macrophage depletion
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2022 ◽  
Vol 36 (2) ◽  
Author(s):  
Merlin Airik ◽  
Blake McCourt ◽  
Tugba Tastemel Ozturk ◽  
Amy B. Huynh ◽  
Xiaoyi Zhang ◽  
...  

2021 ◽  
Author(s):  
Aleksandar Murgaski ◽  
Mate Kiss ◽  
Helena Van Damme ◽  
Daliya Kancheva ◽  
Isaure Vanmeerbeek ◽  
...  

Agonistic αCD40 therapy has shown to inhibit cancer progression, but only in a fraction of patients. Hence, understanding the cancer cell-intrinsic and microenvironmental determinants of αCD40 therapy response is crucial to identify responsive patient populations and design efficient combination treatments. Here, we showed that the therapeutic efficacy of αCD40 in responder melanoma tumours, relied on pre-existing cDC1-primed CD8+ T cells, however cDC1s were dispensable after αCD40 administration. Surprisingly, in response to αCD40 the abundance of activated cDCs, potentially derived from cDC2s increased, thereby further activating antitumour CD8+ T cells. Hence, distinct cDC subsets are required to induce αCD40 responses. By contrast, lung tumours, characterised by a high abundance of macrophages, were resistant to αCD40 therapy. Combining αCD40 therapy with macrophage depletion led to tumour growth inhibition only in the presence of strong neoantigens. Accordingly, treatment with immunogenic cell-death inducing chemotherapy sensitised non-immunogenic tumours to αCD40 therapy.


2021 ◽  
Vol 2 (4) ◽  
pp. 101004
Author(s):  
Tivoli Nguyen ◽  
Jie Du ◽  
Yan Chun Li

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0260443
Author(s):  
Yushi Hayashi ◽  
Hidenori Suzuki ◽  
Wataru Nakajima ◽  
Ikuno Uehara ◽  
Atsuko Tanimura ◽  
...  

Although sensorineural hearing loss (SHL) is relatively common, its cause has not been identified in most cases. Previous studies have suggested that viral infection is a major cause of SHL, especially sudden SHL, but the system that protects against pathogens in the inner ear, which is isolated by the blood-labyrinthine barrier, remains poorly understood. We recently showed that, as audiosensory receptor cells, cochlear hair cells (HCs) are protected by surrounding accessory supporting cells (SCs) and greater epithelial ridge (GER or Kölliker’s organ) cells (GERCs) against viral infections. Here, we found that virus-infected SCs and GERCs induce HC death via production of the tumour necrosis factor-related apoptosis-inducing ligand (TRAIL). Notably, the HCs expressed the TRAIL death receptors (DR) DR4 and DR5, and virus-induced HC death was suppressed by TRAIL-neutralizing antibodies. TRAIL-induced HC death was not caused by apoptosis, and was inhibited by necroptosis inhibitors. Moreover, corticosteroids, the only effective drug for SHL, inhibited the virus-induced transformation of SCs and GERCs into macrophage-like cells and HC death, while macrophage depletion also inhibited virus-induced HC death. These results reveal a novel mechanism underlying virus-induced HC death in the cochlear sensory epithelium and suggest a possible target for preventing virus-induced SHL.


Author(s):  
Marian A. Ackun‐Farmmer ◽  
Baixue Xiao ◽  
Maureen R. Newman ◽  
Danielle S.W. Benoit

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Xinbei Tian ◽  
Ying Wang ◽  
Ying Lu ◽  
Weipeng Wang ◽  
Jun Du ◽  
...  

AbstractAlthough macrophages are recognized as important players in the pathogenesis of chronic liver diseases, their roles in cholestatic liver fibrosis remain incompletely understood. We previously reported that long noncoding RNA-H19 (lncRNA-H19) contributes to cholangiocyte proliferation and cholestatic liver fibrosis of biliary atresia (BA). We here show that monocyte/macrophage CD11B mRNA levels are increased significantly in livers of BA patients and positively correlated with the progression of liver inflammation and fibrosis. The macrophages increasingly infiltrate and accumulate in the fibrotic niche and peribiliary areas in livers of BA patients. Selective depletion of macrophages using the transgenic CD11b-diphtheria toxin receptor (CD11b-DTR) mice halts bile duct ligation (BDL)-induced progression of liver damage and fibrosis. Meanwhile, macrophage depletion significantly reduces the BDL-induced hepatic lncRNA-H19. Overexpression of H19 in livers using adeno-associated virus serotype 9 (AAV9) counteracts the effects of macrophage depletion on liver fibrosis and cholangiocyte proliferation. Additionally, both H19 knockout (H19−/−) and conditional deletion of H19 in macrophage (H19ΔCD11B) significantly depress the macrophage polarization and recruitment. lncRNA-H19 overexpressed in THP-1 macrophages enhance expression of Rho-GTPase CDC42 and RhoA. In conclusions, selectively depletion of macrophages suppresses cholestatic liver injuries and fibrosis via the lncRNA-H19 and represents a potential therapeutic strategy for rapid liver fibrosis in BA patients.


2021 ◽  
Vol 12 ◽  
Author(s):  
Micaela Orsi ◽  
Mihaly Palmai-Pallag ◽  
Yousof Yakoub ◽  
Saloua Ibouraadaten ◽  
Michèle De Beukelaer ◽  
...  

Macrophages are not only derived from circulating blood monocytes or embryonic precursors but also expand by proliferation. The origin determines macrophage fate and functions in steady state and pathological conditions. Macrophages predominantly infiltrate fibre-induced mesothelioma tumors and contribute to cancer development. Here, we revealed their ontogeny by comparing the response to needle-like mesotheliomagenic carbon nanotubes (CNT-7) with tangled-like non-mesotheliomagenic CNT-T. In a rat peritoneal cavity model of mesothelioma, both CNT induced a rapid macrophage disappearance reaction (MDR) of MHCIIlow resident macrophages generating an empty niche available for macrophage repopulation. Macrophage depletion after mesotheliomagenic CNT-7 was followed by a substantial inflammatory reaction, and macrophage replenishment completed after 7 days. Thirty days after non-mesotheliomagenic CNT-T, macrophage repopulation was still incomplete and accompanied by a limited inflammatory reaction. Cell depletion experiments, flow cytometry and RNA-seq analysis demonstrated that, after mesotheliomagenic CNT-7 exposure, resident macrophages were mainly replaced by an influx of monocytes, which differentiated locally into MHCIIhigh inflammatory macrophages. In contrast, the low inflammatory response induced by CNT-T was associated by the accumulation of self-renewing MHCIIlow macrophages that initially derive from monocytes. In conclusion, the mesotheliomagenic response to CNT specifically relies on macrophage niche recolonization by monocyte-derived inflammatory macrophages. In contrast, the apparent homeostasis after non-mesotheliomagenic CNT treatment involves a macrophage regeneration by proliferation. Macrophage depletion and repopulation are thus decisive events characterizing the carcinogenic activity of particles and fibres.


2021 ◽  
Vol 22 (Supplement_3) ◽  
Author(s):  
A Hess ◽  
LBN Langer ◽  
TL Ross ◽  
FM Bengel ◽  
JT Thackeray

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft (DFG) Introduction Balanced myocardial tissue inflammation following acute myocardial infarction (MI) is needed for optimal cardiac repair. Macrophages contribute to wound healing, but may also be deleterious. Purpose We investigated the impact of macrophage depletion on early cardiac inflammation and later functional outcome in two models of MI with variable transmurality. Methods C57BL/6N mice received clodronate-liposomes for macrophage depletion (n = 49) or control PBS-liposomes (n = 23). After 24h, mice underwent permanent occlusion (PO) or transient ischemia-reperfusion (I/R, 60min) of the left coronary artery or sham surgery. Cardiac inflammation was assessed on MI + 1d, 3d, and 7d by CXCR4-targeted PET/CT using 68Ga-pentixafor. 99mTc-sestamibi SPECT/CT and cardiac magnetic resonance (CMR) calculated infarct sizes and left ventricular (LV) function at 1wk and 6wks. 18F-NaF PET/CT measured tissue microcalcification at 4wks. Imaging signals were validated by ex vivo autoradiography and immunohistochemistry. Results Clodronate macrophage depletion did not affect infarct size compared to PBS, but perfusion defects at 6wks were significantly larger after PO compared to I/R (%LV, 32 ± 11 vs 14 ± 10, p = 0.01). In both models, infarct CXCR4 expression was higher after macrophage depletion vs PBS at all timepoints (%injected dose (ID)/g; d3: PO: 1.4 ± 0.2 vs 0.9 ± 0.1; I/R: 1.4 ± 0.2 vs 1.0 ± 0.02; p < 0.05), and confirmed by ex vivo autoradiography. Immunostaining demonstrated fewer macrophages and higher neutrophil content within the myocardium after macrophage depletion vs PBS at 1d, 3d, and 7d post-MI. Acute LV rupture after PO was more frequent in macrophage-depleted than PBS mice (37% vs 17%). Conversely, surviving PO mice showed a similarly impaired ejection fraction (EF) after macrophage depletion vs PBS at 6wks (%, 32 ± 9 vs 32 ± 11, p = 0.84). No acute LV rupture was observed after I/R, but macrophage depletion led to worse EF (%, 42 ± 11 vs 54 ± 3, p = 0.1). Macrophage-depleted mice exhibited a dense intracavity thrombus adherent to the infarct wall after either injury, as visualized on CMR at 1wk. 18F-NaF PET identified active calcification localized to the thrombus region 4wks after MI, which was colocalized to CT opaque regions at 6wks. Conclusion Macrophage depletion impairs cardiac repair via several mechanisms including neutrophil-dominated inflammation, LV thrombus formation and tissue calcification. This observation underscores the requirement of macrophages for effective healing and may explain adverse response to broad anti-inflammatory therapy in myocardial ischemia.


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