Fig 2: The role of ARG2 overexpression in NP cells. (A) The effect of ARG2 overexpression on the protein levels of ARG2, MMP13, aggrecan, Bcl2, Bax, COX2, and P21 in NPCs after the treatment of IL-1β. (B) The mRNA level of ARG2 in ARG2-overexpressed NPCs. (C–I) Quantitative analysis of western blotting results. (J,K) Supernatants of TNFα and IL-1β were tested with ELISA. (L,M) The ROS products was increased by ARG2 overexpression followed by treatment of IL-1β (Scale bar: 100 μm). Data are represented as the mean ± SD. Two-group comparisons were analyzed by Student’s t-test. Significant differences between the treatment and control groups are indicated as *P < 0.05, **P < 0.01, and ***P < 0.001, n = 3.

Fig 3: The effect of siRNA-ARG2 on oxidative stress and inflammatory response in NP cells. (A,B) The level of reactive oxygen species (ROS) induced by IL-1β was significantly reduced by ARG2 silencing (Scale bar: 100 μm). (C–G) The effect of downregulation of ARG2 on the levels of proinflammatory factors induced by IL-1β. (H,I) ELISA results detected the level of IL-6 and TNF-α. Data are represented as the mean ± SD. Two-group comparisons were analyzed by Student’s t-test. Significant differences between the treatment and control groups are indicated as *P < 0.05, **P < 0.01, and ***P < 0.001, n = 3.

Fig 4: Arginase II (ARG2) expression is upregulated in intervertebral disc degeneration (IDD) tissues. (A) The flow diagram of this study. (B) Representative T2 signal MRI images and immunohistochemistry results (Scale bar: 100 μm) of each group. (C) Immunohistochemical results were analyzed by semiquantitative analysis. (D) The protein expression of ARG2 in nucleus pulposus tissues in each group was measured by western blotting. (E) The western blotting results were analyzed by semiquantitative analysis. (F) The mRNA level of ARG2 in the in nucleus pulposus tissues was measured. Data are represented as the mean ± SD. Two-group comparisons were analyzed by Student’s t-test. Significant differences between the treatment and control groups are indicated as *P < 0.05, **P < 0.01, and ***P < 0.001, n = 3.

Fig 5: OATD-02 shows significant therapeutic efficacy in the human CML model using K562 cells. (A)—ARG1 and ARG2 expression was assessed in K562 cell lysates by SDS-PAGE/WB with specific antibodies; (B)—OATD-02 exhibited dose-dependent effect on the cell survival in a long-term K562 cell culture; (C)—Athymic nude mice were inoculated with K562 cells and test compound administration started when the xenografts became palpable (day 6); OATD-02 was dosed at 50 mg/kg (PO, BID) and Ref. ARGi was dosed at 100 mg/kg (PO, BID) until the end of the experiment; final tumour measurements were taken at day 19 post-inoculation and TGI was calculated (* 0.0172 < p < 0.0428, Kruskal–Wallis test with Dunn’s multiple comparisons test); (D)—T and NK cell-deficient mice (strain Fox Chase SCID Beige) were inoculated with K562 cells and OATD-02 was dosed at 50 mg/kg (PO, BID) from day 7 until the end of the experiment; final tumour volumes (day 19) were used for TGI calculations (* 0.0201 < p < 0.0449, U Mann–Whitney test).