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The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection that causes coronavirus disease 2019 (COVID-19) has resulted in a pandemic affecting the most vulnerable in society, triggering a public health crisis and economic collapse around the world. Effective treatments to mitigate this viral infection are needed. Since the eye is a route of virus entrance, we use an in vivo rat model of corneal inflammation as well as human corneal epithelial cells (HCEC) in culture challenged with IFNγ as models of the eye surface to study this issue. We explore ways to block the receptor-binding domain (RBD) of SARS-CoV-2 Spike (S) protein to angiotensin-converting enzyme 2 (ACE2). We found that the lipid mediators, elovanoid (ELV)-N32 or Resolvin D6-isomer (RvD6i) decreased the expression of the ACE2 receptor, furin, and integrins in damaged corneas or IFNγ-stimulated HCEC. There was also a concomitant decrease in the binding of Spike RBD with the lipid treatments. Using RNA-seq analysis, we uncovered that the lipid mediators also attenuated the expression of pro-inflammatoy cytokines participating in hyper-inflammation and senescence programming. Thus, the bioactivity of these lipid mediators will contribute to open therapeutic avenues to counteract virus attachment and entrance to the body.

Cancer cells exhibit dysregulation of critical genes including those involved in lipid biosynthesis, with subsequent defects in metabolism. Here, we show that ELOngation of Very Long chain fatty acids protein 4 (ELOVL4), a rate-limiting enzyme in the biosynthesis of very-long polyunsaturated fatty acids (n-3, ≥28 C), is expressed and transcriptionally repressed by the oncogene MYCN in neuroblastoma cells. In keeping, ELOVL4 positively regulates neuronal differentiation and lipids droplets accumulation in neuroblastoma cells. At the molecular level we found that MYCN binds to the promoter of ELOVL4 in close proximity to the histone deacetylases HDAC1, HDAC2, and the transcription factor Sp1 that can cooperate in the repression of ELOVL4 expression. Accordingly, in vitro differentiation results in an increase of fatty acid with 34 carbons with 6 double bonds (FA34:6); and when MYCN is silenced, FA34:6 metabolite is increased compared with the scrambled. In addition, analysis of large neuroblastoma datasets revealed that ELOVL4 expression is highly expressed in localized clinical stages 1 and 2, and low in high-risk stages 3 and 4. More importantly, high expression of ELOVL4 stratifies a subsets of neuroblastoma patients with good prognosis. Indeed, ELOVL4 expression is a marker of better overall clinical survival also in MYCN not amplified patients and in those with neuroblastoma-associated mutations. In summary, our findings indicate that MYCN, by repressing the expression of ELOVL4 and lipid metabolism, contributes to the progression of neuroblastoma.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection that causes coronavirus disease 2019 (COVID-19) has resulted in a pandemic affecting the most vulnerable in society, triggering a public health crisis and economic tall around the world. Effective treatments to mitigate this virus infection are needed. Since the eye is a route of virus entrance, we use an in vivo rat model of corneal inflammation as well as human corneal epithelial cells in culture challenged with IFNγ to study this issue. We explore ways to block the receptor-binding domain (RBD) of SARS-CoV-2 spike (S) protein to angiotensin-converting enzyme 2 (ACE2). Elovanoid (ELV)-N32 or Resolvin D6-isomer (RvD6i), among the lipid mediators studied, consistently decreased the expression of the ACE2 receptor, furin, and integrins in damaged corneas or IFNγ stimulated human corneal epithelial cells (HCEC). There was also a concomitant decrease in the binding of spike RBD with the lipid treatments. Concurrently, we uncovered that the lipid mediators also attenuated the expression of cytokines that participate in the cytokine storm, hyper-inflammation and senescence programming. Thus, the bioactivity of these lipid mediators will contribute to opening therapeutic avenues for COVID-19 by counteracting virus attachment and entrance to the eye and other cells and the ensuing disruptions of homeostasis.

Neuroprotectin D1 (NPD1), a docosahexaenoic acid (DHA)-derived mediator, induces cell survival in uncompensated oxidative stress (OS), neurodegenerations or ischemic stroke. The molecular principles underlying this protection remain unresolved. We report here that, in retinal pigment epithelial cells, NPD1 induces nuclear translocation and cREL synthesis that, in turn, mediates BIRC3 transcription. NPD1 activates NF-κB by an alternate route to canonical signaling, so the opposing effects of TNFR1 and NPD1 on BIRC3 expression are not due to interaction/s between NF-κB pathways. RelB expression follows a similar pattern as BIRC3, indicating that NPD1 also is required to activate cREL-mediated RelB expression. These results suggest that cREL, which follows a periodic pattern augmented by the lipid mediator, regulates a cluster of NPD1-dependent genes after cREL nuclear translocation. BIRC3 silencing prevents NPD1 induction of survival against OS. Moreover, brain NPD1 biosynthesis and selective neuronal BIRC3 abundance are increased by DHA after experimental ischemic stroke followed by remarkable neurological recovery. Thus, NPD1 bioactivity governs key counter-regulatory gene transcription decisive for retinal and brain neural cell integrity when confronted with potential disruptions of homeostasis.

Ring finger protein 146 (Iduna) facilitates DNA repair and protects against cell death induced by NMDA receptor-mediated glutamate excitotoxicity or by cerebral ischemia. Neuroprotectin D1 (NPD1), a docosahexaenoic acid (DHA)-derived lipid mediator, promotes cell survival under uncompensated oxidative stress (UOS). Our data demonstrate that NPD1 potently upregulates Iduna expression and provides remarkable cell protection against UOS. Iduna, which was increased by the lipid mediator, requires the presence of the poly(ADP-ribose) (PAR) sites. Moreover, astrocytes and neurons in the penumbra display an enhanced abundance of Iduna, followed by remarkable neurological protection when DHA, a precursor of NPD1, is systemically administered 1 h after 2 h of ischemic stroke. These findings provide a conceptual advancement for survival of neural cells undergoing challenges to homeostasis because a lipid mediator, made 'on demand,' modulates the abundance of a critically important protein for cell survival. Fil: Belayev, Ludmila. Louisiana State University Health Sciences Center; Estados Unidos Fil: Mukherjee, Pranab K. Louisiana State University Health Sciences Center; Estados Unidos Fil: Balaszczuk, Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones y Estudio sobre Cultura y Sociedad. Centro de Investigaciones de la Facultad de Psicología - Grupo Vinculado CIPSI; Argentina. Louisiana State University Health Sciences Center; Estados Unidos Fil: Calandria, Jorgelina M. Louisiana State University Health Sciences Center; Estados Unidos Fil: Obenaus, Andre. Loma Linda University Adventist Health Sciences Center; Estados Unidos Fil: Khoutorova, Larissa. Louisiana State University Health Sciences Center; Estados Unidos Fil: Hong, Sung-Ha. Louisiana State University Health Sciences Center; Estados Unidos Fil: Bazan, Nicolas G.. Louisiana State University Health Sciences Center; Estados Unidos

The identification of pathways necessary for photoreceptor and retinal pigment epithelium (RPE) function is critical to uncover therapies for blindness. Here we report the discovery of adiponectin receptor 1 (AdipoR1) as a regulator of these cells' functions. Docosahexaenoic acid (DHA) is avidly retained in photoreceptors, while mechanisms controlling DHA uptake and retention are unknown. Thus, we demonstrate that AdipoR1 ablation results in DHA reduction. In situ hybridization reveals photoreceptor and RPE cell AdipoR1 expression, blunted in AdipoR1(-/-) mice. We also find decreased photoreceptor-specific phosphatidylcholine containing very long-chain polyunsaturated fatty acids and severely attenuated electroretinograms. These changes precede progressive photoreceptor degeneration in AdipoR1(-/-) mice. RPE-rich eyecup cultures from AdipoR1(-/-) reveal impaired DHA uptake. AdipoR1 overexpression in RPE cells enhances DHA uptake, whereas AdipoR1 silencing has the opposite effect. These results establish AdipoR1 as a regulatory switch of DHA uptake, retention, conservation and elongation in photoreceptors and RPE, thus preserving photoreceptor cell integrity.

The identification of pathways necessary for photoreceptor and retinal pigment epithelium (RPE) function is critical to uncover therapies for blindness. Here we report the discovery of adiponectin receptor 1 (AdipoR1) as a regulator of these cells’ functions. Docosahexaenoic acid (DHA) is avidly retained in photoreceptors, while mechanisms controlling DHA uptake and retention are unknown. Thus, we demonstrate that AdipoR1 ablation results in DHA reduction. In situ hybridization reveals photoreceptor and RPE cell AdipoR1 expression, blunted in AdipoR1−/− mice. We also find decreased photoreceptor-specific phosphatidylcholine containing very long-chain polyunsaturated fatty acids and severely attenuated electroretinograms. These changes precede progressive photoreceptor degeneration in AdipoR1−/− mice. RPE-rich eyecup cultures from AdipoR1−/− reveal impaired DHA uptake. AdipoR1 overexpression in RPE cells enhances DHA uptake, whereas AdipoR1 silencing has the opposite effect. These results establish AdipoR1 as a regulatory switch of DHA uptake, retention, conservation and elongation in photoreceptors and RPE, thus preserving photoreceptor cell integrity., Docosahexaenoic acid is a major and important retinal fatty acid that is recruited and retained in the photoreceptor membrane via an unknown mechanism. Here, Rice et al. show that adiponectin receptor 1 is a key molecular switch for docosahexaenoic acid membrane homeostasis and photoreceptor cell function.

Parkinson’s disease (PD) does not manifest clinically until 80 % of striatal dopamine is reduced, thus most neuronal damage takes place before the patient presents clinical symptoms. Therefore, it is important to develop preventive strategies for this disease. In the experimental models of PD, 1-methyl-4-phenylpyridinium ion (MPP+) and rotenone induce toxicity in dopaminergic neurons. Neuroprotectin D1 (NPD1) displays neuroprotection in cells undergoing proteotoxic and oxidative stress. In the present report, we established an in vitro model using a primary neuronal culture from mesencephalic embryonic mouse tissue in which 17–20 % of neurons were TH-positive when differentiated in vitro. NPD1 (100 nM) rescued cells from apoptosis induced by MPP+ and rotenone, and the dendritic arbor of surviving neurons was examined using Sholl analysis. Rotenone, as well as MPP+ and its precursor 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), severely promoted retraction of dendritic arbor distal segments, thus decreasing the maximum branch order reached. On average, NPD1 counteracted the effects of MPP+ on the dendritic arborization, but failed to do so in the rotenone-treated neurons. However, rotenone did decrease the Sholl intersection number from radii 25 to 125 µm, and NPD1 did restore the pattern to control levels. Similarly, NPD1 partially reverted the dendrite retraction caused by MPP+ and MPTP. These results suggest that the apoptosis occurring in mesencephalic TH-positive neurons is not a direct consequence of mitochondrial dysfunction alone and that NPD1 signaling may be counteracting this damage. These findings lay the groundwork for the use of the in vitro model developed for future studies and for the search of specific molecular events that NPD1 targets to prevent early neurodegeneration in PD. Electronic supplementary material The online version of this article (doi:10.1007/s10571-015-0206-6) contains supplementary material, which is available to authorized users.