Sodium selenite

Jurkat, SupT1 and HEK293T cells lines used in this study were obtained from ATCC. TZM-bl cells were obtained from NIH AIDS Reagent program (Manassas, VA, USA). Fresh blood samples were provided by Etablissement francais du sang (EFS) de Lyon. Cell culture media and supplements, NuPAGE 4–12% bis–Tris polyacrylamide gels, MOPS and MES SDS running buffer, Dynabeads Human T-Activator CD3/CD28 were purchased from Life Technologies (ThermoFisher Scientific, Waltham, MA, USA). Fetal calf serum (FCS), sodium selenite, synthetic oligonucleotides, Percoll, Ficoll, t-BHP, NADPH, thioredoxin, L-GSH, glutathione reductase, DTNB, sucrose, DMSO, EDTA, Triton X100, glycerol and DTT were purchased from Merck (Darmstadt, Germany). Interleukin2 was from Eurobio Scientific (Les Ulis, France). The luciferase assay reagent was purchased from Promega (Charbonnières, France). The microplate readers FLUOSTAR OPTIMA and LUMISTAR OPTIMA were from BMG Labtech (Champigny-sur-Marne, France). The list of antibodies used in this study is given in Table S3. The plasmid pNL4.3 was obtained from the NIH AIDS Reagent program.

A Sartorius arium^® pro system was used to produce ultrapure water (18.2 MΩ·cm). A Qiagen Tissue Ruptor II was used to homogenize the plant samples. Macerozyme R-10 derived from Rhizupus sp. and Proteinase K were used for plant digestion. They were purchased from GeneON and bioWorld, respectively. For the buffer preparation, disodium hydrogen citrate and citric acid were purchase from Sigma-Aldrich. Dialysis membrane Spectra/Por^® 3 with a MWCO of 3.5 kDa and the corresponding closures were purchased from Fisher Scientific.
For the plant growth, a hydroponic system by growland was used. Hoagland solution was prepared from a salt base that was purchased from Biozol. Sodium selenite to spike the growth solution and formalin solution to surface sterilize the seeds were purchased from Merck. Ethanol 96% that was used during the dialysis was purchased from Sigma-Aldrich.
A NexION 350D sp-ICP-MS by Perkin Elmer (Waltham, MA, USA) was used for the analysis. It was equipped with a quartz cyclonic spray chamber and a glass nebulizer (Ar 1.0 SLPM @ 43 psi). The peristaltic pump tubing with flared ends and an inner diameter of 0.38 mm was made of polyvinyl chloride.
Polypropylene tubes with a volume of 50 mL were purchased from Sarstedt AG & Co.KG (Nümbrecht, Germany) and tubes with a volume of 15 mL were purchased from Cellstar.

The mouse OPC cell line Oli-Neu was provided by Jaqueline Trotter (University of Mainz, Mainz, Germany). Cells were grown in T75 cell culture flasks (Thermo Fisher Scientific) using the SATO medium containing Dulbecco’s modified Eagle’s medium (DMEM; Thermo Fisher Scientific) supplemented with 2% heat-inactivated horse serum (Themo Fisher Scientific), 5 µg/mL insulin (Merck, Darmstadt, Germany), 1% penicillin/streptomycin (10,000 U/mL) (Thermo Fisher Scientific), 1% N2 supplement (Thermo Fisher Scientific), 5 ng/mL sodium selenite (Merck), 25 µg/mL gentamicin (Merck, Darmstadt, Germany), 400 nM 3,3′,5-triiodo-L-thyronine (T3) (Merck), and 520 nM L-thyroxine (T4) (Merck). Cells were maintained at 37 °C and 5% CO₂ and passaged when a confluency of 70–80% was reached. All cell culture materials were coated overnight at 37 °C with 0.0001% poly-ornithine (PORN) (Merck) solution.

Oligodendrocyte cell line Oli-neu [39 (link)] was kindly provided by Dr. Patrizia Rosa (CNR-Institute of Neuroscience, Milan) on behalf of Dr. Jacqueline Trotter (University of Mainz, Mainz, Germany). Cells were cultured at 37° C at 5% CO₂ on high molecular weight poly-L-lysine (Merck) coated flasks in SATO medium, prepared by adding the following reagents to high-glucose DMEM (Gibco) according to [40 (link)]: 23.8 µM NaHCO₃ (Merck), 1.25 mM Apo-transferrin (Merck), 1.72 µM Insulin (Merck), 0.1 mM Putrescine (Merck), 0.2 µM Progesterone (Merck), 0.5 mM Triiodo-L-Thyronine (Merck), 0.22 µM Sodium selenite (Merck), 0.5 µM L-Thyroxine (Merck), 52.3 µM Gentamicin (Thermo Fisher Scientific), Horse Serum 1% (Gibco). The culture medium was replaced every 48 h during expansion. Cells were detached by using 0.01% trypsin–EDTA at 60–70% confluency for further expansion or plating. The differentiation into mature oligodendroglial cells was induced by treating Oli-neu cells with 1 mM dibutyryl-cyclic AMP (dbcAMP, Merck) for up to 72 h. Conduritol B epoxide (CBE, Merck) was added in the medium at a concentration of 10 µM to inhibit β-glucocerebrosidase activity. In some experiments cells were plated on glass coverslips for imaging and plastic wells for RNA and protein extraction.

Silver nitrate (AgNO₃), ascorbic acid, sodium selenite (Na₂SeO₃), trichloroacetic acid (TCA), sodium carbonate, 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), phosphate-buffered saline (PBS), and gallic acid were supplied by Merck (Darmstadt, Germany). Folin-Ciocalteau reagent, 2,2-diphenyl-1-picrylhydrazyl (DPPH), and potassium ferricyanide, iron (III) chloride were obtained from Sigma Aldrich Chemical Co. (St Louis, MO, USA). Eagle’s Minimum Essential Medium (EMEM), fetal bovine serum (FBS), trypsin-versene, and antibiotics (Penicillin (5000 units/mL)/Streptomycin (5000 µg/mL)) were purchased from Lonza Bio-Whittaker (Verviers, Belgium). Ocimum tenuiflorum was collected within the province of KwaZulu-Natal, South Africa, and identified at the Department of Botany, University of KwaZulu-Natal. A voucher specimen (K. Olofinsan and F. Olawale 2) was deposited in the Ward Herbarium of the university. The breast adenocarcinoma (MCF-7) and embryonic kidney (HEK293) cells were obtained from the ATCC, Manassas, VA, USA. Sterile plasticware for cell culture was purchased from Corning Inc. (New York, NY, USA). Ultrapure (18 MOhm) water (Millipore, France) was used throughout.

Sodium selenite (Merck Company, Germany, 99.9% pure) was used to induce cataracts in rats. Then, 1% tropicamide ophthalmic solution and 2.5% phenylephrine were used to dilate the pupil of the eye in preparation for the slit-lamp examination. Ketamine 10% injection vial, xylazine 2% injection vial (Alfasan, Netherlands), sodium chloride 0.9%, and Liposic® ophthalmic gel (Dr. Gerhard Mann Chem.-Pharm, Germany) were used.