Indiana University-Purdue University Indianapolis (IUPUI) / Non-alcoholic fatty liver disease and metabolic syndrome induced by high nutrient status have increasingly become a global health concern as it cause multiple complications. The mTOR complex is central in regulating anabolic reactions within cells under growth factors or under high nutrients stimulation. Constitutive and persistent activation of mTOR can impair cellular functions. In the first part of this study, we demonstrate a damping oscillation of mTOR activity during a long-term treatment of high fat diet. TFEB translocation and lysosomal enzyme activity also oscillate, but in an opposite direction. TFEB controls the lysosomal activity, autophagic degradation and lipid metabolism. Overexpression of wild type and mutant TFEB could inhibit NAFLD development in mice. In addition, TFEB location in nucleus inversely correlates with NAFLD severity in patients. mTOR activation under hypernutrition status suppresses TFEB translocation, inhibits lysosomal functions and autophagic degradation of lipid droplets. Inhibition of mTOR activity by rapamycin reverse the above phenotypes. Because mTOR activation also requires normal lysosomal function, the inhibition of TFEB by mTOR leads to decreased lysosomal function and mTOR downregulation. This negative feedback may explain the oscillation pattern of mTOR activation in long term high fat diet regimen and is a novel mechanism for inhibition of mTOR. In the second part of study, we report that Bid protein, previously known for its pro-apoptosis function in promoting mitochondrial permeability, plays an unexpected role in regulating fatty acid beta oxidation. Deletion of Bid in mice reprograms the body's response to hyper-nutrition caused by high fat diet, leading to the resistance to the development of obesity, liver steatosis and metabolic syndrome. These mice present a higher oxygen consumption, a lower respiratory quotient, and an increased beta-oxidation rate. Mechanistically, the high fat diet regimen triggers translocation of the full length Bid molecule to mitochondrial membrane. Genetic deletion of Bid also affects the stability of its binding protein, MTCH2 in the mitochondrial membrane. In summary, we describe in this study a mTOR-TFEB-lysosome feedback loop, which can regulate NAFLD development, and a novel Bid-mediated regulatory mechanism in beta-oxidation, which limits energy expenditure and promotes obesity development.

Despite decades of research on amphetamine derivatives, a class of compounds sharing a structural foundation with amphetamine, crucial gaps remain in our understanding of these drugs in a variety of animal species and humans. This dissertation addresses three of these gaps through a multi-level approach involving studies in both humans and mice. Specifically, it focuses on investigating the lack of information regarding: 1) repeated dosing of 3,4-methylenedioxymethamphetamine in humans, 2) methamphetamine/alcohol combinations in humans and 3) methamphetamine/oxycodone combinations in mice. Study 1 involved administering three consecutive doses of 3,4 methylenedioxymethamphetamine to human volunteers at 12- and 24-hour intervals while physiological, behavioral, and subjective measures were collected. Study 2 reanalyzed Kirkpatrick and colleagues (2012a) data to evaluate repeated administrations of methamphetamine and alcohol. The reanalysis focused on quantifying the physiological and subjective effect differences between the first and second administrations, which occurred at a 12-hour interval on the same day, an aspect not previously analyzed or reported by the original authors. Study 3 utilized well-established animal models such as Conditioned Place Preference, Open Field Test, and Novel Object Recognition to evaluate the reward-like and aversive effects of methamphetamine and oxycodone combinations in mice. Study 1 was the first to quantify the effects of multiple 3,4-methylenedioxymethamphetamine doses administered over a 36-hour period of time. Initially, acute 3,4-methylenedioxymethamphetamine produced dose-dependent increases in peak heart rate, blood pressure, and more positive than negative subjective effects. However, by the third dose, many of these effects dissipated, heart rate was no longer elevated, and residual mood effects were minor. Overall, the data do not support the general perception that 3,4-methylenedioxymethamphetamine produces dangerous cardiovascular and residual mood effects in humans following repeated administration. The results of Study 2, again a first in the field, discovered that contrary to expectations, heart rate increases produced by the methamphetamine/alcohol combination were not further increased with repeated dosing, but rather attenuated. In fact, methamphetamine offset alcohol-induced intoxication, even after repeated administration. Study 3 revealed that combining methamphetamine and oxycodone in mice increased reward as measured by Conditioned Place Preference, but not more than either drug alone. However, methamphetamine lengthened the duration of Conditioned Place Preference for the lower oxycodone dose and offset the oxycodone-induced disruptions in novel object recognition performance. One crucial cross-species observation was that methamphetamine mitigated adverse effects such as alcohol-related intoxication and oxycodone cognitive disruption, even after repeated administration. While seemingly beneficial, this observation raises concerns that individuals who combine these drugs may be at risk of underestimating their overall degree of impairment, potentially leading to hazardous activities like driving while intoxicated or engaging in risky behaviors. Sharing this insight is crucial to encourage informed, responsible behavior and safeguard public safety. In conclusion, these studies have significantly enhanced our understanding of two frequently used amphetamine derivatives and their interactions with two commonly used psychoactive drugs—oxycodone and alcohol. Most importantly, we strongly advocate for robust empirical experimentation to counteract misinformation related to 3,4-methylenedioxymethamphetamine and methamphetamine. These endeavors are crucial for developing more precise assessments of the risks and benefits associated with these substances, and for improving drug policies and optimizing public health interventions.

For glutamate and the developing optic pathway, glutamate and its ionotropic receptor subunits are expressed widely in retina and ventral diencephalon, and in cells that are related to the chiasm formation. These studies indicate that glutamate may act as a communicator or attractor to coordinate with other factors to affect the retinal axon pathfinding in the prenatal optic pathway. / Furthermore, for the function of glutamate, AMPARs and KARs in the optic chiasm formation, we did retinal explant culture experiment at E14 in vitro, with application of different concentration of L-glutamate (500muM -1mM), AMPAR antagonists: CP465022 hydrochloride (2-20muM) and GYK15466 dihydrochloride (25-150muM), and KAR antagonists: CNQX (50-500muM) and UBP301 (5-25muM). The results show that L-glutamate promotes retinal axon outgrowth; AMPA receptor antagonists inhibit that; and KAR antagonists have no effect on that. In the presence of different combinations of ionotropic receptor antagonists (including NMDAR antagonist), they suggest that the blockage of glutamate iontroptic receptors displays an obvious effect of inhibiting neurite outgrowth in E14 retinal explants. However, inhibiting kainate receptors show little effect on retinal neurite outgrowth which is different from that of blocking AMPARs. We also did E13 and E15 brain slice culture experiments, and found that blocking of glutamate ionotropic receptors affects crossed axon projection in the midline at early stage, but has no effect to the uncrossed one. / Glutamate is the dominant amino acid neurotransmitter in the central nervous system naturally occurring in the L-form. Glutamate ionotropic receptors can be further a-amino-3-hydroxy-5-methy1-4-isoxazole-propionate divided into three types by their ligand (AMPA, specificities: GluR1-4), N-methyl-D-aspartate (NMDA, NR1-3) and kainate (KA, GluR5-7 and KA1-2) receptors, which function as ligand-gated ion channels. In this study, we focus on the AMPARs and KARs which are expressed in the developing brain. / Here, we used semi-quantitative RT-PCR to analyze mRNA expression levels of AMPAR and KAR subunits in the mouse retina and ventral diencephalons at different developmental stages, and in adult retina. The results show that both AMPAR and KAR subunits can be detected in retina and ventral diencephalon at as early as E13. We also used specific antibodies to investigate glutamate, AMPAR and KAR subunit expression in the mouse retinofugal pathway. We found that: 1) Glutamate is expressed at as early as E13. In retina, it tends to localize in retinal ganglion cells (RGCs) and their axons; in ventral diencephalon, it is most intense in optic stalk, optic chiasm and optic tract. It is also localized with chiasmatic neurons, which are related to the formation of optic chiasm. 2) For the individual AMPAR and KAR subunits, all of them are expressed at as early as E13. The immunoreactive GluRl and GluR5/6/7 are distributed preferentially in the RGCs and their axons; the staining of GluR2/3 and GluR4 are largely found in RGCs and the supporting cells around the pathway, but for GluR4, its staining is weakly detected in optic fibers and strongly in the midline of chiasm. Although the staining patterns of these specific subunits are different, they are all localized in chiasmatic neurons in diencephalon. / Cheng, Xiaojing. / "November 2010." / Adviser: Sun On Chan. / Source: Dissertation Abstracts International, Volume: 73-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 137-152). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Background. The kidney is one of the major organs involved in whole-body homeostasis and it is well understood that chronic renal impairment is further complicated with deranged carbohydrate metabolism, dyslipidemia, altered abdominal fat distribution and the activation of renin-angiotensin system (RAS). Recently, RAS blockades of angiotensinconverting enzyme inhibitor (ACEI) and angiotensin II receptor blocker (ARB) have been noticed for their potential effects on improve glucose and lipid metabolisms and lowering the risk of new-onset diabetes. However, underlying cellular and molecular mechanisms are not fully established. / Conclusions. (1) UNX induces progressive renal impairment and dysregulation of pancreatic and renal RAS in rats. (2) Pancreatic RAS activation leads to intra-islet fibrosis, insulin-secreting beta-cell deficit and insulin secretory deficiency. (3) Renal cortex RAS dysregulation induces ectopic adipocyte differentiation and lipid infiltration, in combination with lipodystrophy and lipid peroxidation, results to insulin resistance. (4) Pancreatic insulin-secretion deficit and insulin resistance contribute to the development of glucose intolerance and hyperglycemia. (5) Kidney impacting on glucose and lipid metabolism by affecting pancreatic islet and adipocyte, suggesting an essential role of the kidney in maintaining the whole-body homeostasis. (6) RAS blockade with ACEI or ARB may prevent the development of chronic renal impairment and glucose and lipid dysmetabolisms in UNX rats. (7) Common pathways modulating blood pressure, glucose and lipid metabolism warrant future studies for the better management of the global epidemic of metabolic syndrome. / Materials and methods. Chronic renal impairment and RAS disturbance were induced by unilateral nephrectomy (UNX) in adult Sprague-Dawley rats undergoing as long as 10 months of observation. Three-month old male rats were randomized into 4 groups: (1) sham operated control rats (n=10), (2) untreated UNX model rats (n=10), (3) ACEI---lisinopril treated UNX rats (n=10), and (4) ARB-olmesartan treated UNX rats (n=10). Blood glucose levels during fasting and oral glucose tolerance test (OGTT) conditions, lipids, insulin and renal function were measured at 3, 6, 8 and 10 months after operation. Histological changes of kidney, pancreas, liver, and adipose tissue were examined at 10 months post-operation. / Objectives. (1) To set up a rat model with persistent chronic renal impairment and RAS activation. (2) To examine changes of fasting blood glucose, glucose tolerance, blood lipids and insulin sensitivity. (3) To examine changes of pancreatic islets and the factors contributing to pancreatic islet damage such as RAS, transforming growth factor (TGF)-beta and alpha-smooth muscle actin (SMA). (4) To examine changes of systemic and renal adipose tissue and the factors contributing to adipopathy such as RAS, peroxisome proliferator-activated receptor-gamma (PPAR-gamma) and hydroxy-3-methylglutary coenzyme A reductase (HMGCR). (5) To investigate preventive effect of RAS blockades by the ACEI-lisinopril (4 mg/kg body weight) and ARB-olmesartan (4 mg/kg body weight) on the rat model of progressive renal deficiency. / Results. (1) UNX rats developed time-dependent progressive renal functional impairment and marked glomerulosclerosis and tubulointerstitial lesions. (2) UNX rats showed fasting hyperglycemia, progressive glucose intolerance, hyperlipidemia and insulin resistance. (3) UNX rats demonstrated insulin secretory deficiency in parallel to pancreatic islet fibrosis, beta-cell deficit, and overexpression of RAS components, TGF-beta, and alpha-SMA. (4) UNX rats displayed adipopathy evidenced by shifts the subcutaneous and visceral fats to the ectopic fat with lipid accumulation, lipofuscin pigmentation and adipocytes transformation. The adipopathy associated with down-regulation of AT1R and over-expression of angiotensin, AT2R, PPAR-gamma and HMGCR in the remnant kidney. (5) Treatment with lisinopril and olmesartan significantly attenuated the development of chronic renal impairment, RAS dysregulation and aberrant proteins expression, islet damage, adipose redistribution, and glucose and lipid dysmetabolism. / Sui, Yi. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3422. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 195-220). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

A population of stromal cells that retains osteogenic capacity in adult bone (adult bone stromal cells or aBSCs) exists and is under intense investigation in relation to osteogenesis and relevant pathology. aBSCs may be different from their embryonic or neonatal counterparts, and are influenced by species-/age-specific and other factors. Mice heterozygous for a null allele of prkar1a (Prkar1a+/-, a gene encoding for cyclic adenosine mono-phosphate (cAMP)-dependent regulatory subunit of protein kinase A (PKA), developed bone lesions that resembled fibrous dysplasia (FD) originated from cAMP-responsive osteogenic cells. Prkar1a +/- mice were crossed with mice heterozygous for catalytic subunit Calpha (Prkaca+/-), the main PKA activity-mediating molecule and generated mouse model with double heterozygosity for prkar1a and prkaca (Prkar1a +/-Prkaca+/-). Unexpectedly, Prkar1a+/-Prkaca+/- mice developed a large number of osseous lesions starting at 2--3 months of age that varied from the rare chondromas in the long bones and the ubiquitous osteochondrodysplasia of tail vertebral bodies to the occasional sarcoma in older animals. Cells from these lesions were fibroblast- and FD-like, and almost always originated from an area proximal to the growth plate and adjacent to endosteal surface of the periosteum; they expanded gradually in the bone marrow space. These cells expressed osteogenic cell markers, showed higher PKA activity that was mostly type II (PKA-II) and display an alternate pattern of catalytic subunit expression, and surprisingly possessed higher cAMP levels. In addition, markers of bone synthesis and lysis were increased. Gene expression profiling not only confirmed an early (progenitor) osteoblastic nature for these cells but also showed a signature that was indicative of mesenchymal-to-epithelial (MET) transition and increased Wnt signaling, particularly the brachyury expression. These studies show that a specific subpopulation of aBSCs can be stimulated in adult bone by PKA-II and altered Calpha activity, generating the only available germline mutant mouse model of a disorder that has similarities to human FD. Along with previous data, these studies also suggest that the effects of cAMP signaling on osteogenesis and stromal cell maintenance and proliferation in mice are age-, bone-, site- but also PKA-type and catalytic subunit-specific. / Parts of the work have been published in Proceedings of the National Academy of Sciences of the United States of America 2010; 107(19):8683--8. / Tsang, Kit Man. / Advisers: Constantine A. Stratakas; Kwak-Pui Fung. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 144-183). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

The inner ear, the sensory organ responsible for hearing and balance, contains specialized sensory and non-sensory epithelia arranged in a highly complex threedimensional structure. To achieve this complexity, a tight coordination between morphogenesis and cell fate specification is essential during otic development. Tisúes surrounding the otic primordium, and more particularly the adjacent segmented hindbrain, have been implicated in specifying structures along the anteroposterior and dorsoventral axes of the inner ear. In this work we have first characterized the generation and axial specification of the otic neurogenic domain, and second, we have investigated the effects of the mutation of kreisler/MafB -a gene transiently expressed in the rhombomeres 5 and 6 of the developing hindbrain- in early otic patterning and cell specification. We show that kr/kr embryos display an expansion of the otic neurogenic domain, due to defects in otic patterning. Although many reports have pointed to the role of FGF3 in otic regionalization, we provide evidence that FGF3 is not sufficient to govern this process. Neither Krox20 nor Fgf3 null mutant embryos, in which Fgf3 is either downregulated or absent in r5 and r6, present ectopic otic neuroblasts in the otic primordium. However, Fgf3-/-Fgf10-/- double mutants show a phenotype very similar to kr/kr embryos: they present ectopic neuroblasts along the AP and DV otic axes. Finally, and remarkably, partial rescue of the kr/kr phenotype is obtained when Fgf3 or Fgf10 are ectopically expressed in the hindbrain of kr/kr embryos. These results highlight a compensatory mechanism between FGFs, and the importance of hindbrain-derived signals in instructing otic patterning and the establishment of the neurogenic domain.

PiRNAs and their Piwi family protein partners are part of a germline specific epigenetic regulatory mechanism essential for proper spermatogenesis, silencing of transposable elements, and maintaining germline genome integrity, yet their role in the response of the male germline to genotoxic stress is unknown. Ionizing radiation (IR) is known to cause transgenerational genome instability that is linked to carcinogenesis. Although the molecular etiology of IR-induced transgenerational genomic instability is not fully understood, it is believed to be an epigenetically mediated phenomenon. IR-induced alterations in the expression pattern of key regulatory proteins involved in the piRNA pathway essential for paternal germline genome stability may be directly involved in producing epigenetic alterations that can impact future generations. Here we show whole body and localized X-irradiation leads to significant altered expression of proteins that are necessary for, and intimately involved in, the proper functioning of the germline specific piRNA pathway in mice and rats. In addition we found that IR-induced alterations to piRNA pathway protein levels were time and dose dependent. / ix, 123 leaves : ill. (some col.) ; 29 cm

Most bacterial infections can be correlated to contamination of consumables such as food and water. Upon contamination, boil water advisories have been ordered to ensure water is safe to consume, despite the evidence that heat-killed bacteria can induce genomic instability of exposed (intestine) and distal cells (liver and spleen). We hypothesize that exposure to components of heat-killed Escherichia coli O157:H7 will induce genomic instability within animal cells directly and indirectly exposed to these determinants. Mice were exposed to various components of dead bacteria such as DNA, RNA, protein or LPS as well as to whole heat-killed bacteria via drinking water. Here, we report that exposure to whole heat-killed bacteria and LPS resulted in significant alterations in the steady state RNA levels and in the levels of proteins involved in proliferation, DNA repair and DNA methylation. Exposure to whole heat-killed bacteria and their LPS components also leads to increased levels of DNA damage. / xiv, 132 leaves : ill. (chiefly col.) ; 29 cm

Acute allograft rejection remains a major problem in solid organ transplantation, because rejection may lead to acute or chronic loss of graft function. The failure of certain anti-rejection prophylactic treatments suggests that several unexpected pathways might be involved in the rejection process.<p>The aim of our experiments was to investigate the effector mechanisms responsible for skin graft rejection in mice. To adress this question, we took advantage of the possibility to restrict the alloimmune response to isolated allogeneic MHC class II molecules or to isolated minor transplantation antigens, combined with the possibility to study separately the response of CD4+ or CD8+ T cells in mice deficient for Th1 or Th2 cytokines or cytotoxic molecules. We used the bm12 skin graft combination (C57BL/6 H2Kbm12 grafted on C57BL/6 H2Kb) as a model of single MHC class II disparity and the b2microglobulin skin graft model (C57BL/6 b2m+/+ grafted on C57BL/6 b2m-/-) as a model of minor transplantation antigen disparity. Our goal was to engage a limited number of effectors, trying in a second time to block each rejection pathway selectively. <p>We showed that Fas/FasL-mediated CD4+ T cells cytotoxicity, eosinophil recruitment, activation and degranulation induced by Th2 derived cytokines, and CD4-derived IFN-g production are involved in the rejection of grafts bearing either a single MHC class II disparity or b2m-derived minor histocompatibilty antigens. In addition, rejection of MHC class II disparate skin grafts also includes the participation of neutrophils, in particular conditions where the occurrence of the Th2/eosinophil pathway was prevented. <p>Altogether, our data show a multiplicity and a redundancy of the effector pathways participating in allograft rejection. Among the different effectors pathways identified, including effectors from both innate and adaptive immune systems, some act synergistically, whereas others act as alternative pathways, depending of the degree of donor-recipient mismatch. / Doctorat en Sciences médicales / info:eu-repo/semantics/nonPublished

Les reins jouent un rôle majeur dans la régulation de l'homéostasie acide-base. La production et l'excrétion rénale d'ammonium assurent environ deux tiers de l'excrétion nette d'acides dans les conditions normales et jusqu'à 90% en situation d'acidose métabolique. Bien que l'excrétion d'ammonium soit un processus finement régulé et capital au maintien de l'équilibre acido-basique, à ce jour aucun transporteur spécifique d'ammonium n'a été décrit chez les mammifères. Les protéines Rhésus Rhcg et Rhbg, membres distants de la famille des transporteurs d'ammonium Mep/Amt, semblaient de bons candidats à cette fonction. L'invalidation du gène Rhcg puis celle de Rhbg ont donc été entreprises chez la souris afin d'estimer leur rôle potentiel dans le transport de l'ammonium. / Doctorat en sciences, Spécialisation biologie moléculaire / info:eu-repo/semantics/nonPublished