Journal: Nature metabolism
Article Title: CD38 ecto-enzyme in immune cells is induced during aging regulating NAD + and NMN levels
doi: 10.1038/s42255-020-00298-z
Figure Lengend Snippet: ( a ) Relative mRNA expression of Nampt and Cd157 after treatment of BMDMs of WT and CD38 KO mice with and without 100 ng/mL LPS for 24 hours. Expression, assessed by qRT-PCR, is relative to Ctrl WT (n=4 biologically independent samples). ( b-g ) Characterization of the mouse anti-CD38 antibodies used in this study. ( b ) Schematic representation of a human heavy chain-only antibody (UniAbs). ( c ) Workflow to discover CD38-specific UniAbs. Antibodies were derived from transgenic rats, called UniRats that produce heavy-chain antibodies with fully human V H domains (UniAbs) in response to an antigen challenge. ( d ) Development of UniRat transgenic animals. ( e ) Protein and cell-based screens to discover anti-CD38 UniAbs. ( f ) Graph showing the binding of FITC-labeled Ab68 to freshly isolated mouse spleen cells (n=3 biologically independent samples). ( g ) Effect of Ab68 on the rate of CD38 hydrolase activity at different concentrations of substrate (left, n=8; except for no e-NAD where n=4 biologically independent samples and respective Lineweaver-Burk plots (right, n=6 biologically independent samples). ( h ) Table shows the binding affinities (KD) of anti-mouse CD38 antibodies Ab68 and Ab69 and a mouse control antibody OKT3. NB=No Binding. ( i ) Apoptosis of CHO cells stably transfected with mouse CD38 after incubation with antibodies Ab68, Ab69, and NIMR-5 for 24 hours (n=2 samples per concentration). ( j ) Cell viability of WT macrophages treated with LPS (100 ng/mL), with or without Ab68 or Ab69 (5 μg/mL) for 24 hours (n=4 except for LPS+Ab69 where n=3 biologically independent samples). ( k ) Graph shows the internalization of Ab68 compared to control antibody NIMR-5 after 45 minutes and 1.5 hours. ( l ) NAD + levels in AML 12 treated with 200 μM NMN in the presence or absence of LPS (100 ng/mL), Ab68 (5 μg/mL), and 78c (0.5 μM). LPS was given for 18 hours, then Ab68 was added, and 3 hours later NMN was added. Cells were collected 20 hours after NMN was added. NAD + levels were relative to control (Ctrl) (n=4 biologically independent samples). ( m ) NAD + levels in AML 12 cells cocultured with macrophages from CD38 KO mice. LPS was given for 18 hours to the macrophages, then NMN or NR (200 μM) were added for 3 hours. Next, macrophages were incubated with AMLs, and AML cells were collected 20 hours later. NAD + levels were relative to control (Ctrl) (n=4 biologically independent samples). ( n ) NAD + levels in AML 12 cocultured with macrophages. Macrophages were treated with 200 μM NA in the presence or absence of LPS (100 ng/mL), and Ab68 (5 μg/mL). LPS was given for 18 hours, then Ab68 was added, and 3 hours later nicotinic acid (NA) was added to the macrophages. Three hours after addition of NA, macrophages were incubated with AML cells. AML cells were collected 20 hours later and NAD + levels were calculated relative to control (Ctrl) (n=5 biologically independent samples). ( o ) Macrophages were incubated with conditioned media from senescent (CM-SEN) and non-senescent (CM-NS) mouse pre-adipocytes, and with LPS and without (Ctrl) for 20 hours. Cd38 mRNA expression (CM-NS and CM-SEN n=5; Ctrl and LPS n=4 biologically independent samples), CD38 activity (n=5 biologically independent samples), and NAD + levels (n=6 biologically independent samples) were measured in the macrophages. Samples from cells incubated with CM-SEN, were calculated relative to cells incubated with CM-NS. Samples from cells treated with LPS, were calculated relative to vehicle-treated cells (Ctrl). Data are mean ± SEM, analyzed by unpaired two-sided t -test, NS= non-significant.
Article Snippet: In brief, lymph nodes of 6 UniRats immunized with recombinant murine CD38 protein (R&D Systems) were isolated, washed, and cell pellets frozen.
Techniques: Expressing, Quantitative RT-PCR, Derivative Assay, Transgenic Assay, Binding Assay, Labeling, Isolation, Activity Assay, Stable Transfection, Transfection, Incubation, Concentration Assay