Fig 2: Time course of changes in the expression of IL-1R1 and the effects of administration of an IL-1 receptor antagonist (IL-1ra; 6, 20, or 60 ng) on the CCI-induced development of MA. (A,B) The graphs depicting the changes in the protein expression of IL-1R1 are shown in the upper portion, while representative immunoblots are presented in the lower portion. Results of Western blot analysis showed that the protein expression of IL-1R1 did not change in the ipsilateral (A) and contralateral (B) lumbar spinal cord dorsal horn following CCI. The spinal cord dorsal horn was sampled at 0, 1, 3, 7, and 14 days after surgery. n = 6 mice/group. (C,D) Paw withdrawal frequency (PWF, %) was measured in hind paws using a von-Frey filament (0.16 g). Sciatic nerve injury increased the PWF to mechanical stimuli in the ipsilateral hind paw from day 3 post-surgery, while administration of IL-1ra (20 or 60 ng) induced a significant increase in the PWF beginning on day 1 post-surgery (C). On the other hand, administration of IL-1ra had no effect on the PWF in the contralateral hind paw (D). n = 7 mice/group. *P < 0.05 vs. Sham; #P < 0.05 vs. vehicle-treated group. (E) Using a double immunohistochemical approach these representative images depict colocalization (yellow) of IL-1R1 (green) with GFAP (red, a marker of astrocytes), but not with NeuN (red, a marker of neurons) or Iba-1 (red, a marker of microglial cells) at day 1 post-surgery in the superficial dorsal horn of lumbar spinal cord in CCI mice. Scale bar = 40 µm.

Fig 3: Deletion of IL-1R1 preferentially inhibits Jak2V617F mutant hematopoietic stem/progenitor cells.a A scheme on competitive BM transplantation approach to assess the effects of IL-1R1 deletion on Jak2V617F mutant hematopoietic stem/progenitors is depicted. b Percentages of donor-derived (CD45.2+) total, myeloid cells (Gr1+), B cells (B220+), and T cells (TCRß+) in peripheral blood were measured every 4 weeks after pI-pC injection (n = 5, 4, 4, 4, 4, 4 recipient mice for Jak2VF/+ donor, n = 7, 7, 7, 6, 6, 6 mice for IL-1R1cKO; Jak2VF/+ donor at 0, 4, 8, 12, 16 and 20 weeks, respectively). Statistical significance was determined using multiple unpaired two-tailed t-tests. c Representative flow cytometric plots on the ratio of CD45.2+ vs. CD45.1+ LSK cells in the BM of recipient mice are shown on the left, and the percentages of donor-derived (CD45.2+) LSK in the BM of recipient mice (n = 5, 6) are shown in bar graphs as mean ± SEM on the right. d–f Percentages of donor-derived (CD45.2+) LK (d), Gr1+ (e) and CD41+ (f) cells in the BM of recipient animals at 20 weeks after pI-pC injection are shown as mean ± SEM (n = 4, 6). g–j Percentages of donor-derived (CD45.2+) LSK (n = 4, 5) (g), LK (n = 4, 5) (h), Gr1+ (n = 6, 6) (i) and CD41+ (n = 6, 6) (j) cells in the spleens of recipient animals are shown as mean ± SEM. k Spleen weights in the recipient animals of Jak2VF/+ and IL-1R1cKO; Jak2VF/+ mice BM (n = 4, 6). Statistical significances in c–k were determined using two-tailed unpaired t-test. Source data are provided as a Source Data file.

Fig 4: Treatment with anti-IL-1R1 antibody ameliorates BM fibrosis in homozygous Jak2V617F mouse model.a A scheme on the experimental design is depicted. b Peripheral blood WBC, neutrophil (NE), platelet (PLT) and red blood cell (RBC) counts were assessed at 3 and 6 weeks after the treatment (n = 7 mice per group). c, d Frequencies of Gr1+Mac1+ and CD41+ cells in the BM of Jak2VF/F mice treated with PBS and IL-1R1 Ab (n = 7 mice per group). e, f Frequencies of Gr1+Mac1+ and CD41+ cells in the spleens (SPL) of Jak2VF/VF mice treated with PBS and IL-1R1 Ab (n = 7 mice per group). g Frequencies of LSK, LT-HSC and ST-HSC in the BM of Jak2VF/VF mice treated with PBS and IL-1R1 Ab (n = 7 mice per group). Results are shown in bar graphs as mean ± SEM. h Frequencies of LK, CMP, GMP and MEP in the BM of Jak2VF/F mice treated with PBS and IL-1R1 Ab (n = 7 mice per group). i, j CFU-GM (i) and CFU-Mk (j) colonies in the BM of Jak2VF/VF mice treated with PBS and IL-1R1 Ab (n = 7 mice per group). k Spleen size/weight in Jak2VF/VF mice treated with vehicle (PBS) and IL-1R1 Ab are shown (n = 5 mice per group). l Representative images of the hematoxylin and eosin (H&E) and reticulin stained BM sections from Jak2VF/F mice treated with PBS or IL-1R1 Ab. Scale bars, 20 µm. Histological grade of BM fibrosis is shown in bar graphs as mean ± SEM (n = 5 mice per group). Statistical significances were determined using multiple unpaired two-tailed t-tests. Source data are provided as a Source Data file.

Fig 5: Exercise ameliorates anemia by its anti-inflammatory effects and the normalization of the metabolic profile.(A) IL-1ß levels were assessed in plasma of Ctrl, TB, and TB-ex 3.5 weeks after tumor initiation. (B) Blood lactate levels in rest and immediately after exhausting exercise. (C) Relative mRNA expression levels of Ldha and Ldhb that convert pyruvate to lactate or lactate to pyruvate, respectively, were measured in muscle. (D) To assess the expression of lactate transporters MCT1 and MCT4 and Il1r1, splenic phagocytes were FACS-sorted and mRNA levels were determined by qPCR. Expression of Il1b was also determined. (E) PKH26 fluorescently labeled healthy RBCs and healthy splenocytes were preincubated separately with pathophysiological levels of IL-1ß (1 pg/ml) or lactate (10 mM) and then coincubated with either untreated splenocytes or untreated RBCs. These conditions were compared to the Ctrl condition in which untreated splenocytes were coincubated with untreated RBCs. Quantification of the percentage PKH26high cells that engulfed complete RBCs is shown. Differences between groups (n = 5 to 7 per group) were tested with one-way ANOVAs followed by Tukey’s post hoc analysis, and data are represented as means + SEM. Data of in vitro erythrophagocytosis experiments consist of three independent experiments with three to four biological replicates, and Ctrl and treatment groups were compared by two-tailed unpaired t tests with Welch’s correction. If not indicated otherwise by a line, then asterisks indicate differences between Ctrl and treated group. *P < 0.05, **P < 0.01, and ***P < 0.001. Slc16a, solute carrier family 16 member.