1. Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA 70433, USA.
2. Department of Neuroscience, Temple University Lewis Katz School of Medicine, Philadelphia, PA 19140, USA.
3. Key Laboratory of Cardiovascular and Cerebrovascular Medicine, Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, Jiangsu 211166, China.
4. Department of Immunology and Microbiology, Tulane University School of Medicine, New Orleans, LA 70112, USA.
5. Department of Hepatobiliary and pancreatic surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China.
6. Department of Clinical Laboratory Department, Shanghai Tenth People's Hospital of Tongji University, Shanghai 200072, China.
7. Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, Kansas 66160, USA; 8Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA.
8. Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA.
Rationale: Kupffer cells (KCs) play a crucial role in liver immune homeostasis through interacting with other immune cells and liver sinusoidal endothelial cells (LSECs). However, how KCs exactly interact with these cells for maintaining the homeostasis still require the further investigation. CXCL10 is a chemokine that has been implicated in chemoattraction of monocytes, T cells, NK cells, and dendritic cells, and promotion of T cell adhesion to endothelial cells. Although CXCL10 is also known to participate in the pathogenesis of hepatic inflammation, the degree to which it is functionally involved in the crosstalk between immune cells and regulation of immune response is still unclear.
Methods: To dynamically investigate the function of KCs, we used our recently developed rapid cell ablation model, intermedilysin (ILY)/human CD59 (hCD59)-mediated cell ablation tool, to selectively ablate KC pool under normal condition or concanavalin A (Con A)- induced hepatitis. At certain time points after KCs ablation, we performed flow cytometry to monitor the amount of hepatic infiltrating immune cells. mRNA array was used to detect the change of hepatic cytokines and chemokines levels. Cytokines and chemokines in the serum were further measured by LEGENDplexTM mouse proinflammatory chemokine panel and inflammation panel. Evans blue staining and transmission electron microscopy were used to investigate the interaction between KCs and LSECs in steady condition. CXCL10 neutralizing antibody and CXCL10 deficient mouse were used to study the role of CXCL10 in immune cell migration and pathogenesis of Con A-induced hepatitis.
Results: At steady state, elimination of KCs results in a reduction of hepatic infiltrating monocytes, T, B, and NK cells and a list of cytokines and chemokines at transcriptional level. In the meantime, the depletion of KCs resulted in increased sinusoidal vascular permeability. In the pathological condition, the KCs elimination rescues Con A-induced acute hepatitis through suppressing proinflammatory immune responses by down-regulation of hepatitis-associated cytokines/chemokines in serum such as CXCL10, and recruitment of infiltrating immune cells (monocytes, T, B, and NK cells). We further documented that deficiency or blockade of CXCL10 attenuated the development of Con A-induced hepatitis associated with reduction of the infiltrating monocytes, especially inflammatory Ly6Chi monocytes.
Conclusions: This study supports the notion that KCs actively interact with immune cells and LSECs for maintaining immune response and liver homeostasis. Our data indicate that the interplay between KCs and infiltrated monocytes via CXCL10 contribute to Con A-induced hepatitis.
Keywords: Hepatitis, Kupffer cells, CXCL10, Sinusoid endothelial cells, Cell ablation