Publications

2019

Chi ZL, Adini A, Birsner A, Bazinet L, Akula J, D’Amato R. PR1P ameliorates neurodegeneration through activation of VEGF signaling pathway and remodeling of the extracellular environment. Neuropharmacology. 2019;148:96–106.
Neurodegenerative diseases affect millions of people worldwide. Optic neuropathies are the most commonly occurring neurodegenerative diseases, characterized by progressive retinal ganglion cell (RGC) degeneration. We recently reported that Prominin-1, a protein found on the surface of stem cells, interacts with VEGF and enhances its activity. VEGF is known to have various protective roles in the nervous system. Subsequently, we have developed a 12-mer peptide derived from Prominin-1, named PR1P, and investigated its effects on neuronal survival of damaged RGCs in a rat model of optic nerve crush (ONC). PR1P prevented RGC apoptosis resulting in improvement of retinal function in the rat ONC model. PR1P treatment significantly increased phosphorylation of ERK and AKT and expression its downstream proteins c-fos and Egr-1 in the retina. Additionally, PR1P beneficially increased the MMP-9/TIMP-1 ratio and promoted glial activation in the retina of ONC rats. Thus, PR1P displayed neuroprotective effects through enhanced VEGF-driven neuronal survival and reconstruction of the extracellular environment in ONC model. Our data indicate that PR1P may be a promising new clinical candidate for the treatment of neurodegenerative diseases.
Madhavan R, Bansal A, Madsen J, Golby A, Tierney T, Eskandar E, Anderson W, Kreiman G. Neural Interactions Underlying Visuomotor Associations in the Human Brain. Cereb Cortex. 2019;29(11):4551–4567.
Rapid and flexible learning during behavioral choices is critical to our daily endeavors and constitutes a hallmark of dynamic reasoning. An important paradigm to examine flexible behavior involves learning new arbitrary associations mapping visual inputs to motor outputs. We conjectured that visuomotor rules are instantiated by translating visual signals into actions through dynamic interactions between visual, frontal and motor cortex. We evaluated the neural representation of such visuomotor rules by performing intracranial field potential recordings in epilepsy subjects during a rule-learning delayed match-to-behavior task. Learning new visuomotor mappings led to the emergence of specific responses associating visual signals with motor outputs in 3 anatomical clusters in frontal, anteroventral temporal and posterior parietal cortex. After learning, mapping selective signals during the delay period showed interactions with visual and motor signals. These observations provide initial steps towards elucidating the dynamic circuits underlying flexible behavior and how communication between subregions of frontal, temporal, and parietal cortex leads to rapid learning of task-relevant choices.
SIGNIFICANCE: This research is significant because, although vision-related quality of life (VRQoL) is improved after vision rehabilitation (VR), patients with certain characteristics respond less positively on VRQoL measures, and this should inform future care. PURPOSE: The purposes of this study were to evaluate how two VRQoL questionnaires compare in measuring change in patient-reported outcomes after VR and to determine if patient characteristics or occupational therapy (OT) predict higher scores after rehabilitation. METHODS: In a prospective clinical cohort study, 109 patients with low vision completed the Impact of Vision Impairment (IVI) and the National Eye Institute Visual Functioning Questionnaire (NEI VFQ-25) before and after VR. Comprehensive VR included consultation with an ophthalmologist and OT if required. The relationships of six baseline characteristics (age, sex, visual acuity, contrast sensitivity, field loss, diagnosis) and OT were assessed with VRQoL scores using multivariable logistic regression. RESULTS: The mean (SD) age was 68.5 (19.2) years, and 61 (56%) were female. After rehabilitation, increases in scores were observed in all IVI subscales (reading [P < .001], mobility [P = .002], well-being [P = .0003]) and all NEI VFQ-25 subscales (functional [P = .01], socioemotional [P = .003]). Those who were referred to OT but did not attend and those who had hemianopia/field loss were less likely to have higher VRQoL in IVI mobility and well-being. Those attending OT for more than 3 hours were less likely to have better scores in emotional NEI VFQ. Men were less likely to have increased scores in functional and emotional NEI VFQ, whereas those with diagnoses of nonmacular diseases had higher odds of having increased scores on the emotional NEI VFQ (all, P < .05). CONCLUSION: Both the IVI and the NEI VFQ-25 detected change in patients' VRQoL after rehabilitation. Most of the patient characteristics we considered predicted a lower likelihood of increased scores in VRQoL.
Tiedemann D, Mouhammad Z, Utheim T, Dartt DA, Heegaard S, Petrovski G, Kolko M. Conjunctival Goblet Cells, the Overlooked Cells in Glaucoma Treatment. J Glaucoma. 2019;28(4):325–333.
Glaucoma is the leading cause of irreversible blindness worldwide. Although no definitive cure exists, lowering of the intraocular pressure decreases the rate of progression in the majority of patients with glaucoma. Antiglaucomatous treatment modalities consist predominantly of chronic use of eye drops. It has become increasingly evident that long-term exposure to eye drops has a significant impact on the ocular surface, and thereby on patient compliance and quality of life. Maintenance of the ocular surface is highly dependent on a stable tear film. Conjunctival goblet cells (GCs) of the ocular surface play an important role in providing the innermost mucin layer of the tear film and are essential for maintaining the ocular surface homeostasis. Recent studies have reported severe side effects of antiglaucomatous drops on GCs. In particular, a preservative containing antiglaucomatous drops have been shown to affect the viability and functions of the GCs. Furthermore, GC density has been suggested as a potential predictor of surgical outcome after filtration surgery. The present review provides an overview of the current literature on the impact of antiglaucomatous eye drops on GCs as well as the impact on the ocular surface. Moreover, the existing evidence of a possible association between GC density and glaucoma filtration surgery outcome is summarized. We conclude that prostaglandin analogs spare the conjunctival GCs more compared with other antiglaucomatous drops and that GCs may be a good predictor of surgical outcome after filtration surgery. Overall, given the multiple functions of GCs in the ocular surface homeostasis, dedicated strategies should be adopted to preserve this cell population during the course of glaucoma.
Adil MY, Xiao J, Olafsson J, Chen X, Lagali N, Ræder S, Utheim Ø, Dartt DA, Utheim T. Meibomian Gland Morphology Is a Sensitive Early Indicator of Meibomian Gland Dysfunction. Am J Ophthalmol. 2019;200:16–25.
PURPOSE: To investigate the relationship between meibomian gland (MG) morphology and clinical dry eye tests in patients with meibomian gland dysfunction (MGD). DESIGN: Cross-sectional study. SUBJECTS: Total 538 MGD patients and 21 healthy controls. METHODS: MG loss on meibography images of upper (UL) and lower lids (LL) was graded on a scale of 0 (lowest degree of MG loss) to 3. MG length, thickness, and interglandular space in the UL were measured. Clinical tests included meibum expression and quality, tear film break-up time, ocular staining, osmolarity, Schirmer I, blink interval timing, and Ocular Surface Disease Index (OSDI) questionnaire. RESULTS: Mean UL and LL meibogrades were significantly higher in MGD patients compared to controls (P < .001 for UL and LL). The sensitivity and specificity of the meibograde as a diagnostic parameter for MGD was 96.7% and 85%, respectively. Schirmer I was significantly increased in MGD patients with meibograde 1 compared to patients with meibograde 0, 2, and 3 in the UL (P < .05). MG thickness increased with higher meibograde (P < .001). MG morphology correlated significantly but weakly with several clinical parameters (P < .05). OSDI did not correlate with any MG morphologic parameter. CONCLUSIONS: Grading of MG loss using meibograde effectively diagnoses MGD. Compensatory mechanisms such as increased aqueous tear production and dilation of MGs make early detection of MGD difficult by standard clinical measures of dry eye, whereas morphologic analysis of MGs reveals an early stage of MGD, and therefore represents a complementary clinical parameter with diagnostic potential.
Hård AL, Nilsson A, Lund AM, Hansen-Pupp I, Smith L, Hellström A. Review shows that donor milk does not promote the growth and development of preterm infants as well as maternal milk. Acta Paediatr. 2019;108(6):998–1007.
AIM: This nonsystematic review examined differences in the composition of raw maternal breastmilk and pasteurised donor milk and possible health effects on preterm infants. METHODS: We searched PubMed up to July 2018 for studies published in English that focused on four comparisons as follows: raw maternal milk versus donor milk, human milk before and after Holder pasteurisation, milk from mothers who delivered preterm and at term and milk collected during early and late lactation. We also searched for possible effects of the milk components, as well as the effects of maternal and donor milk on preterm infants' health. RESULTS: Raw maternal milk contained factors involved in antioxidant and anti-inflammatory defence, gut microbiome establishment and the maturation of immune defences, food tolerability and metabolism. Many of these factors were reduced or abolished in processed donor milk. Both maternal milk and donor milk have been associated with a reduced incidence of necrotising enterocolitis. High-dose feeding with maternal milk during the neonatal period reportedly reduced the risk of other morbidities and promoted growth and neurodevelopment. CONCLUSION: Many of the components in raw maternal breastmilk were lacking in pasteurised donor milk, which was inferior in promoting the growth and development of very preterm infants.
PURPOSE: To identify interactions of the epidermal growth factor receptor (EGFR) with the pro-resolving mediator receptors for RvD1 and RvE1 to stimulate an increase in intracellular [Ca] ([Ca]) and mucin secretion from cultured human and rat conjunctival goblet cells. METHODS: Goblet cells from human and rat conjunctiva were grown in culture using RPMI media. Cultured goblet cells were pre-incubated with inhibitors, and then stimulated with RvD1, RvE1, EGF or the cholinergic agonist carbachol (Cch). Increase in [Ca] was measured using fura-2/AM. Goblet cell secretion was measured using an enzyme-linked lectin assay with UEA-1. Western blot analysis was performed with antibodies against AKT and ERK 1/2. RESULTS: In cultured human conjunctival goblet cells RvE1 -stimulated an increase in [Ca]. RvD1-, but not the RvE1-, stimulated increase in [Ca] and mucin secretion was blocked by the EGFR inhibitor AG1478 and siRNA for the EGFR. RvD1-, but not RvE1-stimulated an increase in [Ca] that was also inhibited by TAPI-1, an inhibitor of the matrix metalloprotease ADAM 17. Inhibition of the EGFR also blocked RvD1-stimulated increase in AKT activity and both RvD1-and RvE1-stimulated increase in ERK 1/2 activity. Pretreatment with either RvD1 or RvE1 did not block the EGFR-stimulated increase in [Ca]. CONCLUSIONS: We conclude that in cultured rat and human conjunctival goblet cells, RvD1 activates the EGFR, increases [Ca], activates AKT and ERK1/2 to stimulate mucin secretion. RvE1 does not transactivate the EGFR to increase [Ca] and stimulate mucin secretion, but does interact with the receptor to increase ERK 1/2 activity.
Lahola-Chomiak A, Footz T, Nguyen-Phuoc K, Neil G, Fan BJ, Allen K, Greenfield D, Parrish R, Linkroum K, Pasquale L, Leonhardt R, Ritch R, Javadiyan S, Craig J, Allison, Lehmann O, Walter M, Wiggs J. Non-Synonymous variants in premelanosome protein (PMEL) cause ocular pigment dispersion and pigmentary glaucoma. Hum Mol Genet. 2019;28(8):1298–1311.
Pigmentary glaucoma (PG) is a common glaucoma subtype that results from release of pigment from the iris, called pigment dispersion syndrome (PDS), and its deposition throughout the anterior chamber of the eye. Although PG has a substantial heritable component, no causative genes have yet been identified. We used whole exome sequencing of two independent pedigrees to identify two premelanosome protein (PMEL) variants associated with heritable PDS/PG. PMEL encodes a key component of the melanosome, the organelle essential for melanin synthesis, storage and transport. Targeted screening of PMEL in three independent cohorts (n = 394) identified seven additional PDS/PG-associated non-synonymous variants. Five of the nine variants exhibited defective processing of the PMEL protein. In addition, analysis of PDS/PG-associated PMEL variants expressed in HeLa cells revealed structural changes to pseudomelanosomes indicating altered amyloid fibril formation in five of the nine variants. Introduction of 11-base pair deletions to the homologous pmela in zebrafish by the clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 method caused profound pigmentation defects and enlarged anterior segments in the eye, further supporting PMEL's role in ocular pigmentation and function. Taken together, these data support a model in which missense PMEL variants represent dominant negative mutations that impair the ability of PMEL to form functional amyloid fibrils. While PMEL mutations have previously been shown to cause pigmentation and ocular defects in animals, this research is the first report of mutations in PMEL causing human disease.