Sequential and Batch Processing Methods of the EBP Learning Algorithm

Placental abnormalities can cause Pregnancy-Associated Disorders, including preeclampsia, intrauterine growth restriction, and placental insufficiency, resulting in complications for both the mother and fetus. Trophoblast cells within the labyrinthine layer of the placenta facilitate the exchange of nutrients, gases, and waste between mother and fetus; therefore, the development of this cell layer is critical for fetal development. As trophoblast cells differentiate, it is assumed their metabolism changes with their energy requirements. We hypothesize that proper regulation of trophoblast metabolism is a key component of normal placental development; therefore, we examined the role of AMP-activated kinase (AMPK, PRKAA1/2), a sensor of cellular energy status. Our previous studies have shown that AMPK knockdown alters both trophoblast differentiation and nutrient transport. In this study, AMPKα1/2 shRNA was used to investigate the metabolic effects of AMPK knockdown on SM10 placental labyrinthine progenitor cells before and after differentiation. Extracellular flux analysis confirmed that AMPK knockdown was sufficient to reduce trophoblast glycolysis, mitochondrial respiration, and ATP coupling efficiency. A reduction in AMPK in differentiated trophoblasts also resulted in increased mitochondrial volume. These data indicate that a reduction in AMPK disrupts cellular metabolism in both progenitors and differentiated placental trophoblasts. This disruption correlates to abortive trophoblast differentiation that may contribute to the development of Pregnancy-Associated Disorders

Debra Mayes - Explains Bench to Bedside

Dr. Mayes explains how studying an animal model can carry over to human patients in a short interview

Debra Mayes - Explains Bench to Bedside

Dr. Mayes explains how studying an animal model can carry over to human patients in a short interview

How Loss of Neurofibromin in Oligodendrocytes Affects the Brain

Neurofibromatosis type 1 patients are predisposed to central nervous system (CNS) phenotypes including enlarged brains, delayed acquisition of motor skills, brain tumors, and cognitive deficits. Imaging and pathologic analysis suggest that changes in white matter myelination may underlie both the enlargement of white matter tracts that contributes to megancephaly, and/or hyper-intense signals visualized on MRI. To study the role(s) of Nf1 and HRasin oligodendrocytes, we examined the optic nerve and corpus callosum,myelinated fiber tracts.We studiedNf1heterozygous mice,tamoxifen-induced Nf1 loss in mature oligodendrocytes (Plp-CreERT), and a new transgenic model in which the CNPase promoter drives expression of HRasG12V. Activated HRas and loss of Nf1 within oligo-lineage cells (PLPCre; Nf1fl+; &PLPCre; Nf1fl/fl) resulted in optic nerve enlargement. The corpus callosum of CNP-HRasG12V mice was also enlarged. Electron microscopy analysis revealed 3 phenotypes within the enlarged optic nerves. 1)When Nf1 was lost or HRas was activated within oligodendrocytes, the myelin was decompacted due to splitting at the intraperiod lines. The transgenic Nf1+/- mice, in which Nf1 loss is not restricted to oligo-lineage cells, displayed lesser myelin decompaction, and these mice did not have significantly enlarged optic nerves. 2) Enlarged axons accompanied the decompacted myelin within all models. 3) All Nf1 and Ras mouse models also showed an expansion of the perivascular astrocyticendfeet surrounding the vasculature. These phenotypes were also found within the corpus callosum. Thus, myelin and vascular phenotypesare not limited to a single myelinated fiber tract. These studies reveal a cell autonomous role for the Nf1/Ras pathway in the regulation of myelin compaction, and a non-cell autonomous role in the regulation of astrocyticendfeet surrounding brain capillaries

Anti-Tumor Effect of Doxycycline on Glioblastoma Cells

AIM: Glioblastoma multiforme (GBM) is the most common primary brain tumor in humans, and it is highly invasive. Doxycycline, first identified as an antimicrobial agent, is a nonspecific inhibitor of matrix metalloproteinases (MMPs). Our objective was to investigate the anti-MMP effect of doxycycline at therapeutically acceptable levels on glioma cells in vitro. METHODS: The MTT assay was used to determine the anti-proliferative effects of doxycycline. MMP2 activity and expression were determined by gelatinase zymography and real-time quantitative RT-PCR, respectively. Cell invasion was assessed by Matrigel invasion assay. RESULTS: Doxycycline exerted mild anti-proliferative effects on all three glioma cell lines (U251HF, U87 and LN229). In U251HF cells, doxycycline decreased extracellular MMP2 activity and reduced cell invasiveness. Moreover, MMP2 mRNA levels were not altered, suggesting that doxycycline regulates MMP2 activity post-translationally. Alternatively, doxycycline increased the expression and extracellular activity of MMP2 in U87 cells. This may reflect the cellular stress response related to the cytotoxic effects experienced by U87 cells in response to doxycycline exposure. CONCLUSION: Doxycycline in therapeutic concentrations decreases MMP2 activity and cell invasion in the most aggressive cell line tested, suggesting its potential as a therapeutic MMP inhibitor. The cytotoxic effects of doxycycline, however, can enhance MMP2 expression, and this deserves further exploration

Gender- and Region-Specific Changes in Estrogen Signaling in Aging Rat Brain Mitochondria

Recently epidemiological studies suggest females lose neuroprotection from neurodegenerative diseases as they go through menopause. It has been hypothesized that this neuroprotection is hormone‐dependent. The current study characterized cell signaling molecules downstream of estrogen receptor beta that are known to play a role in memory, PKC, ERK, and connexin‐43, in regions of the brain associated with memory decline in an attempt to elucidate significant changes that occur post‐estrus. Total whole cell lysates were compared to isolated mitochondrial protein because mitochondrial function is known to be altered during aging. As hypothesized, protein concentrations differed depending on age, gender, and brain region. Additionally, many of these changes occurred within mitochondria but not within whole cell lysates indicating that these are epigenetic alterations. These findings accentuate the complexity of aging and provide insight into the gender‐ specific cellular processes that occur throughout this process

Combining an Autologous Peripheral Nervous System “Bridge” and Matrix Modification by Chondroitinase Allows Robust, Functional Regeneration beyond a Hemisection Lesion of the Adult Rat Spinal Cord

Chondroitinase-ABC (ChABC) was applied to a cervical level 5 (C5) dorsal quadrant aspiration cavity of the adult rat spinal cord to degrade the local accumulation of inhibitory chondroitin sulfate proteoglycans. The intent was to enhance the extension of regenerated axons from the distal end of a peripheral nerve (PN) graft back into the C5 spinal cord, having bypassed a hemisection lesion at C3. ChABC-treated rats showed (1) gradual improvement in the range of forelimb swing during locomotion, with some animals progressing to the point of raising their forelimb above the nose, (2) an enhanced ability to use the forelimb in a cylinder test, and (3) improvements in balance and weight bearing on a horizontal rope. Transection of the PN graft, which cuts through regenerated axons, greatly diminished these functional improvements. Axonal regrowth from the PN graft correlated well with the behavioral assessments. Thus, many more axons extended for much longer distances into the cord after ChABC treatment and bridge insertion compared with the control groups, in which axons regenerated into the PN graft but growth back into the spinal cord was extremely limited. These results demonstrate, for the first time, that modulation of extracellular matrix components after spinal cord injury promotes significant axonal regeneration beyond the distal end of a PN bridge back into the spinal cord and that regenerating axons can mediate the return of useful function of the affected limb

Perinatal or Adult \u3cem\u3eNf1\u3c/em\u3e Inactivation using Tamoxifen-inducible PlpCre Each Cause Neurofibroma Formation

OBJECTIVES Neurofibromas are tumors initiated by biallelic mutation of the NF1 tumor suppressor gene in the Schwann cell lineage. One idea within the field suggests that Nf1loss must occur within progenitor cells present within a critical window during Schwann cell development in order for neurofibromas to form. To test this hypothesis and to examine whethermyelinating Schwann cells can serve as aneurofibroma cell of origin, Nf1 loss was induced at perinatal or adult timepoints using a tamoxifen-inducible Plp-CreERT driver. RESULTS Perinatal loss of Nf1 resulted in small neurofibromas late in life, while adult loss caused large neurofibromas and morbidity beginning 4 months after onset of Nf1loss. PLP-CreERT recombination (EGFP+ cells) occurred in: satellite cells, S100β+ myelinating Schwann cells, and p75+ cells. Plp-CreERTnerves and neurofibromas contained cells with Remak bundle disruption; however, no recombination within GFAP+ non-myelinating Schwann cells was identified. Extramedullarylympho-hematopoietic expansion that contained EGFP+/Sca-1+ stromal cells amongst EGFP-negative lympho-hematopoietic cells was also observed. CONCLUSIONS/SIGNIFICANCE Neurofibroma formation is not restricted to loss of Nf1 in embryonic life, but can be triggered by Nf1 loss throughout life.Although all neurofibroma models and human samples have Remak bundle disruption (leading to the assumption that Nf1 loss within the non-myelinating Schwann cell may be vital for tumor formation), there was no EGFP+ recombination within GFAP+ non-myelinating Schwann cells – eliminating the GFAP+ non-myelinating Schwann cell as the cell of origin for neurofibroma formation

How Loss of Neurofibromin in Oligodendrocytes Affects the Brain

Neurofibromatosis type 1 patients are predisposed to central nervous system (CNS) phenotypes including enlarged brains, delayed acquisition of motor skills, brain tumors, and cognitive deficits. Imaging and pathologic analysis suggest that changes in white matter myelination may underlie both the enlargement of white matter tracts that contributes to megancephaly, and/or hyper-intense signals visualized on MRI. To study the role(s) of Nf1 and HRasin oligodendrocytes, we examined the optic nerve and corpus callosum,myelinated fiber tracts.We studiedNf1heterozygous mice,tamoxifen-induced Nf1 loss in mature oligodendrocytes (Plp-CreERT), and a new transgenic model in which the CNPase promoter drives expression of HRasG12V. Activated HRas and loss of Nf1 within oligo-lineage cells (PLPCre; Nf1fl+; &PLPCre; Nf1fl/fl) resulted in optic nerve enlargement. The corpus callosum of CNP-HRasG12V mice was also enlarged. Electron microscopy analysis revealed 3 phenotypes within the enlarged optic nerves. 1)When Nf1 was lost or HRas was activated within oligodendrocytes, the myelin was decompacted due to splitting at the intraperiod lines. The transgenic Nf1+/- mice, in which Nf1 loss is not restricted to oligo-lineage cells, displayed lesser myelin decompaction, and these mice did not have significantly enlarged optic nerves. 2) Enlarged axons accompanied the decompacted myelin within all models. 3) All Nf1 and Ras mouse models also showed an expansion of the perivascular astrocyticendfeet surrounding the vasculature. These phenotypes were also found within the corpus callosum. Thus, myelin and vascular phenotypesare not limited to a single myelinated fiber tract. These studies reveal a cell autonomous role for the Nf1/Ras pathway in the regulation of myelin compaction, and a non-cell autonomous role in the regulation of astrocyticendfeet surrounding brain capillaries