RHOA mediated mechanical force generation through Dectin-1

Choraghe, Rohan P.; Kołodziej, Tomasz; Buser, Alan; Rajfur, Zenon; Neumann, Aaron K.

doi:10.1101/663526

Cited by 2 publications

(2 citation statements)

References 48 publications

(51 reference statements)

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“…RhoA is well known for its importance in many cell types by regulating the cytoskeleton remodeling through ROCK/MLCK pathway [ 30 , 50 ]. However, whether RhoA deletion alleviates the macrophage’s migration and phagocytosis through ROCK/MLCK pathway is unknown yet.…”

Section: Resultsmentioning

confidence: 99%

Macrophage-specific RhoA knockout delays Wallerian degeneration after peripheral nerve injury in mice

Wen

et al. 2021

J Neuroinflammation

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Background Plenty of macrophages are recruited to the injured nerve to play key roles in the immunoreaction and engulf the debris of degenerated axons and myelin during Wallerian degeneration, thus creating a conducive microenvironment for nerve regeneration. Recently, drugs targeting the RhoA pathway have been widely used to promote peripheral axonal regeneration. However, the role of RhoA in macrophage during Wallerian degeneration and nerve regeneration after peripheral nerve injury is still unknown. Herein, we come up with the hypothesis that RhoA might influence Wallerian degeneration and nerve regeneration by affecting the migration and phagocytosis of macrophages after peripheral nerve injury. Methods Immunohistochemistry, Western blotting, H&E staining, and electrophysiology were performed to access the Wallerian degeneration and axonal regeneration after sciatic nerve transection and crush injury in the LyzCre+/−; RhoAflox/flox (cKO) mice or Lyz2Cre+/− (Cre) mice, regardless of sex. Macrophages’ migration and phagocytosis were detected in the injured nerves and the cultured macrophages. Moreover, the expression and potential roles of ROCK and MLCK were also evaluated in the cultured macrophages. Results 1. RhoA was specifically knocked out in macrophages of the cKO mice; 2. The segmentation of axons and myelin, the axonal regeneration, and nerve conduction in the injured nerve were significantly impeded while the myoatrophy was more severe in the cKO mice compared with those in Cre mice; 3. RhoA knockout attenuated the migration and phagocytosis of macrophages in vivo and in vitro; 4. ROCK and MLCK were downregulated in the cKO macrophages while inhibition of ROCK and MLCK could weaken the migration and phagocytosis of macrophages. Conclusions Our findings suggest that RhoA depletion in macrophages exerts a detrimental effect on Wallerian degeneration and nerve regeneration, which is most likely due to the impaired migration and phagocytosis of macrophages resulted from disrupted RhoA/ROCK/MLCK pathway. Since previous research has proved RhoA inhibition in neurons was favoring for axonal regeneration, the present study reminds us of that the cellular specificity of RhoA-targeted drugs is needed to be considered in the future application for treating peripheral nerve injury.

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Section: Resultsmentioning

confidence: 99%

Macrophage-specific RhoA knockout delays Wallerian degeneration after peripheral nerve injury in mice

Wen

et al. 2021

J Neuroinflammation

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“…Many questions remain regarding the characteristics of this protrusion. One of them is if and how these force-developing protrusions are modified by forces that are produced by APCs such as dendritic cells (Choraghe et al, 2020;Heuzé et al, 2013;Ricart et al, 2011) but also what is the molecular machinery controlling the dynamic of these protrusions. In this report, we further dissect the dynamics of T cell protrusion by exploring the effect of well-defined forces exerted by the cell environment.…”

Section: Figure 1 (A) Micropipette Force Probe (Mfp)mentioning

confidence: 99%

Influence of external forces on actin‐dependent T cell protrusions during immune synapse formation

Zucchetti

Paillon

Markova

et al. 2021

Biology of the Cell

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Background Information We have previously observed that in response to antigenic activation, T cells produce actin‐rich protrusions that generate forces involved in T cell activation. These forces are influenced by the mechanical properties of antigen‐presenting cells (APCs). However, how external forces, which can be produced by APCs, influence the dynamic of the actin protrusion remains unknown. In this study, we quantitatively characterised the effects of external forces in the dynamic of the protrusion grown by activated T cells. Results Using a micropipette force probe, we applied controlled compressive or pulling forces on primary T lymphocytes activated by an antibody‐covered microbead, and measured the effects of these forces on the protrusion generated by T lymphocytes. We found that the application of compressive forces slightly decreased the length, the time at which the protrusion stops growing and retracts and the velocity of the protrusion formation, whereas pulling forces strongly increased these parameters. In both cases, the applied forces did not alter the time required for the T cells to start growing the protrusion (delay). Exploring the molecular events controlling the dynamic of the protrusion, we showed that inhibition of the Arp2/3 complex impaired the dynamic of the protrusion by reducing both its maximum length and its growth speed and increasing the delay to start growing. Finally, T cells developed similar protrusions in more physiological conditions, that is, when activated by an APC instead of an activating microbead. Conclusions Our results suggest that the formation of the force‐generating protrusion by T cells is set by an intracellular constant time and that its dynamic is sensitive to external forces. They also show that actin assembly mediated by actin‐related protein Arp2/3 complex is involved in the formation and dynamic of the protrusion. Significance Actin‐rich protrusions developed by T cells are sensory organelles that serve as actuators of immune surveillance. Our study shows that forces experienced by this organelle modify their dynamic suggesting that they might modify immune responses. Moreover, the quantitative aspects of our analysis should help to get insight into the molecular mechanisms involved in the formation of the protrusion.

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RHOA mediated mechanical force generation through Dectin-1

Cited by 2 publications

References 48 publications

Macrophage-specific RhoA knockout delays Wallerian degeneration after peripheral nerve injury in mice

Macrophage-specific RhoA knockout delays Wallerian degeneration after peripheral nerve injury in mice

Influence of external forces on actin‐dependent T cell protrusions during immune synapse formation

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