Browsing by Author "Gao, Yong"
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Item Cumulative Effects of Neonatal Hyperoxia on Murine Alveolar Structure and Function(Wiley, 2017-05) Cox, Angela M.; Gao, Yong; Perl, Anne-Karina T.; Tepper, Robert S.; Ahlfeld, Shawn K.; Pediatrics, School of MedicineBackground Bronchopulmonary dysplasia (BPD) results from alveolar simplification and abnormal development of alveolar and capillary structure. Survivors of BPD display persistent deficits in airflow and membrane and vascular components of alveolar gas diffusion. Despite being the defining feature of BPD, various neonatal hyperoxia models of BPD have not routinely assessed pulmonary gas diffusion. Methods To simulate the most commonly-utilized neonatal hyperoxia models, we exposed neonatal mice to room air or ≥90% hyperoxia during key stages of distal lung development: through the first 4 (saccular), 7 (early alveolar), or 14 (bulk alveolar) postnatal days, followed by a period of recovery in room air until 8 weeks of age when alveolar septation is essentially complete. We systematically assessed and correlated the effects of neonatal hyperoxia on the degree of alveolar–capillary structural and functional impairment. We hypothesized that the degree of alveolar–capillary simplification would correlate strongly with worsening diffusion impairment. Results Neonatal hyperoxia exposure, of any duration, resulted in alveolar simplification and impaired pulmonary gas diffusion. Mean Linear Intercept increased in proportion to the length of hyperoxia exposure while alveolar and total lung volume increased markedly only with prolonged exposure. Surprisingly, despite having a similar effect on alveolar surface area, only prolonged hyperoxia for 14 days resulted in reduced pulmonary microvascular volume. Estimates of alveolar and capillary structure, in general, correlated poorly with assessment of gas diffusion. Conclusion Our results help define the physiological and structural consequences of commonly-employed neonatal hyperoxia models of BPD and informtheir clinical utility.Item Initial Suppression of Transforming Growth Factor-β Signaling and Loss of TGFBI Causes Early Alveolar Structural Defects Resulting in Bronchopulmonary Dysplasia(Elsevier, 2016-04) Ahlfeld, Shawn K.; Wang, Wang; Gao, Yong; Snider, Paige; Conway, Simon J.; Pediatrics, School of MedicineSeptation of the gas-exchange saccules of the morphologically immature mouse lung requires regulated timing, spatial direction, and dosage of transforming growth factor (TGF)-β signaling. We found that neonatal hyperoxia acutely initially diminished saccular TGF-β signaling coincident with alveolar simplification. However, sustained hyperoxia resulted in a biphasic response and subsequent up-regulation of TGF-β signaling, ultimately resulting in bronchopulmonary dysplasia. Significantly, we found that the TGF-β–induced matricellular protein (TGFBI) was similarly biphasically altered in response to hyperoxia. Moreover, genetic ablation revealed that TGFBI was required for normal alveolar structure and function. Although the phenotype was not neonatal lethal, Tgfbi-deficient lungs were morphologically abnormal. Mutant septal tips were stunted, lacked elastin-positive tips, exhibited reduced proliferation, and contained abnormally persistent alveolar α-smooth muscle actin myofibroblasts. In addition, Tgfbi-deficient lungs misexpressed TGF-β–responsive follistatin and serpine 1, and transiently suppressed myofibroblast platelet-derived growth factor α differentiation marker. Finally, despite normal lung volume, Tgfbi-null lungs displayed diminished elastic recoil and gas exchange efficiency. Combined, these data demonstrate that initial suppression of the TGF-β signaling apparatus, as well as loss of key TGF-β effectors (like TGFBI), underlies early alveolar structural defects, as well as long-lasting functional deficits routinely observed in chronic lung disease of infancy patients. These studies underline the complex (and often contradictory) role of TGF-β and indicate a need to design studies to associate alterations with initial appearance of phenotypical changes suggestive of bronchopulmonary dysplasia.Item Mu opioid receptors on vGluT2‐expressing glutamatergic neurons modulate opioid reward(Wiley, 2021-05) Reeves, Kaitlin C.; Kube, Megan J.; Grecco, Gregory G.; Fritz, Brandon M.; Muñoz, Braulio; Yin, Fuqin; Gao, Yong; Haggerty, David L.; Hoffman, Hunter J.; Atwood, Brady K.; Pharmacology and Toxicology, School of MedicineThe role of Mu opioid receptor (MOR)-mediated regulation of GABA transmission in opioid reward is well established. Much less is known about MOR-mediated regulation of glutamate transmission in the brain and how this relates to drug reward. We previously found that MORs inhibit glutamate transmission at synapses that express the Type 2 vesicular glutamate transporter (vGluT2). We created a transgenic mouse that lacks MORs in vGluT2-expressing neurons (MORflox-vGluT2cre) to demonstrate that MORs on the vGluT2 neurons themselves mediate this synaptic inhibition. We then explored the role of MORs in vGluT2-expressing neurons in opioid-related behaviors. In tests of conditioned place preference, MORflox-vGluT2cre mice did not acquire place preference for a low dose of the opioid, oxycodone, but displayed conditioned place aversion at a higher dose, whereas control mice displayed preference for both doses. In an oral consumption assessment, these mice consumed less oxycodone and had reduced preference for oxycodone compared with controls. MORflox-vGluT2cre mice also failed to show oxycodone-induced locomotor stimulation. These mice displayed baseline withdrawal-like responses following the development of oxycodone dependence that were not seen in littermate controls. In addition, withdrawal-like responses in these mice did not increase following treatment with the opioid antagonist, naloxone. However, other MOR-mediated behaviors were unaffected, including oxycodone-induced analgesia. These data reveal that MOR-mediated regulation of glutamate transmission is a critical component of opioid reward.Item Neonatal hyperoxic lung injury favorably alters adult right ventricular remodeling response to chronic hypoxia exposure(American Physiological Society, 2015-04-15) Goss, Kara N.; Cucci, Anthony R.; Fisher, Amanda J.; Albrecht, Marjorie; Frump, Andrea; Tursunova, Roziya; Gao, Yong; Brown, Mary Beth; Petrache, Irina; Tepper, Robert S.; Ahlfeld, Shawn K.; Lahm, Tim; Department of Medicine, IU School of MedicineThe development of pulmonary hypertension (PH) requires multiple pulmonary vascular insults, yet the role of early oxygen therapy as an initial pulmonary vascular insult remains poorly defined. Here, we employ a two-hit model of PH, utilizing postnatal hyperoxia followed by adult hypoxia exposure, to evaluate the role of early hyperoxic lung injury in the development of later PH. Sprague-Dawley pups were exposed to 90% oxygen during postnatal days 0-4 or 0-10 or to room air. All pups were then allowed to mature in room air. At 10 wk of age, a subset of rats from each group was exposed to 2 wk of hypoxia (Patm = 362 mmHg). Physiological, structural, and biochemical endpoints were assessed at 12 wk. Prolonged (10 days) postnatal hyperoxia was independently associated with elevated right ventricular (RV) systolic pressure, which worsened after hypoxia exposure later in life. These findings were only partially explained by decreases in lung microvascular density. Surprisingly, postnatal hyperoxia resulted in robust RV hypertrophy and more preserved RV function and exercise capacity following adult hypoxia compared with nonhyperoxic rats. Biochemically, RVs from animals exposed to postnatal hyperoxia and adult hypoxia demonstrated increased capillarization and a switch to a fetal gene pattern, suggesting an RV more adept to handle adult hypoxia following postnatal hyperoxia exposure. We concluded that, despite negative impacts on pulmonary artery pressures, postnatal hyperoxia exposure may render a more adaptive RV phenotype to tolerate late pulmonary vascular insults.Item Noninvasive monitoringn of CCl4 induced acute and chronic liver damage in rat by single quantum and triple quantum filtered 23Na magnetic resonance imaging(2008) Gao, Yong; Bansal, Navin; Babsky, Andriy M.; Kempson, Stephen A.; Basile, David P.In present study, single quantum (SQ) and triple quantum filtered (TQF) 23Na magnetic resonance imaging (MRI) was used to monitor the severity and progression of CCl4 induced acute and chronic liver damage in rat model. SQ 23Na MRI was proposed to measure the 23Na signal intensity (SI) of total tissue sodium ions, and TQF 23Na MRI was proposed to measure the SI of intracellular sodium ions. In addition, shift reagent aided 23Na and 31P magnetic resonance spectroscopy (MRS) was used to measure in vivo intracellular sodium concentration ([Na+i]), total tissue sodium concentration ([Na+t]) and relative extracellular space (rECS) of liver in the same model. In acute high dose CCl4 intoxication, 24 hours after single dose of CCl4 in 5ml per kg body weight of mixture of CCl4 and oil in 1:1 ratio, SQ 23Na SI increased by 83% and TQF 23Na SI increased by 174% compared to the baseline level. According to SR-aided 23Na and 31P MRS, [Na+i] increased by 188% and [Na+t] increased by 43%. In addition, there was significant decrease in cellular energetic level, represented by ATP/Pi ratio. Histology examination showed pronounced inflammatory response in centrilobular regions, with neutrophiles infiltration, fatty accumulation and swollen hepatocytes. In chronic 8-week experiment, chronic damage was induced by biweekly administration of CCl4 in a dosage of 0.5 ml per kg body weight. From week 1 to week 6, SQ 23Na SI remained relatively constant, and then increased by 15% from week 6 to week 8. TQF 23Na SI progressively increased from week 1 to week 8, totally by 56%. Both SQ and TQF 23Na SI showed significant difference between treated group and control at every week. SR-aided 23Na and 31P MRS experiment showed that, at the end of 8-week CCl4 intoxication, both [Na+t] and rECS were higher than control, by 49% and 47% respectively; however, there was no significant difference for [Na+i] between two groups. Histology examination showed excessive deposition of extracellular matrix. In conclusion, SQ and TQF 23Na MRI appears valuable in the functional assessment of liver in noninvasive approach, and could be a promising diagnostic modality for liver diseases in clinical area.Item Prenatal methadone exposure disrupts behavioral development and alters motor neuron intrinsic properties and local circuitry(eLife Sciences, 2021-03-16) Grecco, Gregory G.; Mork, Briana E.; Huang, Jui-Yen; Metzger, Corinne E.; Haggerty, David L.; Reeves, Kaitlin C.; Gao, Yong; Hoffman, Hunter; Katner, Simon N.; Masters, Andrea R.; Morris, Cameron W.; Newell, Erin A.; Engleman, Eric A.; Baucum, Anthony J.; Kim, Jiuen; Yamamoto, Bryan K.; Allen, Matthew R.; Wu, Yu-Chien; Lu, Hui-Chen; Sheets, Patrick L.; Atwood, Brady K.; Pharmacology and Toxicology, School of MedicineDespite the rising prevalence of methadone treatment in pregnant women with opioid use disorder, the effects of methadone on neurobehavioral development remain unclear. We developed a translational mouse model of prenatal methadone exposure (PME) that resembles the typical pattern of opioid use by pregnant women who first use oxycodone then switch to methadone maintenance pharmacotherapy, and subsequently become pregnant while maintained on methadone. We investigated the effects of PME on physical development, sensorimotor behavior, and motor neuron properties using a multidisciplinary approach of physical, biochemical, and behavioral assessments along with brain slice electrophysiology and in vivo magnetic resonance imaging. Methadone accumulated in the placenta and fetal brain, but methadone levels in offspring dropped rapidly at birth which was associated with symptoms and behaviors consistent with neonatal opioid withdrawal. PME produced substantial impairments in offspring physical growth, activity in an open field, and sensorimotor milestone acquisition. Furthermore, these behavioral alterations were associated with reduced neuronal density in the motor cortex and a disruption in motor neuron intrinsic properties and local circuit connectivity. The present study adds to the limited body of work examining PME by providing a comprehensive, translationally relevant characterization of how PME disrupts offspring physical and neurobehavioral development.Item Prenatal Opioid Administration Induces Shared Alterations to the Maternal and Offspring Gut Microbiome: A Preliminary Analysis(Elsevier, 2021) Grecco, Gregory G.; Gao, Yong; Gao, Hongyu; Liu, Yunlong; Atwood, Brady K.; Pharmacology and Toxicology, School of MedicineBackground: While many studies have described the impact of prenatal opioid exposure on development, possible mechanisms for how opioids exert developmental impairments remain elusive. Emerging evidence indicates disruptions in the maternal gut microbiome can alter offspring development; however, no studies to date have examined the impact of maternal opioid treatment on maternal-offspring microbiome dysbiosis. Methods: A mouse model of prenatal methadone exposure (PME) was employed to assess the impact of maternal opioid treatment on the microbiome of methadone-treated dams (MD) and their offspring. Fecal samples were collected from dams (n=8 per treatment), one male and one female offspring per dam (n=8 offspring per sex per treatment) for 16s rRNA sequencing. Results: Methadone treatment significantly increased the microbial diversity and led to an expansion in family level bacterial abundance. Correlational analysis revealed significant positive associations between dam and offspring measures of diversity indicating methadone-induced shifts in the microbial communities are shared between dam and offspring. Sixteen features in dams and 10 features in offspring were significantly differentially abundant between treatment groups with many features corresponding to the Lachnospiraceae NK4A136 genus. Of the six features identified as differentially abundant in both MD and PME offspring, all were assigned to the Lachnospiraceae NK4A136 group, and the abundances demonstrated strong positive correlations between dam and offspring. Conclusions: These preliminary findings indicate that maternal opioid treatment during pregnancy alters the composition of the maternal microbiome, and this opioid-induced shift is similarly observed in offspring which could contribute to the impaired developmental phenotypes previously described.Item Prenatal Opioid Exposure Impairs Endocannabinoid and Glutamate Transmission in the Dorsal Striatum(Society for Neuroscience, 2022-04-20) Grecco, Gregory G.; Muñoz, Braulio; Di Prisco, Gonzalo Viana; Doud, Emma H.; Fritz, Brandon M.; Maulucci, Danielle; Gao, Yong; Mosley, Amber L.; Baucum, Anthony J.; Atwood, Brady K.; Pharmacology and Toxicology, School of MedicineThe opioid crisis has contributed to a growing population of children exposed to opioids during fetal development; however, many of the long-term effects of opioid exposure on development are unknown. We previously demonstrated that opioids have deleterious effects on endocannabinoid plasticity at glutamate synapses in the dorsal striatum of adolescent rodents, but it is unclear whether prenatal opioid exposure produces similar neuroadaptations. Using a mouse model of prenatal methadone exposure (PME), we performed proteomics, phosphoproteomics, and patch-clamp electrophysiology in the dorsolateral striatum (DLS) and dorsomedial striatum (DMS) to examine synaptic functioning in adolescent PME offspring. PME impacted the proteome and phosphoproteome in a region- and sex-dependent manner. Many proteins and phosphorylated proteins associated with glutamate transmission were differentially abundant in PME offspring, which was associated with reduced glutamate release in the DLS and altered the rise time of excitatory events in the DMS. Similarly, the intrinsic excitability properties of DMS neurons were significantly affected by PME. Last, pathway analyses revealed an enrichment in retrograde endocannabinoid signaling in the DLS, but not in the DMS, of males. Electrophysiology studies confirmed that endocannabinoid-mediated synaptic depression was impaired in the DLS, but not DMS, of PME-males. These results indicate that PME induces persistent neuroadaptations in the dorsal striatum and could contribute to the aberrant behavioral development described in offspring with prenatal opioid exposure.Item Prenatal Opioid Exposure Reprograms the Behavioral Response to Future Alcohol Reward(Wiley, 2022) Grecco, Gregory G.; Haggerty, David L.; Reeves, Kaitlin C.; Gao, Yong; Maulucci, Danielle; Atwood, Brady K.; Pharmacology and Toxicology, School of MedicineAs the opioid crisis has continued to grow, so too has the number of infants exposed to opioids during the prenatal period. A growing concern is that prenatal exposure to opioids may induce persistent neurological changes that increase the propensity for future addictions. Although alcohol represents the most likely addictive substance that the growing population of prenatal opioid exposed will encounter as they mature, no studies to date have examined the effect of prenatal opioid exposure on future sensitivity to alcohol reward. Using a recently developed mouse model of prenatal methadone exposure (PME), we investigated the rewarding properties of alcohol and alcohol consumption in male and female adolescent PME and prenatal saline exposed (PSE) control animals. Conditioned place preference to alcohol was disrupted in PME offspring in a sex-dependent manner with PME-males exhibiting resistance to the rewarding properties of alcohol. Repeated injections of alcohol revealed enhanced sensitivity to the locomotor stimulating effects of alcohol specific to PME-females. PME-males consumed significantly more alcohol over four weeks of alcohol access relative to PSE-males and exhibited increased resistance to quinine-adulterated alcohol. Further, a novel machine learning model was developed to employ measured differences in alcohol consumption and drinking microstructure to reliably predict prenatal exposure. These findings indicate that PME alters the sensitivity to alcohol reward in adolescent mice in a sex-specific manner and suggests prenatal opioid exposure may induce persistent effects on reward neurocircuitry that can reprogram offspring behavioral response to alcohol later in life.Item Relationship of structural to functional impairment during alveolar-capillary membrane development(Elsevier, 2015-04) Ahlfeld, Shawn K.; Gao, Yong; Conway, Simon J.; Tepper, Robert S.; Department of Pediatrics, IU School of MedicineBronchopulmonary dysplasia is a chronic lung disease of extreme preterm infants and results in impaired gas exchange. Although bronchopulmonary dysplasia is characterized histologically by alveolar-capillary simplification in animal models, it is clinically defined by impaired gas diffusion. With the use of a developmentally relevant model, we correlated alveolar-capillary structural simplification with reduced functional gas exchange as measured by the diffusing factor for carbon monoxide (DFCO). Neonatal mouse pups were exposed to >90% hyperoxia or room air during postnatal days 0 to 7, and then all pups were returned to room air from days 7 to 56. At day 56, DFCO was measured as the ratio of carbon monoxide uptake to neon dilution, and lungs were fixed for histologic assessment of alveolar-capillary development. Neonatal hyperoxia exposure inhibited alveolar-capillary septal development as evidenced by significantly increased mean linear intercept, increased airspace-to-septal ratio, decreased nodal density, and decreased pulmonary microvasculature. Importantly, alveolar-capillary structural deficits in hyperoxia-exposed pups were accompanied by a significant 28% decrease in DFCO (0.555 versus 0.400; P < 0.0001). In addition, DFCO was highly and significantly correlated with structural measures of reduced alveolar-capillary growth. Simplification of alveolar-capillary structure is highly correlated with impaired gas exchange function. Current mechanistic and therapeutic animal models of inhibited alveolar development may benefit from application of DFCO as an alternative physiologic indicator of alveolar-capillary development.