New Insights Into Pentosan Polysulfate Maculopathy.

BACKGROUND AND OBJECTIVE: To provide new insights into toxic maculopathy secondary to pentosan polysulfate (PPS) utilizing multimodal testing. PATIENTS AND METHODS: Retrospective case-series of four patients from two academic centers evaluated with multimodal imaging, electrophysiology, dark adaptometry (DA), and genetic testing. RESULTS: Median age was 58 years, exposure to PPS was 18.5 years, and cumulative dose of was 2,025 grams. Seven of eight eyes had visual acuity of 20/40 or better. Optical coherence tomography (OCT) angiography demonstrated increased choriocapillaris flow voids (54.25%) in cases compared to controls (13.2%). Two subjects had abnormal foveal avascular zone configurations. Two subjects demonstrated collapse of the retinal pigment epithelium nodular excrescences and progressive retinal thinning over 4 to 5 years on OCT. Electrophysiology was normal (3/3 patients), but DA was delayed (2/2 patients). CONCLUSIONS: The authors describe novel findings of PPS maculopathy, including flow voids in the choriocapillaris. Progressive retinal thinning may suggest a secondary retinal effect. These findings may improve understanding of the pathophysiology. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:13-22.].

Mass spectrometry proteomics reveals a function for mammalian CALCOCO1 in MTOR-regulated selective autophagy.

Macroautophagy/autophagy is suppressed by MTOR (mechanistic target of rapamycin kinase) and is an anticancer target under active investigation. Yet, MTOR-regulated autophagy remains incompletely mapped. We used proteomic profiling to identify proteins in the MTOR-autophagy axis. Wild-type (WT) mouse cell lines and cell lines lacking individual autophagy genes (Atg5 or Ulk1/Ulk2) were treated with an MTOR inhibitor to induce autophagy and cultured in media with either glucose or galactose. Mass spectrometry proteome profiling revealed an elevation of known autophagy proteins and candidates for new autophagy components, including CALCOCO1 (calcium binding and coiled-coil domain protein 1). We show that CALCOCO1 physically interacts with MAP1LC3C, a key protein in the machinery of autophagy. Genetic deletion of CALCOCO1 disrupted autophagy of the endoplasmic reticulum (reticulophagy). Together, these results reveal a role for CALCOCO1 in MTOR-regulated selective autophagy. More generally, the resource generated by this work provides a foundation for establishing links between the MTOR-autophagy axis and proteins not previously linked to this pathway. Abbreviations: ATG: autophagy-related; CALCOCO1: calcium binding and coiled-coil domain protein 1; CALCOCO2/NDP52: calcium binding and coiled-coil domain protein 2; CLIR: MAP1LC3C-interacting region; CQ: chloroquine; KO: knockout; LIR: MAP1LC3-interacting region; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MEF: mouse embryonic fibroblast; MLN: MLN0128 ATP-competitive MTOR kinase inhibitor; MTOR: mechanistic target of rapamycin kinase; reticulophagy: selective autophagy of the endoplasmic reticulum; TAX1BP1/CALCOCO3: TAX1 binding protein 1; ULK: unc 51-like autophagy activating kinase; WT: wild-type.