Exploring Pleiotropic Functions of Canine ß-Defensin 103: Nasal Cavity Expression, Antimicrobial Activity, and Melanocortin Receptor Activity.

Canine ß-defensin 103 (cBD103) and its common variant cBD103ΔG23 are multitasking polypeptides. As a ß-defensin, cBD103 is one of many antimicrobial agents used by the innate immunity to thwart pathogenic colonization. In this study, we showed that cBD103 was expressed throughout the nasal cavity, with primary expression in the nares as well as respiratory and olfactory epithelia. In the rostral nasal concha, cBD103 was expressed in the epithelium, and to a lesser degree in the lamina propria, but was absent in goblet cells. In the main olfactory epithelium, virtually all cells in the epithelial layer and select cells associated with Bowman's glands expressed cBD103. We also showed that the ΔG23 mutation did not appreciably alter the antimicrobial activity of the peptide against several species of microorganisms tested in nutrient-rich or minimal media or minimal media with salt added. Moreover, we showed antimicrobial activity in minimal media did not necessarily predict the inhibitory action of the peptide in nutrient-rich media. Both forms of cBD103 caused ultrastructural changes (membrane blebbing, condensation of intracellular contents and cell wall lysis) in Escherichia coli and Staphylococcus aureus. As a ligand of the melanocortin receptors, we showed that cBD103ΔG23 increased ERK1/2 activation and cAMP accumulation when bound to the human or canine melanocortin-4 receptor, acting as a weak allosteric agonist.

Is the Mole Rat Vomeronasal Organ Functional?

The colonial naked mole rat Heterocephalus glaber is a subterranean, eusocial rodent. The H. glaber vomeronasal organ neuroepithelium (VNE) displays little postnatal growth. However, the VNE remains neuronal in contrast to some mammals that possess nonfunctional vomeronasal organ remnants, for example, catarrhine primates and some bats. Here, we describe the vomeronasal organ (VNO) microanatomy in the naked mole rat and we make preliminary observations to determine if H. glaber shares its minimal postnatal VNE growth with other African mole rats. We also determine the immunoreactivity to the mitotic marker Ki67, growth-associated protein 43 (GAP43), and olfactory marker protein (OMP) in six adult and three subadult H. glaber individuals. VNE volume measurements on a small sample of Cryptomys hottentotus and Fukomys damarensis indicate that the VNE of those African mole rat species are also likely to be growth-deficient. Ki67(+) cells show that the sensory epithelium is mitotically active. GAP43 labelling indicates neurogenesis and OMP(+) cells are present though less numerous compared to GAP43(+) cells. In this respect, the VNO of H. glaber does not appear vestigial. The African mole rat VNE may be unusually variable, perhaps reflecting reduced selection pressure on the vomeronasal system. If so, African mole rats may provide a useful genetic model for understanding the morphological variability observed in the mammalian VNO. Anat Rec, 2019. © 2019 Wiley Periodicals, Inc. Anat Rec, 303:318-329, 2020. © 2019 American Association for Anatomy.

The Combination of Omega-3 Stearidonic Acid and Docetaxel Enhances Cell Death over Docetaxel Alone in Human Prostate Cancer Cells.

Background: Docetaxel (DOC), or Taxotere, is an anthracycline antibiotic used to treat multiple types of cancer. It is a first-line chemotherapy treatment for patients with metastasized, hormone-resistant prostate cancer (PCa) or for patients with high-risk, localized PCa that could benefit from early chemotherapy treatment. Previously, we showed that stearidonic acid (SDA), an omega-3 fatty acid, enhances the cytotoxicity of doxorubicin (DOX) in human PCa cells. This observation suggests that PCa therapies using SDA and chemotherapeutic drugs in combination offer attractive possibilities for developing treatments that ameliorate toxic side effects of some commonly used chemotherapy drugs. Objectives: We used androgen-resistant PC3 and DU 145 cells derived from human prostate cancer to quantify the effects of combined SDA and DOC on proliferation/viability and on the production of pro-apoptotic caspases 9 and 3. We also compared the effects of SDA with those of BAY, a pharmacological inhibitor of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ĸB), in androgen-sensitive LNCaP cells. Finally, we qualitatively and quantitatively assessed the drug combination on androgen receptor (AR) and peroxisome proliferator-activated receptor gamma (PPARγ) expression in LNCaP and PC3 cells, respectively. Methods: The half maximal inhibitory concentration (IC50) and combination indices of SDA and DOC in PC3 and DU 145 cells were determined using the MTT cell viability assay. To quantify the effects of SDA and BAY on NF-ĸB activity, we used luciferase reporter assays in LNCaP cells that were stably transduced with lentiviral vectors carrying NF-ĸB response element sequence upstream of the luciferase gene sequence. AR and PPARγ expression were assessed by western blotting and immunocytochemistry. We considered caspase 9 and 3 cleavage to be apoptosis markers and determined the drug combination effect on the extent of that cleavage by western blot analysis. Results: The cytotoxic effects of DOC were synergistically enhanced by SDA when the two were added to DU145 and PC3 cell cultures. Combination index (CI) analyses based on the Chou-Talalay method and mass action law showed synergistic interaction with CI <1. SDA suppressed TNFα-induced NF-κB activity similarly to BAY. The SDA/DOC combination down regulated testosterone (T)-induced AR and troglitazone-induced PPARγ protein expression when compared to using the drugs singly. Similarly, the SDA/DOC combination induced caspase 9 and 3 production and cleavage suggesting apoptosis induction. Like our DOX studies, this work provides proof-of-concept for using SDA and DOC in combination to reduce the dose, and therefore the toxicity, of DOC and possibly increasing the survival benefit in DOC clinical translation studies.

Regulation of intracellular trafficking and secretion of adiponectin by myosin II.

Adiponectin is a protein secreted by white adipocytes that plays an important role in insulin action, energy homeostasis and the development of atherosclerosis. The intracellular localization and trafficking of GLUT4 and leptin in adipocytes has been well studied, but little is known regarding the intracellular trafficking of adiponectin. Recent studies have demonstrated that constitutive adiponectin secretion is dependent on PIP2 levels and the integrity of cortical F-actin. Non-muscle myosin II is an actin-based motor that is associated with membrane vesicles and participates in vesicular trafficking in mammalian cells. Therefore, we investigated the role of myosin II in the trafficking and secretion of adiponectin in 3T3-L1 adipocytes. Confocal microscopy revealed that myosin IIA and IIB were dispersed throughout the cytoplasm of the adipocyte. Both myosin isoforms were localized in the Golgi/TGN region as evidenced by colocalization with the cis-Golgi marker, p115 and the trans-Golgi marker, γ-adaptin. Inhibition of myosin II activity by blebbistatin or actin depolymerization by latrunculin B dispersed myosin IIA and IIB towards the periphery while significantly inhibiting adiponectin secretion. Therefore, the constitutive trafficking and secretion of adiponectin in 3T3-L1 adipocytes occurs by an actin-dependent mechanism that involves the actin-based motors, myosin IIA and IIB.

AAV-mediated gene delivery attenuates neuroinflammation in feline Sandhoff disease.

Sandhoff disease (SD) is a lysosomal storage disorder characterized by the absence of hydrolytic enzyme ß-N-acetylhexosaminidase (Hex), which results in storage of GM2 ganglioside in neurons and unremitting neurodegeneration. Neuron loss initially affects fine motor skills, but rapidly progresses to loss of all body faculties, a vegetative state, and death by five years of age in humans. A well-established feline model of SD allows characterization of the disease in a large animal model and provides a means to test the safety and efficacy of therapeutic interventions before initiating clinical trials. In this study, we demonstrate a robust central nervous system (CNS) inflammatory response in feline SD, primarily marked by expansion and activation of the microglial cell population. Quantification of major histocompatibility complex II (MHC-II) labeling revealed significant up-regulation throughout the CNS with areas rich in white matter most severely affected. Expression of the leukocyte chemokine macrophage inflammatory protein-1 alpha (MIP-1α) was also up-regulated in the brain. SD cats were treated with intracranial delivery of adeno-associated viral (AAV) vectors expressing feline Hex, with a study endpoint 16weeks post treatment. AAV-mediated gene delivery repressed the expansion and activation of microglia and normalized MHC-II and MIP-1α levels. These data reiterate the profound inflammatory response in SD and show that neuroinflammation is abrogated after AAV-mediated restoration of enzymatic activity.

The vomeronasal complex of nocturnal strepsirhines and implications for the ancestral condition in primates.

This study investigates the vomeronasal organ in extant nocturnal strepsirhines as a model for ancestral primates. Cadaveric samples from 10 strepsirhine species, ranging from fetal to adult ages, were studied histologically. Dimensions of structures in the vomeronasal complex, such as the vomeronasal neuroepithelium (VNNE) and vomeronasal cartilage (VNC) were measured in serial sections and selected specimens were studied immunohistochemically to determine physiological aspects of the vomeronasal sensory neurons (VSNs). Osteological features corresponding to vomeronasal structures were studied histologically and related to 3-D CT reconstructions. The VNC consistently rests in a depression on the palatal portion of the maxilla, which we refer to as the vomeronasal groove (VNG). Most age comparisons indicate that in adults VNNE is about twice the length compared with perinatal animals. In VNNE volume, adults are 2- to 3-fold larger compared with perinatal specimens. Across ages, a strong linear relationship exists between VNNE dimensions and body length, mass, and midfacial length. Results indicate that the VNNE of nocturnal strepsirhines is neurogenic postnatally based on GAP43 expression. In addition, based on Olfactory Marker Protein expression, terminally differentiated VSNs are present in the VNNE. Therefore, nocturnal strepsirhines have basic similarities to rodents in growth and maturational characteristics of VSNs. These results indicate that a functional vomeronasal system is likely present in all nocturnal strepsirhines. Finally, given that osteological features such as the VNG are visible on midfacial bones, primate fossils can be assessed to determine whether primate ancestors possessed a vomeronasal complex morphologically similar to that of modern nocturnal strepsirhines.

Dental topographic analysis of the molar teeth of primates.

The study of tooth form is informative about the relationship between teeth and the material properties of foods consumed. Studies of dental functional morphology depend on precise characterization of relevant aspects of crown form; the occlusal surfaces of primate molar teeth are studied in 3-dimensional space more and more commonly today. Dental topographic analysis is becoming an increasingly popular method for studying tooth form, given its ability to characterize functionally relevant aspects of tooth form from an entire occlusal surface. This landmark-free approach has been especially valuable in studies of the effects of tooth wear on shape. Mean slope and relief, for example, have been found to be informative about the function of molar teeth in both living and extinct primates. Instructions for the use of this approach are provided here.

Expression of melanocortin receptors in human prostate cancer cell lines: MC2R activation by ACTH increases prostate cancer cell proliferation.

The melanocortin receptors (MCRs 1-5) are G protein coupled-receptors (GPCRs) that regulate food intake, inflammation, skin pigmentation, sexual function and steroidogenesis. Their peptide ligands, the melanocortins, are α-, ß- and γ-melanocyte-stimulating hormone and adrenocorticotropic hormone (ACTH) all of which are secreted from the anterior pituitary gland under hypothalamic control. MC2R binds ACTH but has no affinity for the other melanocortins and is, thereby, pharmacologically different from MCRs that bind those ligands. Evidence suggests that elevated GPCRs transactivate the androgen receptor (AR), the critical mediator of prostate cell growth, and consequently promote prostate cancer cell proliferation. It may be that reduced central melanocortin signaling is coincidental with reversal of prostate cancer cachexia, but no data are available on the expression of, or the role for, MCRs in prostate cancer. Here, we show that MCR (1-5) mRNAs are expressed in androgen-dependent LNCaP and androgen-independent PC3 and DU-145 human prostate cancer cell lines. Further, MC2R, the specific target of ACTH, is expressed in LNCaP, PC3 and DU-145 cells. Among the several synthetic MCR peptide ligands that we used, only ACTH promoted concentration-dependent cell proliferation in the three cell lines as shown by MTT cell proliferation assay. In LNCaP cells, the effect was additive with testosterone stimulation and was partially blunted with SHU9119, a non-selective MCR antagonist. In the same cells, ACTH induced cAMP production and increased AR nuclear labeling in immunocytochemical assays. Our observations suggest that MC2R is involved in prostate carcinogenesis and that targeting MC2R signaling may provide a novel avenue in prostate carcinoma treatment.

Olfactory responses to explosives associated odorants are enhanced by zinc nanoparticles.

Many odorants related to manufactured explosives have low volatilities and are barely detectable as odors. We previously reported that zinc metal nanoparticles increased rat olfactory epithelium responses, measured by electroolfactogram (EOG), to several odorants. Here, we report that nanomolar concentrations of zinc metal nanoparticles strongly enhanced olfactory responses to the explosives related odorants cyclohexanone, methyl benzoate, acetophenone, and eugenol. Rat olfactory epithelium was exposed to metal nanoparticles and odorant responses were quantified by EOG. Zinc nanoparticles added to explosive odorants strongly increased the odorant response in a dose-dependent manner. The enzymatic breakdown of the second messenger cyclic adenosine monophosphate (cAMP) was prevented by adding the membrane-permeable phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX). This caused the olfactory cilia cAMP concentration to increase and generated EOG signals. The EOG responses generated by IBMX were not enhanced by zinc nanoparticles. Based on these observations, we conclude that zinc nanoparticles act at the receptor site and are involved in the initial events of olfaction. Our results suggest that zinc metal nanoparticles can be used to facilitate a canine detection of explosive odorants.

The vomeronasal organ of New World monkeys (platyrrhini).

Although all platyrrhine primates possess a vomeronasal organ (VNO), few species have been studied in detail. Here, we revisit the microanatomy of the VNO and related features in serially sectioned samples from 41 platyrrhine cadavers (14 species) of mixed age. Procedures to identify terminally differentiated vomeronasal sensory neurons (VSNs) via immunolabeling of olfactory marker protein (OMP) were used on selected specimens. The VNO varies from an elongated epithelial tube (e.g., Ateles fusciceps) to a dorsoventrally expanded sac (e.g., Saguinus spp.). The cartilage that surrounds the VNO is J-shaped or U-shaped in most species, and articulates with a groove on the bony palate. Preliminary results indicate a significant correlation between the length of this groove and length of the VNO neuroepithelium, indicating this feature may serve as a skeletal correlate. The VNO neuroepithelium could be identified in all adult primates except Alouatta, in which poor preservation prevented determination. The VNO of Ateles, described in detail for the first time, had several rows of VSNs and nerves in the surrounding lamina propria. Patterns of OMP-reactivity in the VNO of perinatal platyrrhines indicate that few or no terminally differentiated VSNs are present at birth, thus supporting the hypothesis that some platyrrhines may have delayed maturation of the VNO. From a functional perspective, all platyrrhines studied possess structures required for chemoreception (VSNs, vomeronasal nerves). However, some microanatomical findings, such as limited reactivity to OMP in some species, indicate that some lineages of New World monkeys may have a reduced or vestigial vomeronasal system.

Olfactory marker protein expression in the vomeronasal neuroepithelium of tamarins (Saguinus spp).

Knowledge of the vomeronasal neuroepithelium (VNNE) microanatomy is disproportionately based on rodents. To broaden our knowledge, we examined olfactory marker protein (OMP) expression in a sample of twenty-three non-human primates. The density of OMP (+) vomeronasal sensory neurons (VSNs) in the VNNE was measured. Here we compared OMP (+) VSN density in five species of Saguinus (a genus of New World monkey) of different ages to a comparative primate sample that included representatives of every superfamily in which a VNO is postnatally present. In Saguinus spp., the VNNE at birth is thin, usually comprising one or two nuclear rows. At all ages studied, few VNNE cells are OMP reactive as view in coronal sections. In the comparative sample, the OMP (+) VSNs appear to be far more numerous in the spider monkey (another New World monkey) and the bushbaby (a distant relative). Other species (e.g., owl monkey) had a similar low density of OMP (+) VSNs as in Saguinus. These results expand our earlier finding that few VSNs are OMP (+) in Saguinus geoffroyi to other species of the genus. Our sample indicates that the number of OMP (+) VSNs in primates varies from ubiquitous to few with New World monkeys varying the most. The scarcity of OMP (+) cells in some primate VNOs reflects a lower number of terminally differentiated VSNs compared to a diverse range of mammals. If primates with relatively few OMP (+) VSNs have a functional vomeronasal system, OMP is not critical for stimulus detection.

Odorant response kinetics from cultured mouse olfactory epithelium at different ages in vitro.

Mammalian olfactory epithelium can withstand the external environment, undergo life-long regeneration, and respond to thousands of odorant stimuli, making it an attractive system for a variety of studies. Previously, we described a long-lived olfactory coculture of olfactory epithelium and bulb tissues and we present here the kinetic properties of that culture system. Neonatal mouse epithelial-bulbar explants were grown for periods as long as 121 days in vitro (DIV), nearly doubling the survival time of our previously longest lived cultures. Cultures at all ages responded to air-borne odorants. The youngest cultures (1-15 DIV) showed shorter half-rise and half-decay times than older cultures (21-121 DIV), and were more variable in their half-decay times. Zinc nanoparticles enhanced electro-olfactogram responses of both younger and older cultures and both groups were immunopositive for olfactory marker protein. The results show that our olfactory culture model can support mature, odorant-responsive olfactory receptor neurons that possess many of the response features of in situ olfactory receptor neurons.

Insulin treatment prevents diabetes-induced alterations in astrocyte glutamate uptake and GFAP content in rats at 4 and 8 weeks of diabetes duration.

Rat astrocyte function is changed by diabetes mellitus relative to the nondiabetic state and we believe that altered function contributes to the central nervous system symptoms manifested by individuals with diabetes. We report here a comparison of astrocyte glutamate uptake and GFAP expression in streptozotocin-induced type 1 diabetic rats and insulin-treated diabetic rats at 4 and 8 weeks following diabetes onset. In glial plasmalemmal vesicle (GPV) preparations from treated rats, insulin prevented the increase observed in untreated, diabetic rats of both sodium-dependent and sodium-independent glutamate uptake. We determined by immunoblotting and immunohistochemistry that insulin treatment prevented the decrease of GFAP expression detected in the cerebral cortex, hippocampus, and cerebellum of untreated, diabetic rats. These observations indicate that insulin effects on astrocyte function are significant in managing diabetes-induced central nervous system pathology.

Enhancement of odorant-induced responses in olfactory receptor neurons by zinc nanoparticles.

Zinc metal nanoparticles in picomolar concentrations strongly enhance odorant responses of olfactory sensory neurons. One- to 2-nm metallic particles contain 40-300 zinc metal atoms, which are not in an ionic state. We exposed rat olfactory epithelium to metal nanoparticles and measured odorant responses by electroolfactogram and whole-cell patch clamp. A small amount of zinc nanoparticles added to an odorant or an extracellular/intracellular particle perfusion strongly increases the odorant response in a dose-dependent manner. Zinc nanoparticles alone produce no odor effects. Copper, gold, or silver nanoparticles do not produce effects similar to those of zinc. If zinc nanoparticles are replaced by Zn(+2) ions in the same concentration range, we observed a reduction of the olfactory receptor neuron odorant response. Based on these observations, we hypothesize that zinc nanoparticles are closely located to the interface between the guanine nucleotide-binding protein and the receptor proteins and are involved in transferring signals in the initial events of olfaction. Our results suggest that zinc metal nanoparticles can be used to enhance and sustain the initial olfactory events.

Bovine viral diarrhea virus is a suitable viral vector for stable expression of heterologous gene when inserted in between N(pro) and C genes.

Bovine viral diarrhea virus (BVDV) is a group of small enveloped viruses with a single-stranded, positive-oriented RNA genome of approximately 12.3 kb. BVDV genome directs the production of a viral polyprotein that is subsequently cleaved to release the mature viral proteins. To explore the potential of using BVDV as viral vector for stable expression of heterologous genes, eGFP2A was inserted in between N(pro) and C genes of a noncytopathic type-I BVDV strain SD1. eGFP2A was designed with eGFP protein in frame fused to the N terminus of the foot-and-mouth disease virus 2A protease. This strategy promised not only the correct processing of both viral N(pro) and C protein but also releasing of the chimeric protein from the nascent viral polyprotein. The recombinant reporter virus was successfully rescued in MDBK cells. In vitro study showed that eGFP2A protein, as expected, was expressed and processed properly from the nascent viral polyprotein. The reporter virus was similar to wt SD1 in viral RNA replication and protein expression and comparable to wt SD1 in growth kinetics except that this virus had a peak virus titer approximately 0.5 log(10) lower and a maximum yield about 4h later than wt SD1. In summary, these results indicated that BVDV is a suitable viral vector for stable expression of heterologous genes when inserted in between N(pro) and C genes.

Activation of Penile Proadipogenic Peroxisome Proliferator-Activated Receptor gamma with an Estrogen: Interaction with Estrogen Receptor Alpha during Postnatal Development.

Exposure to the estrogen receptor alpha (ERalpha) ligand diethylstilbesterol (DES) between neonatal days 2 to 12 induces penile adipogenesis and adult infertility in rats. The objective of this study was to investigate the in vivo interaction between DES-activated ERalpha and the proadipogenic transcription factor peroxisome proliferator-activated receptor gamma (PPARgamma). Transcripts for PPARs alpha, beta, and gamma and gamma1a splice variant were detected in Sprague-Dawley normal rat penis with PPARgamma predominating. In addition, PPARgamma1b and PPARgamma2 were newly induced by DES. The PPARgamma transcripts were significantly upregulated with DES and reduced by antiestrogen ICI 182, 780. At the cellular level, PPARgamma protein was detected in urethral transitional epithelium and stromal, endothelial, neuronal, and smooth muscular cells. Treatment with DES activated ERalpha and induced adipocyte differentiation in corpus cavernosum penis. Those adipocytes exhibited strong nuclear PPARgamma expression. These results suggest a biological overlap between PPARgamma and ERalpha and highlight a mechanism for endocrine disruption.

Temporal delay of peak T-cell immunity determines Chlamydia pneumoniae pulmonary disease in mice.

Severe chlamydial disease typically occurs after previous infections and results from a hypersensitivity response that is also required for chlamydial elimination. Here, we quantitatively dissected the immune and disease responses to repeated Chlamydia pneumoniae lung infection by multivariate modeling with four dichotomous effects: mouse strain (A/J or C57BL/6), dietary protein content (14% protein and 0.3% L-cysteine-0.9% L-arginine, or 24% protein and 0.5% L-cysteine-2.0% L-arginine), dietary antioxidant content (90 IU alpha-tocopherol/kg body weight versus 450 IU alpha-tocopherol/kg and 0.1% g L-ascorbate), and time course (3 or 10 days postinfection). Following intranasal C. pneumoniae challenge, C57BL/6 mice on a low-protein/low-antioxidant diet, but not C57BL/6 mice on other diets or A/J mice, exhibited profoundly suppressed early lung inflammatory and pan-T-cell (CD3delta(+)) and helper T-cell (CD45) responses on day 3 but later strongly exacerbated disease on day 10. Contrast analyses characterized severe C. pneumoniae disease as being a delayed-type hypersensitivity (DTH) response with increased lung macrophage and Th1 cell marker transcripts, increased Th1:Th2 ratios, and Th1 cytokine-driven inflammation. Results from functional analyses by DTH, enzyme-linked immunospot, and immunohistofluorescence assays were consistent with the results obtained by transcript analysis. Thus, chlamydial disease after secondary infection is a temporal dysregulation of the T-cell response characterized by a profoundly delayed T-helper cell response that results in a failure to eliminate the pathogen and provokes later pathological Th1 inflammation. This delayed T-cell response is under host genetic control and nutritional influence. The mechanism that temporally and quantitatively regulates the host T-cell population is the critical determinant in chlamydial pathogenesis.

Growth-deficient vomeronasal organs in the naked mole-rat (Heterocephalus glaber).

The naked mole-rat (Heterocephalus glaber) is unusual in numerous life history characteristics as well as its eusocial organization. This species demonstrates widespread sexual suppression and prominent scent marking, behaviors that have been associated with pheromonal communication involving the vomeronasal organ in other rodents. Yet, previous studies indicate that urinary signals do not mediate sexual suppression in Heterocephalus. Surprisingly, no previous studies have examined the vomeronasal organ in this species. Here, we show that Heterocephalus is unique among rodents in showing no evidence of postnatal volumetric growth in the vomeronasal neuroepithelium. Subadults from birth to weaning fell within the same volume range as adults regardless of breeding/non-breeding status of the latter. A comparison of existing ontogenetic data on other mammals suggests that the proportionally small VNOs of Heterocephalus may be explained by a deficiency in VNNE growth. Growth deficiency of the vomeronasal organ in Heterocephalus may relate to a diminished role that pheromones play in certain social interactions for this species, such as breeding suppression. In light of the unique aspects of the vomeronasal organ in Heterocephalus, comparative studies of rodents may provide a model for understanding variation of this sensory system in other mammalian orders including primates, an order which shows a range from vestigial to demonstrably functional vomeronasal organs.

Perinatal size and maturation of the olfactory and vomeronasal neuroepithelia in lorisoids and lemuroids.

Explanations for the chemosensory abilities of newborn mammals focus primarily on food (milk) acquisition and communication (e.g., maternal-infant bonding). However, the relative importance of the main and accessory (vomeronasal) olfactory systems is hypothesized to differ at birth between altricial and precocial mammals. Strepsirrhines (lemurs and lorises) possess main and accessory olfactory systems, and vary in life-history traits related to infant dependency and maturation. Accordingly, this study examines the size and maturational characteristics of vomeronasal (VNNE) and olfactory (OE) neuroepithelia in strepsirrhines. Serially sectioned heads of 18 infant cadavers were examined microscopically for neuroepithelial distribution. Measurements were taken on the length of the nasal fossa on one side that was occupied by VNNE and OE. The data were corrected for body size using the cranial length or body mass, and were then examined for correlation with several life-history variables, as well as activity pattern. In addition, immunohistochemistry was used to identify cells in the VNNE and OE that express olfactory marker protein (OMP), a marker of mature olfactory neurons. Relative OE extent was not significantly correlated with any of the life-history variables. Relative VNNE length was negatively correlated with relative gestation length and relative neonatal mass (P<0.05). However, when we corrected for phylogenetic relationships, we found no significant correlations between either of the neuroepithelial measurements and life-history variables. Immunohistochemical findings suggest that OE has more OMP-reactive cells than VNNE in all species. OMP-reactive cells appear to be less numerous in diurnal species compared to most nocturnal species. These results indicate that the VNNE may be relatively longer at birth in altricial species. However, it remains uncertain how phylogeny and/or ontogeny may explain these findings.

Endothelin-1 inhibits adiponectin secretion through a phosphatidylinositol 4,5-bisphosphate/actin-dependent mechanism.

Adiponectin is an adipokine with profound insulin-sensitizing, anti-inflammatory, and anti-atherogenic properties. Plasma levels of adiponectin are reduced in insulin resistant states such as obesity, type 2 diabetes and cardiovascular disease. However, the mechanism(s) by which adiponectin concentrations are decreased during disease development is unclear. Studies have shown that endothelin-1 (ET-1), a vasoconstrictor peptide, affects adipocyte glucose metabolism and secretion of adipokines such as leptin, resistin, and adiponectin. The goal of our study was to determine the mechanism by which ET-1 decreases adiponectin secretion. 3T3-L1 adipocytes were treated for 24h with ET-1 (10nM) and then stimulated with vehicle or insulin (100 nM) for a period of 1-2h. Chronic ET-1 (24h) treatment significantly decreased basal and insulin-stimulated adiponectin secretion by 66% and 47%, respectively. Inhibition of phosphatidylinositol 4,5-bisphosphate (PIP(2)) hydrolysis by the PLCbeta inhibitor, U73122, or exogenous addition of PIP(2):histone carrier complex (1.25:0.625 microM) ameliorated the decrease in basal and insulin-stimulated adiponectin secretion observed with ET-1. However, treatment with exogenous PIP(2):histone carrier complex and the actin depolymerizing agent latrunculin B (20 microM) did not reverse the ET-1-mediated decrease in adiponectin secretion. In conclusion, we demonstrate that ET-1 inhibits basal and insulin-stimulated adiponectin secretion through PIP(2) modulation of the actin cytoskeleton.