scholarly journals A Bumpy Ride of Mycobacterial Phagosome Maturation: Roleplay of Coronin1 Through Cofilin1 and cAMP

2021 ◽  
Vol 12 ◽  
Author(s):  
Saradindu Saha ◽  
Arnab Hazra ◽  
Debika Ghatak ◽  
Ajay Vir Singh ◽  
Sadhana Roy ◽  
...  
Keyword(s):  
Immune Cells ◽  
Acid Stress ◽  
Camp Level ◽  
Innate Immune ◽  
Intracellular Camp ◽  
Innate Immune Cells ◽  
Phagosome Maturation ◽  
Sequence Of Events ◽  
Camp Levels ◽  
Phagocytic Uptake

Phagosome-lysosome fusion in innate immune cells like macrophages and neutrophils marshal an essential role in eliminating intracellular microorganisms. In microbe-challenged macrophages, phagosome-lysosome fusion occurs 4 to 6 h after the phagocytic uptake of the microbe. However, live pathogenic mycobacteria hinder the transfer of phagosomes to lysosomes, up to 20 h post-phagocytic uptake. This period is required to evade pro-inflammatory response and upregulate the acid-stress tolerant proteins. The exact sequence of events through which mycobacteria retards phagolysosome formation remains an enigma. The macrophage coat protein Coronin1(Cor1) is recruited and retained by mycobacteria on the phagosome membrane to retard its maturation by hindering the access of phagosome maturation factors. Mycobacteria-infected macrophages exhibit an increased cAMP level, and based on receptor stimulus, Cor1 expressing cells show a higher level of cAMP than non-Cor1 expressing cells. Here we have shown that infection of bone marrow-derived macrophages with H37Rv causes a Cor1 dependent rise of intracellular cAMP levels at the vicinity of the phagosomes. This increased cAMP fuels cytoskeletal protein Cofilin1 to depolymerize F-actin around the mycobacteria-containing phagosome. Owing to reduced F-actin levels, the movement of the phagosome toward the lysosomes is hindered, thus contributing to the retarded phagosome maturation process. Additionally, Cor1 mediated upregulation of Cofilin1 also contributes to the prevention of phagosomal acidification, which further aids in the retardation of phagosome maturation. Overall, our study provides first-hand information on Cor1 mediated retardation of phagosome maturation, which can be utilized in developing novel peptidomimetics as part of host-directed therapeutics against tuberculosis.

scholarly journals TNF and CD28 Signaling Play Unique but Complementary Roles in the Systemic Recruitment of Innate Immune Cells afterStaphylococcus aureusEnterotoxin A Inhalation

2016 ◽  
Vol 196 (11) ◽  
pp. 4510-4521 ◽  
Author(s):  
Julia Svedova ◽  
Naomi Tsurutani ◽  
Wenhai Liu ◽  
Kamal M. Khanna ◽  
Anthony T. Vella
Keyword(s):  
Immune Cells ◽  
Innate Immune ◽  
Innate Immune Cells

scholarly journals POS0369 ELEVATED EXPRESSION OF TIM-3 ON NEUTROPHILS CORRELATES WITH DISEASE ACTIVITY AND SEVERITY OF ANKYLOSING SPONDYLITIS

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 414.2-415
Author(s):  
X. Huang ◽  
T. W. Li ◽  
J. Chen ◽  
Z. Huang ◽  
S. Chen ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Ankylosing Spondylitis ◽  
Disease Activity ◽  
Immune Cells ◽  
Clinical Manifestations ◽  
Innate Immune ◽  
Innate Immune Cells ◽  
Bacterial Killing ◽  
Markers Of Inflammation ◽  
Significant Difference

Background:Ankylosing spondylitis (AS) is a type of common, chronic inflammatory disease that compromises the axial skeleton and sacroiliac joints, causing inflammatory low back pain and progressive spinal stiffness, over time some patients develop spinal immobility and ankylosis which can lead to a decrease in quality of life. The last few decades, evidence has clearly indicated that neutrophil also plays key roles in the progression of AS. However, the immunomodulatory roles and mechanisms of neutrophils in AS are poorly understood. T-cell immunoglobulin and mucin domain-containing protein 3 (Tim-3) has been reported as an important regulatory molecule, expressed and regulated on different innate immune cells, plays a pivotal role in several autoimmunity diseases. Recent study indicates that Tim3 is also expressed on neutrophils. However, the frequency and roles of Tim3-expressing neutrophils in AS was not clear.Objectives:In this study, we investigated the expression of Tim3 on neutrophils in AS patients and explored the correlation between the level of Tim3-expressing neutrophils and the disease activity and severity of AS.Methods:Patients with AS were recruited from Guangdong Second Provincial General Hospital (n=62). Age/sex-matched volunteers as Healthy controls (HC) (n=39). The medical history, clinical manifestations, physical examination, laboratory measurements were recorded. The expression of costimulatory molecules including programmed death 1 (PD-1), Tim-3 on neutrophils were determined by flow cytometry. The mRNA expression of PD-1 and Tim-3 was determined by real-time PCR. The levels of Tim3-expressing neutrophils in AS patients were further analyzed for their correlation with the markers of inflammation such as ESR,CRP,WBC and neutrophil count(NE), as well as disease activity and severity of AS. The expression of Tim3 on neutrophils was monitored during the course of treatment (4 weeks).Results:The expression of Tim3 on neutrophils in patients with AS was increased compared to the HC (Figure 1A). However, significant difference was observed in the frequency of PD-1-expressing neutrophils between AS patients and HC (Figure 1B). The expression analysis of Tim-3 mRNA, but not PD-1, confirmed the results obtained from flow cytometry (Figure 1C). The level of Tim3-expressing neutrophils in patients with AS showed an positive correlation with ESR, CRP and ASAS-endorsed disease activity score (ASDAS) (Figure 1D). Moreover, the frequency of Tim3-expressing neutrophils in active patients(ASDAS≥1.3) was increased as compare with the inactive patients (ASDAS<1.3) (Figure 1E). As shown in Figure 1F, the frequency of Tim3-expressing neutrophils decreased after the treatment.Conclusion:Increased Tim-3 expression on neutrophils may be a novel indicator to assess disease activity and severity in AS, which may serves as a negative feedback mechanism preventing potential tissue damage caused by excessive inflammatory responses in AS patients.References:[1]Han, G., Chen, G., Shen, B. & Li, Y., Tim-3: an activation marker and activation limiter of innate immune cells. FRONT IMMUNOL 4 449 (2013).[2]Vega-Carrascal, I. et al., Galectin-9 signaling through TIM-3 is involved in neutrophil-mediated Gram-negative bacterial killing: an effect abrogated within the cystic fibrosis lung. J IMMUNOL 192 2418 (2014).Figure 1.(A,B)The expression of Tim3 and PD-1 on neutrophils in AS and HC were determined by flow cytometry.(C) The expression of Tim3 and PD-1 on neutrophils in AS and HC were determined by RT-PCR.(D)The correction between Tim3-expressing neutrophils and ESR,CRP,ASDAS.(E) The expression of Tim3 on neutrophils in active and inactive patients.(F) Influence of treatment on the frequency of Tim3-expressing neutrophils.Disclosure of Interests:None declared

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