Target deconvolution of HDAC pharmacopoeia reveals MBLAC2 as common off-target.

Drugs that target histone deacetylase (HDAC) entered the pharmacopoeia in the 2000s. However, some enigmatic phenotypes suggest off-target engagement. Here, we developed a quantitative chemical proteomics assay using immobilized HDAC inhibitors and mass spectrometry that we deployed to establish the target landscape of 53 drugs. The assay covers 9 of the 11 human zinc-dependent HDACs, questions the reported selectivity of some widely-used molecules (notably for HDAC6) and delineates how the composition of HDAC complexes influences drug potency. Unexpectedly, metallo-ß-lactamase domain-containing protein 2 (MBLAC2) featured as a frequent off-target of hydroxamate drugs. This poorly characterized palmitoyl-CoA hydrolase is inhibited by 24 HDAC inhibitors at low nanomolar potency. MBLAC2 enzymatic inhibition and knockdown led to the accumulation of extracellular vesicles. Given the importance of extracellular vesicle biology in neurological diseases and cancer, this HDAC-independent drug effect may qualify MBLAC2 as a target for drug discovery.

Role of wide-field autofluorescence imaging and scanning laser ophthalmoscopy in differentiation of choroidal pigmented lesions.

AIM: To evaluate the diagnostic properties of wide-field fundus autofluorescence (FAF) scanning laser ophthalmoscope (SLO) imaging for differentiating choroidal pigmented lesions. METHODS: A consecutive series of 139 patients were included, 101 had established choroidal melanoma with 13 untreated lesions and 98 treated with radiotherapy. Thirty-eight had choroidal nevi. All patients underwent a full ophthalmological examination, undilated wide-field imaging, FAF and standardized US examination. FAF images and imaging characteristics from SLO were correlated with the structural findings in the two patient groups. RESULTS: Mean FAF intensity of melanomas was significantly lower than the FAF of choroidal nevi. Only 1 out of 38 included eyes with nevi touched the optic disc compared to 31 out of 101 eyes with melanomas. In 18 out of 101 melanomas subretinal fluid was seen at the pigmented lesion compared to none seen in eyes with confirmed choroidal nevi. In "green laser separation", a trend towards more mixed FAF appearance of melanomas compared to nevi was observed. The mean maximal and minimal transverse and longitudinal diameters of melanomas were significantly higher than those of nevi. CONCLUSION: Wide-field SLO and FAF imaging may be an appropriate non-invasive diagnostic screening tool to differentiate benign from malign pigmented choroidal lesions.

Systematic analysis of wide-field fundus autofluorescence (FAF) imaging in posterior uveitis.

PURPOSE: To evaluate wide-field fundus autofluorescence (FAF) in patients with uveitis with retinal or chorioretinal involvement. MATERIALS AND METHODS: We included 78 study eyes in this prospective study. Best-corrected visual acuity, a full clinical examination, wide-field green-light FAF and composite color, green and red laser separation fundus imaging with Optomap SLO were performed. In a systematic analysis, the number, extension and margins of central and peripheral retinal or chorioretinal alterations, scars and infiltrates in infectious and non-infectious uveitic study eyes were evaluated. Wide-field FAF and color fundus imaging results were compared regarding their diagnostic properties. RESULTS: Nine out of 78 study eyes were diagnosed with infectious, 69 cases with non-infectious uveitis. Six infectious uveitic study eyes had changes of the peripheral fundus compared with 48 of 69 non-infectious uveitic eyes. In 33 (infectious versus non-infectious: 4 versus 29) cases, wide-field FAF images revealed more retinal or chorioretinal alterations or pathologies with a farther extended demarcation than wide-field composite color fundus imaging. Eleven out of 69 non-infectious study eyes were diagnosed with vasculitis which could be more precisely evaluated with wide-field FAF than wide-field composite color, green or red light filtered fundus imaging. CONCLUSIONS: Non-invasive wide-field FAF detects more retinal or chorioretinal involvement in patients with posterior uveitis than seen in color imaging and thus is useful in diagnosis and follow-up of uveitic patients.

Peripheral fundus autofluorescence is increased in age-related macular degeneration.

PURPOSE: To evaluate peripheral fundus autofluorescence (FAF) in patients with AMD. METHODS: A consecutive series of 71 normal eyes, 71 eyes with neovascular AMD having received anti-VEGF treatment, and 43 eyes with untreated AMD were investigated. In all subjects, wide-field FAF imaging was performed, applying a wide-field scanning laser ophthalmoscope. FAF was quantified by image analysis software after defining peripheral and perifoveal central measurement zones with a grid scheme; age correction was performed by regression model. RESULTS: Fundus autofluorescence increased with age not only in the perifoveal retinal area, but also in the retinal periphery. For age-corrected measurements, peripheral FAF was significantly increased for both, treated and untreated AMD groups compared with normal subjects. No significant difference was observed in peripheral FAF between AMD eyes having received anti-VEGF treatment and those without treatment. Age-corrected normal FAF in the retinal center differed significantly from the anti-VEGF-treated group (P < 0.01), but not the untreated AMD group. Age-corrected peripheral FAF irregularity, defined as the standard deviation in the measurement field, was significantly increased in both AMD groups compared with normal subjects. CONCLUSIONS: Detection of peripheral in addition to central FAF may provide additional information potentially helpful to detect and monitor the development of AMD. No differences in autofluorescence were observed in the retinal periphery between anti-VEGF-treated and untreated eyes.

Wide-field fundus autofluorescence corresponds to visual fields in chorioretinitis patients.

BACKGROUND AND OBJECTIVES: Detection of peripheral fundus autofluorescence (FAF) using conventional scanning laser ophthalmoscopes (SLOs) is difficult and requires pupil dilation. Here we evaluated the diagnostic properties of wide-field FAF detected by a two-laser wavelength wide-field SLO in uveitis patients. STUDY DESIGN/MATERIALS AND METHODS: Observational case series of four patients suffering from different types of posterior uveitis/chorioretinitis. Wide-field FAF images were compared to visual fields. Panretinal FAF was detected by a newly developed SLO, which allows FAF imaging of up to 200° of the retina in one scan without the need for pupil dilation. Visual fields were obtained by Goldmann manual perimetry. RESULTS: Findings from wide-field FAF imaging showed correspondence to visual field defects in all cases. CONCLUSION: Wide-field FAF allowed the detection of visual field defect-related alterations of the retinal pigment epithelium in all four uveitis cases.

Choroidal pigmented lesions imaged by ultra-wide-field scanning laser ophthalmoscopy with two laser wavelengths (Optomap).

PURPOSE: Clinical differentiation of choroidal pigmented lesions is sometimes difficult. Choroidal melanoma is the most prevalent primary neoplasia among malignant ocular tumors, and metastasis often occurs before the primary tumor is diagnosed. Therefore, early detection is essential. We investigated the imaging properties of clinically diagnosed melanocytic choroidal tumors using a nonmydriatic ultra-wide-field scanning laser ophthalmoscope (SLO) with two laser wavelengths to distinguish benign from malignant lesions. Repeated standardized ultrasound (US) evaluation provided reference standard. METHODS: In a consecutive series of 49 patients with clinically diagnosed melanocytic choroidal tumors in one eye, 29 had established melanoma (defined by proven growth on repeated US follow-up) and 20 had nevi (defined by no malignancy according to clinical, US, and growth characteristics for at least 2 years). All patients underwent clinical examination, undilated Optomap((R)) (Optos PLC, Dunfermline, Fife, Scotland, UK) imaging, standardized US examination, and standard retinal photography. Measurements of the tumor base using the Optomap software were compared with US B-scan measurements. Imaging characteristics from the SLO images were correlated with the structural findings in the two patient groups. RESULTS: Measurements of tumor base correlated well between SLO and US with r = 0.61 (T-direction) and r = 0.51 (L-direction). On SLO imaging, typical malignant lesions appeared dark on the red laser channel and bright on the green laser channel. Based on those simple binary characteristics, a sensitivity of 76% at a specificity of 70% was obtained for a correct classification of lesions. When analogous to clinical examination lesion size, margin touching the optic disc, and existence of subretinal fluid were additionally considered, 90% sensitivity at 82% specificity was obtained. CONCLUSIONS: In this first, limited series, nonmydriatic SLO imaging with two laser wavelengths permitted to differentiate malignant ocular tumors from nonmalignant lesions with high diagnostic accuracy. Additional parameters may further enhance diagnostic properties, but larger patient series are required to validate our findings and prove the diagnostic properties.