without 0.005% tofogliflozin for 38 weeks. The other mice remained on the HFD with or without 0.005% tofogliflozin for 38 weeks. When DIO mice were switched to NC, their weight decreased to that of mice kept on NC since weaning. After 38 weeks (68 weeks of age), chronic inflammation of the VAT subsided with disappearance of senescence-associated T cells. In the HFD groups, the carbohydrate intake per mouse was half or less of that in the NC group, and urinary glucose excretion by the effect of tofogliflozin was lower in the HFD mice than in the NC mice. Mice that remained on the HFD showed no improvement in chronic inflammation in VAT, possibly because urinary glucose excretion was not sufficiently promoted by tofogliflozin due to the low carbohydrate intake. Thus, no improvement in glucose metabolism or weight loss was observed in these mice.

Dipeptidyl peptidase 4 inhibitor anagliptin ameliorates hypercholesterolemia in hypercholesterolemic mice through inhibition of intestinal cholesterol transport

Aims/Introduction

Recent data showed that dipeptidyl peptidase 4 (DPP‐4) inhibitors exert a lipid‐lowering effect in diabetes patients. However, the mechanism of action is not yet clearly understood. We investigated the effect of anagliptin on cholesterol metabolism and transport in the small intestine using non‐diabetic hyperlipidemic animals, to clarify the mechanisms underlying the cholesterol‐lowering action.

Materials and Methods

Male apolipoprotein E (ApoE)‐deficient mice were orally administered anagliptin in the normal chow. Serum cholesterol levels and lipoprotein profiles were measured, and cholesterol transport was assessed by measuring the radioactivity in the tissues after oral loading of ¹⁴C‐labeled cholesterol (¹⁴C‐Chol). In additional experiments, effects of exendin‐4 in mice and of anagliptin in DPP‐4‐deficient rats were assessed. Effects on target gene expressions in the intestine were analyzed by quantitative polymerase chain reaction in normal mice.

Results

The serum total and non‐high‐density lipoprotein cholesterol concentrations decreased after anagliptin treatment in the ApoE‐deficient mice. The cholesterol‐lowering effect was predominantly observed in the chylomicron fraction. The plasma ¹⁴C‐Chol radioactivity was significantly decreased by 26% at 2 h after cholesterol loading, and the fecal ¹⁴C‐Chol excretion was significantly increased by 38% at 72 h. The aforementioned effects on cholesterol transport were abrogated in rats lacking DPP‐4 activity, and exendin‐4 had no effect on the ¹⁴C‐Chol transport in ApoE‐deficient mice. Furthermore, significant decreases of the intestinal cholesterol transport‐related microsomal triglyceride transfer protein, acyl‐coenzyme A:cholesterol acyltransferase 2, ApoA2 and ApoC2 messenger ribonucleic acid expressions were observed in the mice treated with repeated doses of anagliptin.

Conclusions

These findings suggest that anagliptin might exert a cholesterol‐lowering action through DPP‐4‐dependent and glucagon‐like peptide 1‐independent suppression of intestinal cholesterol transport.

Cranial shape evolution in adaptive radiations of birds: comparative morphometrics of Darwin's finches and Hawaiian honeycreepers

Adaptive radiation is the rapid evolution of morphologically and ecologically diverse species from a single ancestor. The two classic examples of adaptive radiation are Darwin's finches and the Hawaiian honeycreepers, which evolved remarkable levels of adaptive cranial morphological variation. To gain new insights into the nature of their diversification, we performed comparative three-dimensional geometric morphometric analyses based on X-ray microcomputed tomography (µCT) scanning of dried cranial skeletons. We show that cranial shapes in both Hawaiian honeycreepers and Coerebinae (Darwin's finches and their close relatives) are much more diverse than in their respective outgroups, but Hawaiian honeycreepers as a group display the highest diversity and disparity of all other bird groups studied. We also report a significant contribution of allometry to skull shape variation, and distinct patterns of evolutionary change in skull morphology in the two lineages of songbirds that underwent adaptive radiation on oceanic islands. These findings help to better understand the nature of adaptive radiations in general and provide a foundation for future investigations on the developmental and molecular mechanisms underlying diversification of these morphologically distinguished groups of birds.

This article is part of the themed issue ‘Evo-devo in the genomics era, and the origins of morphological diversity’.

Mechanism of lipid-lowering action of the dipeptidyl peptidase-4 inhibitor, anagliptin, in low-density lipoprotein receptor-deficient mice

Aims/Introduction

Dipeptidyl peptidase‐4 inhibitors are used for treatment of patients with type 2 diabetes. In addition to glycemic control, these agents showed beneficial effects on lipid metabolism in clinical trials. However, the mechanism underlying the lipid‐lowering effect of dipeptidyl peptidase‐4 inhibitors remains unclear. Here, we investigated the lipid‐lowering efficacy of anagliptin in a hyperlipidemic animal model, and examined the mechanism of action.

Materials and Methods

Male low‐density lipoprotein receptor‐deficient mice were administered 0.3% anagliptin in their diet. Plasma lipid levels were assayed and lipoprotein profile was analyzed using high‐performance liquid chromatography. Hepatic gene expression was examined by deoxyribonucleic acid microarray and quantitative polymerase chain reaction analyses. Sterol regulatory element‐binding protein transactivation assay was carried out in vitro.

Results

Anagliptin treatment significantly decreased the plasma total cholesterol (14% reduction, P < 0.01) and triglyceride levels (27% reduction, P < 0.01). Both low‐density lipoprotein cholesterol and very low‐density lipoprotein cholesterol were also decreased significantly by anagliptin treatment. Sterol regulatory element‐binding protein‐2 messenger ribonucleic acid expression level was significantly decreased at night in anagliptin‐treated mice (15% reduction, P < 0.05). Anagliptin significantly suppressed sterol regulatory element‐binding protein activity in HepG2 cells (21% decrease, P < 0.001).

Conclusions

The results presented here showed that the dipeptidyl peptidase‐4 inhibitor, anagliptin, exhibited a lipid‐lowering effect in a hyperlipidemic animal model, and suggested that the downregulation of hepatic lipid synthesis was involved in the effect. Anagliptin might have beneficial effects on lipid metabolism in addition to a glucose‐lowering effect.

Angiopoietin Like Protein 2 (ANGPTL2) Promotes Adipose Tissue Macrophage and T lymphocyte Accumulation and Leads to Insulin Resistance

OBJECTIVES

Angiopoietin-like protein 2 (ANGPTL2), a recently identified pro-inflammatory cytokine, is mainly secreted from the adipose tissue. This study aimed to explore the role of ANGPTL2 in adipose tissue inflammation and macrophage activation in a mouse model of diabetes.

METHODOLOGY/PRINCIPAL FINDINGS

Adenovirus mediated lacZ (Ad-LacZ) or human ANGPTL2 (Ad-ANGPTL2) was delivered via tail vein in diabetic db/db mice. Ad-ANGPTL2 treatment for 2 weeks impaired both glucose tolerance and insulin sensitivity as compared to Ad-LacZ treatment. Ad-ANGPTL2 treatment significantly induced pro-inflammatory gene expression in white adipose tissue. We also isolated stromal vascular fraction from epididymal fat pad and analyzed adipose tissue macrophage and T lymphocyte populations by flow cytometry. Ad-ANGPTL2 treated mice had more adipose tissue macrophages (F4/80+CD11b+) and a larger M1 macrophage subpopulation (F4/80+CD11b+CD11c+). Moreover, Ad-ANGPTL2 treatment increased a CD8-positive T cell population in adipose tissue, which preceded increased macrophage accumulation. Consistent with our in vivo results, recombinant human ANGPTL2 protein treatment increased mRNA levels of pro-inflammatory gene products and production of TNF-α protein in the human macrophage-like cell line THP-1. Furthermore, Ad-ANGPTL2 treatment induced lipid accumulation and increased fatty acid synthesis, lipid metabolism related gene expression in mouse liver.

CONCLUSION

ANGPTL2 treatment promotes macrophage accumulation and activation. These results suggest potential mechanisms for insulin resistance.

Patterns of morphological variation in enamel-dentin junction and outer enamel surface of human molars

Tooth crown patterning is governed by the growth and folding of the inner enamel epithelium (IEE) and the following enamel deposition forms outer enamel surface (OES). We hypothesized that overall dental crown shape and covariation structure are determined by processes that configurate shape at the enamel-dentine junction (EDJ), the developmental vestige of IEE. This this hypothesis was tested by comparing patterns of morphological variation between EDJ and OES in human permanent maxillary first molar (UM1) and deciduous second molar (um2). Using geometric morphometric methods, we described morphological variation and covariation between EDJ and OES, and evaluated the strength of two components of phenotypic variability, canalization and morphological integration, in addition to the relevant evolutionary flexibility, i.e. the ability to respond to selective pressure. The strength of covariation between EDJ and OES was greater in um2 than in UM1, and the way that multiple traits covary between EDJ and OES was different between these teeth. The variability analyses showed that EDJ had less shape variation and a higher level of morphological integration than OES, which indicated that canalization and morphological integration acted as developmental constraints. These tendencies were greater in UM1 than in um2. On the other hand, EDJ and OES had a comparable level of evolvability in these teeth. Amelogenesis could play a significant role in tooth shape and covariation structure, and its influence was not constant among teeth, which may be responsible for the differences in the rate and/or period of enamel formation.

Size and Shape Variability in Human Molars during Odontogenesis

Under the patterning cascade model (PCM) of cusp development inspired by developmental genetic studies, it is predicted that the location and the size of later-forming cusps are more variable than those of earlier-forming ones. Here we assessed whether differences in the variability among cusps in total and each particular crown component (enamel-dentin junction [EDJ], outer enamel surface [OES], and cement-enamel junction [CEJ]) could be explained by the PCM, using human maxillary permanent first molars (UM1) and second deciduous molars (um2). Specimens were µCT-scanned, and 3D models of EDJ and OES were reconstructed. Based on these models, landmark-based 3D geometric morphometric analyses were conducted. Size variability in both tooth types was generally consistent with the above prediction, and the differences in size variation among cusps were smaller for the crown components completed in later stages of odontogenesis. With a few exceptions, however, the prediction was unsupported regarding shape variability, and UM1 and um2 showed different patterns. Our findings suggested that the pattern of size variability would be caused by temporal factors such as the order of cusp initiation and the duration from the beginning of mineralization to the completion of crown formation, whereas shape variability may be affected by both topographic and temporal factors.

Earliest colobine skeletons from Nakali, Kenya

Old World monkeys represent one of the most successful adaptive radiations of modern primates, but a sparse fossil record has limited our knowledge about the early evolution of this clade. We report the discovery of two partial skeletons of an early colobine monkey (Microcolobus) from the Nakali Formation (9.8-9.9 Ma) in Kenya that share postcranial synapomorphies with extant colobines in relation to arboreality such as mediolaterally wide distal humeral joint, globular humeral capitulum, distinctly angled zona conoidea, reduced medial trochlear keel, long medial epicondyle with weak retroflexion, narrow and tall olecranon, posteriorly dislocated fovea on the radial head, low projection of the femoral greater trochanter, wide talar head with a greater rotation, and proximodistally short cuboid and ectocuneiform. Microcolobus in Nakali clearly differs from the stem cercopithecoid Victoriapithecus regarding these features, as Victoriapithecus is postcranially similar to extant small-sized terrestrial cercopithecines. However, degeneration of the thumb, a hallmark of modern colobines, is not observed, suggesting that this was a late event in colobine evolution. This discovery contradicts the prevailing hypothesis that the forest invasion by cercopithecids first occurred in the Plio-Pleistocene, and shows that this event occurred by the late Miocene at a time when ape diversity declined.

Prenatal ontogeny of subspecific variation in the craniofacial morphology of the Japanese macaque (Macaca fuscata)

We cross-sectionally investigated prenatal ontogeny of craniofacial shape in the two subspecies of the Japanese macaque (Macaca fuscata fuscata and Macaca fuscata yakui) using a geometric morphometric technique to explore the process of morphogenetic divergence leading to the adult morphological difference between the subspecies. The sample comprised a total of 32 formalin-fixed fetal specimens of the two subspecies, in approximately the second and third trimesters. Each fetal cranium was scanned using computed tomography to generate a three-dimensional surface model, and 68 landmarks were digitized on the external and internal surface of each cranium to trace the growth-related changes in craniofacial shape of the two subspecies. The results of our study demonstrated that the two subspecies generally shared the same craniofacial growth pattern. Both crania tend to exhibit relative contraction of the neurocranium in the mediolateral and superoinferior directions, a more superiorly positioned cranial base, a more vertically oriented occipital squama, and a more anteriorly positioned viscerocranium as the cranial size increased. However, distinctive subspecific differences, for example relatively narrower orbital breadth, higher orbit, higher position of the nuchal crest, and more protrudent snout found in Macaca fuscata yakui were already present during the prenatal period. This study demonstrated that morphological differentiation in the craniofacial shape may occur at a very early stage of the fetal period even between closely related subspecies of the Japanese macaque.

Molecular mechanism of moderate insulin resistance in adiponectin-knockout mice

Adiponectin has been proposed to act as an antidiabetic adipokine, suppressing gluconeogenesis and stimulating fatty acid oxidation in the liver and skeletal muscle. Although adiponectin-knockout (adipo(-/-)) mice are known to exhibit insulin resistance, the degrees of insulin resistance and glucose intolerance are unexpectedly only moderate. In this study, the adipo(-/-) mice showed hepatic, but not muscle, insulin resistance. insulin-stimulated phosphorylation of IRS-1 and IRS-2 was impaired, the IRS-2 protein level was decreased, and insulin-stimulated phosphorylation of Akt was decreased in the liver of the adipo(-/-) mice. However, the triglyceride content in the liver was not increased in these mice, despite the decrease in the PPARalpha expression involved in lipid combustion, since the expressions of lipogenic genes such as SREBP-1 and SCD-1 were decreased in association with the increased leptin sensitivity. Consistent with this, the down-regulation SREBP-1 and SCD-1 observed in the adipo(-/-) mice was no longer observed, and the hepatic triglyceride content was significantly increased in the adiponectin leptin double-knockout (adipo(-/-)ob/ob) mice. On the other hand, the triglyceride content in the skeletal muscle was significantly decreased in the adipo(-/-) mice, probably due to up-regulated AMPK activity associated with the increased leptin sensitivity. In fact, these phenotypes in the skeletal muscle of these mice were no longer observed in the adipo(-/-)ob/ob mice. In conclusion, adipo(-/-) mice showed impaired insulin signaling in the liver to cause hepatic insulin resistance, however, no increase in the triglyceride content was observed in either the liver or the skeletal muscle, presumably on account of the increased leptin sensitivity.

Adiponectin stimulates AMP-activated protein kinase in the hypothalamus and increases food intake

Adiponectin has been shown to stimulate fatty acid oxidation and enhance insulin sensitivity through the activation of AMP-activated protein kinase (AMPK) in the peripheral tissues. The effects of adiponectin in the central nervous system, however, are still poorly understood. Here, we show that adiponectin enhances AMPK activity in the arcuate hypothalamus (ARH) via its receptor AdipoR1 to stimulate food intake; this stimulation of food intake by adiponectin was attenuated by dominant-negative AMPK expression in the ARH. Moreover, adiponectin also decreased energy expenditure. Adiponectin-deficient mice showed decreased AMPK phosphorylation in the ARH, decreased food intake, and increased energy expenditure, exhibiting resistance to high-fat-diet-induced obesity. Serum and cerebrospinal fluid levels of adiponectin and expression of AdipoR1 in the ARH were increased during fasting and decreased after refeeding. We conclude that adiponectin stimulates food intake and decreases energy expenditure during fasting through its effects in the central nervous system.

Promotion of corneal epithelial wound healing in vitro and in vivo by annexin A5

PURPOSE

To investigate the effect of annexin A5, a calcium-dependent phospholipid-binding protein, on corneal epithelial wound healing.

METHODS

The effect of annexin A5 on migration of rabbit corneal epithelial (RCE) cells in vitro was examined in scrape-wounded cell monolayers. The effect of annexin A5 on the release of urokinase-type plasminogen activator (uPA) from cultured RCE cells was determined by zymography, fluorogenic assay of PA activity, and enzyme-linked immunosorbent assay. The proliferation of RCE cells was assessed by measurement of [3H]thymidine incorporation. The effect of annexin A5 on corneal wound closure in rabbits was investigated after removal of the corneal epithelium, either by exposure to iodine vapor or surgically. Eye drops containing annexin A5 were instilled into one eye and vehicle into the other. The area of the epithelial defect was measured at various times after wounding, and the healing rate was calculated by linear regression analysis.

RESULTS

Annexin A5 significantly promoted the migration of RCE cells in a wounded monolayer. However, annexin A5 had no effect on RCE cell proliferation. Annexin A5 also increased the release of uPA both from wounded RCE cell monolayers and from nonwounded semiconfluent RCE cells. In both models of corneal wound closure, the healing rate was significantly increased by instillation of eye drops containing annexin A5 compared with that apparent in the eyes that received vehicle.

CONCLUSIONS

Annexin A5 promoted corneal epithelial wound healing both in vitro and in vivo. Upregulation of uPA release from corneal epithelial cells may contribute to this effect of annexin A5.

Pioglitazone Ameliorates Insulin Resistance and Diabetes by Both Adiponectin-dependent and -independent Pathways

Thiazolidinediones have been shown to up-regulate adiponectin expression in white adipose tissue and plasma adiponectin levels, and these up-regulations have been proposed to be a major mechanism of the thiazolidinedione-induced amelioration of insulin resistance linked to obesity. To test this hypothesis, we generated adiponectin knock-out (adipo-/-) ob/ob mice with a C57B/6 background. After 14 days of 10 mg/kg pioglitazone, the insulin resistance and diabetes of ob/ob mice were significantly improved in association with significant up-regulation of serum adiponectin levels. Amelioration of insulin resistance in ob/ob mice was attributed to decreased glucose production and increased AMP-activated protein kinase in the liver but not to increased glucose uptake in skeletal muscle. In contrast, insulin resistance and diabetes were not improved in adipo-/-ob/ob mice. After 14 days of 30 mg/kg pioglitazone, insulin resistance and diabetes of ob/ob mice were again significantly ameliorated, which was attributed not only to decreased glucose production in the liver but also to increased glucose uptake in skeletal muscle. Interestingly, adipo-/-ob/ob mice also displayed significant amelioration of insulin resistance and diabetes, which was attributed to increased glucose uptake in skeletal muscle but not to decreased glucose production in the liver. The serum-free fatty acid and triglyceride levels as well as adipocyte sizes in ob/ob and adipo-/-ob/ob mice were unchanged after 10 mg/kg pioglitazone but were significantly reduced to a similar degree after 30 mg/kg pioglitazone. Moreover, the expressions of TNFalpha and resistin in adipose tissues of ob/ob and adipo-/-ob/ob mice were unchanged after 10 mg/kg pioglitazone but were decreased after 30 mg/kg pioglitazone. Thus, pioglitazone-induced amelioration of insulin resistance and diabetes may occur adiponectin dependently in the liver and adiponectin independently in skeletal muscle.

Insulin receptor substrate 2 plays a crucial role in beta cells and the hypothalamus

We previously demonstrated that insulin receptor substrate 2 (Irs2) KO mice develop diabetes associated with hepatic insulin resistance, lack of compensatory beta cell hyperplasia, and leptin resistance. To more precisely determine the roles of Irs2 in beta cells and the hypothalamus, we generated beta cell-specific Irs2 KO and hypothalamus-specific Irs2 knockdown (betaHT-IRS2) mice. Expression of Irs2 mRNA was reduced by approximately 90% in pancreatic islets and was markedly reduced in the arcuate nucleus of the hypothalamus. By contrast, Irs2 expression in liver, muscle, and adipose tissue of betaHT-IRS2 mice was indistinguishable from that of control mice. The betaHT-IRS2 mice displayed obesity and leptin resistance. At 4 weeks of age, the betaHT-IRS2 mice showed normal insulin sensitivity, but at 8 and 12 weeks, they were insulin resistant with progressive obesity. Despite their normal insulin sensitivity at 8 weeks with caloric restriction, the betaHT-IRS2 mice exhibited glucose intolerance and impaired glucose-induced insulin secretion. beta Cell mass and beta cell proliferation in the betaHT-IRS2 mice were reduced significantly at 8 and 12 weeks but not at 10 days. Insulin secretion, normalized by cell number per islet, was significantly increased at high glucose concentrations in the betaHT-IRS2 mice. We conclude that, in beta cells and the hypothalamus, Irs2 is crucially involved in the regulation of beta cell mass and leptin sensitivity.

Up-regulation of urokinase-type plasminogen activator in corneal epithelial cells induced by wounding

PURPOSE

To investigate the possible role of urokinase-type plasminogen activator (uPA) in corneal epithelial wound healing by examining its expression both in the rabbit corneal epithelium in situ and in rabbit corneal epithelial (RCE) cells in vitro.

METHODS

The rabbit cornea was subjected to mechanical wounding, and frozen sections of the tissue were subsequently prepared and subjected both to immunostaining with antibodies to uPA and to in situ zymography for the detection of PA activity. RCE cell monolayers were also subjected to scrape wounding, after which they were immunostained for uPA. The amounts of uPA protein in the culture medium and of uPA mRNA in cell lysates were also determined by enzyme-linked immunosorbent assay and by reverse transcription and real-time quantitative polymerase chain reaction analysis, respectively.

RESULTS

Immunostaining and in situ zymography of the wounded cornea revealed that uPA was restricted to the leading edge of the migrating corneal epithelium. In contrast, tissue-type PA was expressed throughout the corneal epithelium. Scraping of RCE cell monolayers induced the expression of uPA in the migrating cells at the wound edge. The amount of uPA in the culture medium of RCE cells increased with the number of scrape wounds applied. Wounding also induced a time-dependent increase in the abundance of uPA mRNA in the cell monolayers. The migration of RCE cells was inhibited by antibodies to uPA.

CONCLUSIONS

Mechanical wounding induces up-regulation of uPA at both the protein and mRNA levels in corneal epithelial cells. uPA may thus contribute to epithelial cell migration during corneal epithelial wound healing.

Disruption of adiponectin causes insulin resistance and neointimal formation

The adipocyte-derived hormone adiponectin has been proposed to play important roles in the regulation of energy homeostasis and insulin sensitivity, and it has been reported to exhibit putative antiatherogenic properties in vitro. In this study we generated adiponectin-deficient mice to directly investigate whether adiponectin has a physiological protective role against diabetes and atherosclerosis in vivo. Heterozygous adiponectin-deficient (adipo(+/-)) mice showed mild insulin resistance, while homozygous adiponectin-deficient (adipo(-/-)) mice showed moderate insulin resistance with glucose intolerance despite body weight gain similar to that of wild-type mice. Moreover, adipo(-/-) mice showed 2-fold more neointimal formation in response to external vascular cuff injury than wild-type mice (p = 0.01). This study provides the first direct evidence that adiponectin plays a protective role against insulin resistance and atherosclerosis in vivo.