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Full-Text Articles in Biology

Isoform-Specific Effects Of Apoe On Neurite Outgrowth In Olfactory Epithelium Culture, Aseem Hussain, Minh Luong, Apryl Pooley, Britto P. Nathan Jan 2013

Isoform-Specific Effects Of Apoe On Neurite Outgrowth In Olfactory Epithelium Culture, Aseem Hussain, Minh Luong, Apryl Pooley, Britto P. Nathan

Britto P. Nathan

The apolipoprotein E4 (apoE4) genotype is a major risk factor for developing late-onset Alzheimer’s disease (AD). Inheritance of apoE4 is also associated with impairments in olfactory function in early stages of AD. In this project we examined the effects of the three common isoforms of human apoE (apoE2, apoE3, and apoE4) on neuronal differentiation and neurite outgrowth in explant cultures of mouse olfactory epithelium (OE).


Long-Term Effects Of Estradiol Replacement In The Olfactory System, Britto P. Nathan, Michael Tonsor, Robert G. Struble Sep 2012

Long-Term Effects Of Estradiol Replacement In The Olfactory System, Britto P. Nathan, Michael Tonsor, Robert G. Struble

Britto P. Nathan

Olfactory dysfunction often precedes other clinical symptoms in chronic neurodegenerative diseases like Alzheimer’s and Parkinson’s disease. Estrogen deficiency and apoE genotype are known risk factors in these diseases and these factors also affect olfaction. Therefore we examined the effects of estradiol replacement following ovariectomy on expression of apoE and markers of cell proliferation, neuronal maturation, synaptogenesis and reactive gliosis in the primary olfactory pathway of wild-type (WT) and apoE knockout (KO) mice. Estradiol replacement increased apoE staining in the olfactory nerve and glomerular layers. Estradiol increased astrocyte density and olfactory epithelium (OE) thickness regardless of the genotype. In addition estradiol …


Acute Responses To Estradiol Replacement In The Olfactory System Of Apoe-Deficient And Wild-Type Mice, Britto P. Nathan, Michael Tonsor, Robert G. Struble Jul 2010

Acute Responses To Estradiol Replacement In The Olfactory System Of Apoe-Deficient And Wild-Type Mice, Britto P. Nathan, Michael Tonsor, Robert G. Struble

Britto P. Nathan

Epidemiological studies suggest that estrogen therapy protects against clinical expression of chronic neurological diseases. These beneficial effects of estrogen therapy are highly modified by apolipoprotein E (apoE) through an unknown mechanism. We examined the short-term effects of estradiol replacement in ovariectomized mice on apoE expression and markers for cell proliferation, reactive gliosis, neuronal maturation, and synaptogenesis in the primary olfactory pathway of wild-type (WT) and apoE knockout (KO) mice. Three days of estradiol replacement increased apoE expression in the olfactory nerve and in the glomerular layer. Estradiol treatment also increased cell proliferation, total cell numbers, number of mature neurons in …


Reconstitution Of The Olfactory Epithelium Following Injury In Apoe-Deficient Mice, Britto P. Nathan, Salina Gairhe, Ikemefuna Nwosu, Stephen Clark, Robert G. Struble Jan 2010

Reconstitution Of The Olfactory Epithelium Following Injury In Apoe-Deficient Mice, Britto P. Nathan, Salina Gairhe, Ikemefuna Nwosu, Stephen Clark, Robert G. Struble

Britto P. Nathan

ApoE, a protein component of lipoproteins, is extensively expressed in the primary olfactory pathway. Because apoE has been shown to play a vital role in nerve repair and remodeling, we hypothesized that apoE expression will increase in the injured olfactory epithelium (OE), and that apoE deficiency in apoE knockout (KO) mice will lead to delayed/incomplete reconstitution of the OE following injury. To directly test this hypothesis, we compared OE regeneration in wild-type (WT) and KO mice following injury induced by intranasal irrigation of Triton X-100. OE was collected at 0, 3, 7, 21, 42, and 56 days post lesion. The …


Impact Of Apoe Deficiency During Synaptic Remodeling In The Mouse Olfactory Bulb, Ikemefuna Nwosu, Salina Gairhe, Robert G. Struble, Britto P. Nathan Aug 2008

Impact Of Apoe Deficiency During Synaptic Remodeling In The Mouse Olfactory Bulb, Ikemefuna Nwosu, Salina Gairhe, Robert G. Struble, Britto P. Nathan

Britto P. Nathan

In this study we examined the role of apoE on the rate of synaptic recovery in the olfactory bulb (OB) following olfactory epithelium (OE) lesioning in mice. We used both immunoblotting and immunohistochemical techniques to compare the density of OB synaptophysin (Syn, a synaptic marker) in apoE-gene deficient/knockout (KO) mice and wild-type (WT) mice following OE lesion. We found that the whole bulb concentrations of Syn, measured by immunoblotting, declined sharply following injury in both WT and KO mice during the degenerative phase (3–7 days). After this initial decline, the Syn concentration gradually increased to normal levels by 56 days …


The Distribution Of Apolipoprotein E In Mouse Olfactory Epithelium, Britto P. Nathan, Sreenivas Nannapaneni, Salina Gairhe, Ikemefuna Nwosu, Robert G. Struble Mar 2007

The Distribution Of Apolipoprotein E In Mouse Olfactory Epithelium, Britto P. Nathan, Sreenivas Nannapaneni, Salina Gairhe, Ikemefuna Nwosu, Robert G. Struble

Britto P. Nathan

Previous studies from our laboratory suggest that apolipoprotein (apoE), a lipid transporting protein, facilitates olfactory nerve regeneration. We have shown that apoE is enriched in the olfactory nerve and around the glomeruli of the olfactory bulb (OB). The studies reported herein were undertaken to identify possible sources of apoE in the olfactory epithelium (OE). Immunoblotting results revealed apoE expression in the OE of wild-type (WT) mice, but not in apoE deficient/knockout (KO) mice. Immunohistochemical studies revealed that the perikarya and processes of sustentacular (Sus) cells expressed apoE-like immunoreactivity. Minimal neuronal apoE immunostaining was seen, although apoE was observed in the …