Fig 1: Phenotypic features in Jak1 H595D/+;I596I/+;Y597Y/+ mice. (A, B) The gross appearance of WT (A) and Jak1 H595D/+;I596I/+;Y597Y/+ (B) at 4 weeks of age. The Jak1 H595D/+;I596I/+;Y597Y/+ mouse shows scaling on the ears, the extremities, and the tail. (C, D) Hematoxylin and eosin staining of the skin reveals acanthosis, hyperkeratosis and parakeratosis in the Jak1 H595D/+;I596I/+;Y597Y/+ mouse (D), but not in the WT mouse (C). Scale bars = 50 µm. (n = 3) (E, F) Histology of liver sections from the Jak1 H595D/+;I596I/+;Y597Y/+ mice (F) and the WT mice (E) stained with hematoxylin and eosin. Scale bars = 50 μm. (n = 3) (G) Sequence data of Jak1 around the mutations in the Jak1 H595D/+;I596I/+;Y597Y/+, Jak1 I596I/+;Y597Y/+ and Jak1 +/- mice. The black line indicates c.1783C>G (H595D). The dotted lines indicate two synonymous changes: c.1788C>A (I596I) and c.1791T>C (Y597Y). (H) A graph of the overall survival rate (Jak1 H595D/+;I596I/+;Y597Y/+: n = 7, WT: n = 10, Jak1 I596I/+;Y597Y/+: n=10). Log-rank test, WT vs Jak1 H595D/+;I596I/+;Y597Y/+ mice: p value < 0.0001, Jak1 I596I/+;Y597Y/+ vs Jak1 H595D/+;I596I/+;Y597Y/+ mice: p value < 0.0001. (I) Immunohistochemical analysis by using the anti-p-JAK1 antibody for the palmar skin of the Jak1 H595D/+;I596I/+;Y597Y/+ mice and the WT mice. Scale bars = 50 µm. (n = 3).
Fig 2: Global gene expression profiling of the RNA samples in Jak1 H595D/+;I596I/+;Y597Y/+ mice. Gene set enrichment analysis using the hallmark gene set database. (A, B) Skin. Genes associated with HALLMARK_INTERFERON_GAMMA_RESPONSE (A) and HALLMARK_TNFA_SIGNALING_VIA_NFKB (B) are relatively upregulated in skin samples from the Jak1 H595D/+;I596I/+;Y597Y/+ mice. (C, D) Brain. Genes associated with STARK_PREFRONTAL_CORTEX_22Q11_DELETION_DN are downregulated in brain samples from the Jak1 H595D/+;I596I/+;Y597Y/+ mice. The red dots in (D) indicate genes in this gene set. Blue dots: the other genes. (E, F) Liver. Genes associated with HALLMARK_INTERFERON_GAMMA_RESPONSE are upregulated in liver samples from the Jak1 H595D/+;I596I/+;Y597Y/+ mice. The red dots in (F) indicate genes in this gene set. Blue dots: the other genes. NES, normalized enrichment score; FDR, false discovery rate.
Fig 3: Clinicopathologic features of the present patient with a JAK1 mutation. (A) Family tree of the present pedigree. (B, C) Scratched erythema and small red papules are seen on the trunk (B) and the back (C). (D) A biopsy sample from erythematous skin of the proband shows compact hyperkeratosis, moderate acanthosis, mild spongiosis and lymphocytic infiltration within the epidermis and the upper dermis. Scale bar = 100 µm. (E) Histologically, the structure of the liver parenchyma has been remodelled into a nodule by fibrosis, resulting in cirrhosis. Scale bar = 500 µm. (F) Inflammatory cell infiltration mainly composed of small lymphocytes (a few plasma cells) is observed in the nodule, accompanied by a mild necrotic inflammatory reaction with hepatocyte shedding. Scale bar = 50 µm. (G) Sanger sequencing reveals the heterozygous missense mutation c.1786C>G (H596D) in JAK1. (H) JAK1 amino-acid sequence alignment shows the level of conservation in diverse species of the amino-acid p.H596 (red box), which was altered by the missense mutation in the present patient. (I) The epidermis in an affected lesion from the patient and normal skin from a healthy donor were stained with anti-p-JAK1 antibody. Scale bars = 50 µm. MutationTaster (http://www.mutationtaster.org/).
Fig 4: A schematic of the JAK1 domain structure, and inflammatory pathways associated with JAK1 hyperactivation. (A) A schematic of the functional domains and the site of the reported gain-of-function germline mutations in humans (upper) and in mice (lower). The mutations in the present human case and in Jak1 H595D/+;I596I/+;Y597Y/+ mice are marked by pink arrows. Sites of the previously reported mutations are indicated by grey arrows. FERM, FERM (F for 4.1 protein, E for ezrin, R for radixin and M for moesin) domain; SH2, Src homology 2 domain; STYKc, the serine-threonine/tyrosine-protein kinase, catalytic domain (also called the pseudokinase domain); TyrKc, the tyrosine kinase catalytic domain. (B) Theory on the pathogenesis of the inflammatory pathways associated with JAK1 hyperactivation.
Fig 5: Expression of JAK1, p-JAK1, STAT3 and p-STAT3 protein in skin tissue (β-actin image for control were the same in Figure 5 and Figure 6). (A) Normal control group; (B) Model group. (C) OMT-H group. (D) OMT-M group. (E) OMT-L group. (F) Statistical data of expression of JAK1, p-JAK1, STAT3 and p-STAT3 protein in each group. (##, p < .01, vs. Control group; **, p < .01, vs. model group).
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