- Anatomic Pathology
Honors & Awards
Young Physician Scientist Award, American Society for Clinical Investigation (ASCI) (2015)
Early Career Investigator, Charleston Conference on Alzheimer Disease (CCAD) (2014)
New Investigator Award in Alzheimer's Disease, American Federation for Aging Research (2012)
Member, Alpha Omega Alpha Honor Medical Society (2005 - present)
Board Certification: Neuropathology, American Board of Pathology (2011)
Board Certification: Anatomic Pathology, American Board of Pathology (2011)
Medical Education:University of Illinois at Chicago College of Medicine Urbana-Cham (2005) IL
University of Illinois at Chicago College of Medicine Urbana-Cham (2004) IL
Fellowship:University of Pittsburgh School of Medicine (2011) PA
Residency:University of Pittsburgh School of Medicine (2008) PA
Board Certification, American Board of Pathology, Neuropathology (2011)
Board Certification, American Board of Pathology, Anatomic Pathology (2011)
B.S., University of Pittsburgh, Neuroscience (1996)
Tumefactive demyelination associated with developmental venous anomaly: Report of two cases
2017; 43: 194-198
We present two cases of tumefactive demyelination (TD) occurring in close association with a developmental venous anomaly (DVA). Our purpose is to describe the association between demyelinating lesions and venous anomalies, as only one case of TD associated with a DVA has been published in the literature. Appropriate recognition of this "do not touch" lesion may avoid invasive and potentially harmful procedures such as biopsy or resection.
View details for DOI 10.1016/j.clinimag.2017.02.012
View details for Web of Science ID 000401298400039
View details for PubMedID 28364723
The CEP19-RABL2 GTPase Complex Binds IFT-B to Initiate Intraflagellar Transport at the Ciliary Base.
Highly conserved intraflagellar transport (IFT) protein complexes direct both the assembly of primary cilia and the trafficking of signaling molecules. IFT complexes initially accumulate at the base of the cilium and periodically enter the cilium, suggesting an as-yet-unidentified mechanism that triggers ciliary entry of IFT complexes. Using affinity-purification and mass spectrometry of interactors of the centrosomal and ciliopathy protein, CEP19, we identify CEP350, FOP, and the RABL2B GTPase as proteins organizing the first known mechanism directing ciliary entry of IFT complexes. We discover that CEP19 is recruited to the ciliary base by the centriolar CEP350/FOP complex and then specifically captures GTP-bound RABL2B, which is activated via its intrinsic nucleotide exchange. Activated RABL2B then captures and releases its single effector, the intraflagellar transport B holocomplex, from the large pool of pre-docked IFT-B complexes, and thus initiates ciliary entry of IFT.
View details for DOI 10.1016/j.devcel.2017.05.016
View details for PubMedID 28625565
Hippocampal phospho-tau/MAPT neuropathology in the fornix in Alzheimer disease: an immunohistochemical autopsy study.
Acta neuropathologica communications
2016; 4 (1): 114-?
Whereas early Alzheimer disease (AD) neuropathology and mild cognitive impairment are relatively common in aging, accurate prediction of patients that will progress to dementia requires new biomarkers. Recently, substantial work has focused on phospho-tau/MAPT (p-MAPT) neuropathology since its regional propagation correlates with the degree of cognitive impairment in AD. Recent diffusion tensor imaging studies in AD suggest that increased diffusion in the fornix secondary to p-MAPT-related axonal injury could serve as a predictive biomarker of the risk of disease progression. However, our knowledge of p-MAPT neuropathology in the fornix is limited. To address this gap in knowledge, we examined p-MAPT neuropathology in the fornix and basal forebrain nuclei via AT8 immunohistochemistry in 39 brain autopsies spanning the spectrum of AD neuropathologic changes. We found that the fornix and its precommissural efferent target nuclei (septum and nucleus accumbens) demonstrated neuronal and thread-like p-MAPT neuropathology only in National Institute on Aging/Alzheimer Association (NIA/AA) stages B2 and B3 of neurofibrillary degeneration, consistent with involvement after (and propagation from) the hippocampal formation. Interestingly, although tau astrogliopathy was frequently observed in the mammillary bodies in stage B2, neuronal tauopathy was not observed in the postcommissural targets (mammillary bodies and anterior thalamic nucleus) until stage B3. Tauopathy in the nucleus basalis of Meynert was strongly correlated with p-MAPT-positive axons in the fornix, suggesting that projections to the hippocampus also likely contribute to fornix tauopathy. Our cross-sectional autopsy findings indicate that the fornix is involved by p-MAPT neuropathology secondary to hippocampal involvement by AD neuropathology. Furthermore, our findings are compatible with the goal of in vivo detection of p-MAPT-related axonal pathology in the fornix in AD as a possible biomarker of p-MAPT progression from the hippocampal formation and underscore a need for additional clinical-radiologic-pathologic correlation studies.
View details for PubMedID 27793193
View details for PubMedCentralID PMC5086039
BECN1/Beclin 1 sorts cell-surface APP/amyloid ß precursor protein for lysosomal degradation.
The regulation of plasma membrane (PM)-localized transmembrane protein/receptor trafficking has critical implications for cell signaling, metabolism and survival. In this study, we investigated the role of BECN1 (Beclin 1) in the degradative trafficking of PM-associated APP (amyloid β precursor protein), whose metabolism to amyloid-β, an essential event in Alzheimer disease, is dependent on divergent PM trafficking pathways. We report a novel interaction between PM-associated APP and BECN1 that recruits macroautophagy/endosomal regulatory proteins PIK3C3 and UVRAG. We found that BECN1 promotes surface APP internalization and sorting predominantly to endosomes and endolysosomes. BECN1 also promotes the targeting of a smaller fraction of internalized APP to LC3-positive phagophores, suggesting a role for BECN1-dependent PM macroautophagy in APP degradation. Furthermore, BECN1 facilitates lysosomal degradation of surface APP and reduces the secretion of APP metabolites (soluble ectodomains, sAPP). The association between APP and BECN1 is dependent on the evolutionarily conserved domain (ECD) of BECN1 (amino acids 267-337). Deletion of a BECN1 ECD subregion (amino acids 285-299) did not impair BECN1- PIK3C3 interaction, PtdIns3K function or macroautophagy, but was sufficient to impair the APP-BECN1 interaction and BECN1's effects on surface APP internalization and degradation, resulting in increased secretion of sAPPs. Interestingly, both the BECN1-APP association and BECN1-dependent APP endocytosis and degradative trafficking were negatively regulated by active AKT. Our results further implicate phosphorylation of the BECN1 Ser295 residue in the inhibition of APP degradation by AKT. Our studies reveal a novel function for BECN1 in the sorting of a plasma membrane protein for endolysosomal and macroautophagic degradation.
View details for PubMedID 27715386
View details for PubMedCentralID PMC5173276
- Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) AUTOPHAGY 2016; 12 (1): 1-222
Histologic Artifacts of Autolytic Muller Cell Foot Process Swelling in Postmortem Examination of Infant Eyes Potential Pitfall in the Evaluation of Traumatic Retinal Hemorrhages
2015; 133 (6): 706-709
Retinal hemorrhages are an important sequela of fatal head trauma. The accurate pathologic diagnosis of retinal hemorrhages has critical implications for determination of the manner of death.We describe an autolytic postmortem histologic artifact of eosinophilic Müller cell foot process swelling that mimics a nerve fiber layer hemorrhage. From April 24, 2012, through November 11, 2014, we conducted postmortem examination of the eyes of 23 infants and children who were referred to our institution for possible nonaccidental head trauma. A focal artifact of Müller cell foot process swelling was identified in most patients (16 of 23) up to 4 years of age. Three infants, all of whom were younger than 3 months, demonstrated diffusely swollen Müller cell foot processes with intensely eosinophilic cytoplasm that mimicked erythrocytes of nerve fiber layer hemorrhages. The difference in the mean age between patients with diffuse eosinophilic artifacts (1.7 months) and patients with only a multifocal, focal, or absent artifact (13.3 months) was 11.6 months (95% CI, 6.5-16.7 months). Glycophorin C immunohistochemical analysis was useful to differentiate this artifact from nerve fiber layer hemorrhage.Our case review demonstrates an artifact of eosinophilic Müller cell foot processes swelling in postmortem examination of young infant eyes, a potential pitfall in the diagnosis of retinal hemorrhages. Our findings have important implications for the diagnosis of retinal hemorrhages in potential cases of nonaccidental head injury.
View details for DOI 10.1001/jamaophthalmol.2015.0493
View details for Web of Science ID 000356044400022
View details for PubMedID 25837496
Neuropathologic analysis of Tyr69His TTR variant meningovascular amyloidosis with dementia.
Acta neuropathologica communications
2015; 3 (1): 43-?
Transthyretin/TTR gene mutations usually cause systemic amyloidotic diseases. Few TTR variants preferentially affect the central nervous system, manifesting as oculoleptomeningeal amyloidosis. Patients with TTR meningovascular amyloidosis often show dementia, however the neuropathologic features of dementia in these cases have not been elucidated. We report the neuropathologic findings from a brain autopsy of a 72-year-old man with the rare Tyr69His (Y69H) TTR gene variant, dementia and ataxia. Severe amyloid deposits were observed in the leptomeninges and in a subpial and subependymal distribution. Mass spectrometry analysis demonstrated that the amyloid deposits were comprised of over 80 % of the variant TTR. TTR was undetectable by mass spectrometry in the neocortex subjacent to the subpial amyloid deposits. Subpial TTR amyloid deposits were associated with brisk superficial reactive gliosis and siderosis in the neocortex and cerebellar cortex. Subependymal TTR amyloid deposits were associated with subjacent myelin pallor in the hippocampal outflow tract structures including the alveus, fimbria and fornix. Phospho-tau immunostains demonstrated transentorhinal-stage neurofibrillary degeneration (Braak stage II) which, in the absence of neocortical amyloid-beta and neuritic plaques, was indicative of primary age-related tauopathy (PART). However, distinctive phospho-tau aggregates were observed subjacent to the subpial TTR amyloid deposits in all regions of the neocortex, including the primary motor and striate cortices, suggesting a potential link between TTR amyloid and neocortical tauopathy. Our report reveals novel insights into the potential neuropathologic substrates of dementia in variant TTR amyloidosis that need to be investigated in larger autopsy series.
View details for DOI 10.1186/s40478-015-0216-0
View details for PubMedID 26156087
View details for PubMedCentralID PMC4496870
Mutant LRRK2 enhances glutamatergic synapse activity and evokes excitotoxic dendrite degeneration.
Biochimica et biophysica acta
2014; 1842 (9): 1596-1603
Mutations in leucine-rich repeat kinase 2 (LRRK2), which are associated with autosomal dominant Parkinson's disease, elicit progressive dendrite degeneration in neurons. We hypothesized that synaptic dysregulation contributes to mutant LRRK2-induced dendritic injury. We performed in vitro whole-cell voltage clamp studies of glutamatergic receptor agonist responses and glutamatergic synaptic activity in cultured rat cortical neurons expressing full-length wild-type and mutant forms of LRRK2. Expression of the pathogenic G2019S or R1441C LRRK2 mutants resulted in larger whole-cell current responses to direct application of AMPA and NMDA receptor agonists. In addition, mutant LRRK2-expressing neurons exhibited an increased frequency of spontaneous miniature excitatory postsynaptic currents (mEPSCs) in conjunction with increased excitatory synapse density as assessed by immunofluorescence for PSD95 and VGLUT1. Mutant LRRK2-expressing neurons showed enhanced vulnerability to acute synaptic glutamate stress. Furthermore, treatment with the NMDA receptor antagonist memantine significantly protected against subsequent losses in dendrite length and branching complexity. These data demonstrate an early association between mutant LRRK2 and increased excitatory synapse activity, implicating an excitotoxic contribution to mutant LRRK2 induced dendrite degeneration.
View details for DOI 10.1016/j.bbadis.2014.05.016
View details for PubMedID 24874075
- Mutant LRRK2 enhances glutamatergic synapse activity and evokes excitotoxic dendrite degeneration. Biochimica et biophysica acta 2014; 1842 (9): 1596-1603
- GA binding protein augments autophagy via transcriptional activation of BECN1-PIK3C3 complex genes AUTOPHAGY 2014; 10 (9): 1622-1636
Tectal pineal cyst in a 1-year-old girl.
2014; 45 (3): 653-656
Glial cysts of the pineal gland can frequently be found in adults and children, but only rarely do they enlarge to become clinically relevant. We report a unique presentation of a pineal cyst in the midbrain tectum of a 16-month-old girl who initially presented with ptosis and strabismus. Preoperative imaging studies and intraoperative findings revealed no continuity between the tectal cyst and the pineal gland proper. We surmise that this tectal pineal cyst may have arisen from duplicated pineal gland tissue.
View details for DOI 10.1016/j.humpath.2013.10.002
View details for PubMedID 24411061
Co-occurrence of a cerebral cavernous malformation and an orbital cavernous hemangioma in a patient with seizures and visual symptoms: Rare crossroads for vascular malformations.
Surgical neurology international
2014; 5: S148-54
Cerebral cavernous malformations (CCMs) are angiographically occult vascular malformations of the central nervous system. As a result of hemorrhage and mass effect, patients may present with focal neurologic deficits, seizures, and other symptoms necessitating treatment. Once symptomatic, most often from hemorrhage, CCMs are treated with microsurgical resection. Orbital cavernous hemangiomas (OCHs) are similar but distinct vascular malformations that present within the orbital cavity. Even though CCMs and OCHs are both marked by dilated endothelial-lined vascular channels, they are infrequently seen in the same patient.We provide a brief overview of the two related pathologies in the context of a patient presenting to our care with concomitant lesions, which were both resected in full without complication.This is the first known report that describes a case of concomitant CCM and OCH and explores the origins of two pathologies that are rarely encountered together in neurosurgical practice. Recognition of disparate symptomatologies is important for properly managing these patients.
View details for DOI 10.4103/2152-7806.134810
View details for PubMedID 25071938
- Occult pigmented ganglioglioma in an adult male with chronic posttraumatic epilepsy. Clinical neuropathology 2013; 32 (3): 192-195