Three‐dimensional invasion of macrophages is mediated by cysteine cathepsins in protrusive podosomes

Abstract

IntroductionThe ability of macrophages (Mfs) to progress to specific tissues, increase matrix remodeling, and induce angiogenesis is essential for their normal physiological function [1,2]. In addition, tissue infiltration of Mfs is also involved in pathological processes such as chronic inflammation, atherosclerosis, neurodegenerative disorders, and cancer progression [3]. The presence of Mfs Correspondence: Dr. Bojana Mirković e-mail: bojana.mirkovic@ffa.uni-lj.si within tumors is generally a marker of poor prognosis since they enhance angiogenesis and metastasis [4]. Furthermore, tumorassociated Mfs are emerging as essential matrix-remodeling cells during tumor-cell invasion. They have been reported to be present at high frequency at the invasive front of the tumor, where the breakdown of extracellular matrix (ECM) occurs [5]. Therefore, there is a great need to specifically control tissue infiltration of Mfs by targeting Mf migration-related molecules [6]. * These authors contributed equally to the present work. Eur. J. Immunol. 2012. 42: 3429-3441 Mf migration has been studied extensively in two dimensions (2D) on artificial substrates; however, in vivo Mfs migrate through physiological and pathological tissue and interact with the surrounding three-dimensional (3D) ECM, including basement membrane, collagen-rich interstitial matrices, and dense tissues such as tumors. Cells of different origins and/or at different differentiation stages use distinct mechanisms of cell motility in the 3D environment. In the mesenchymal mode, cells wider than the matrix pore size degrade the matrix via proteolytic and force-based matrix remodeling, thus migrating in a "path-generating" manner, while amoeboid cells squeeze through pre-existing pores in a proteaseindependent fashion in a "path-finding" mode [7,8]. The first 3D migration studies performed on cells of the immune system suggested that these cells migrate in a protease-independent fashion [7,9]. In contrast, a recent study demonstrated that Mfs adapt their migration strategy depending on the architecture of the 3D environment. In this study, Mfs were found to use the amoeboid migration mode in fibrillar collagen I and the mesenchymal migration mode in dense substrates, such as Matrigel and gelled collagen I [10].The invasion of cancer cells is facilitated by ECM-degrading invadopodia [11]. Podosomes are structures functionally similar to the invadopodia that are found in Mfs, osteoclasts, and DCs [12,13]. During migration on 2D surfaces [14], dot or ringlike podosomes form at the ventral surface of the migrating cells where they establish direct contact with the substratum and are also involved in matrix degradation [11]. Structurally, podosomes comprise a concentrated core of F-actin and actin-regulatory proteins [14]. Surrounding the core is a ring region that contains scaffolding-, signaling-, and integrin-binding proteins, including the typical focal adhesion proteins vinculin, talin, paxillin, and FAK [15]. When Mfs migrate in a 3D environment (i.e., migra...

Tuberculosis is associated with expansion of a motile, permissive and immunomodulatory CD16+ monocyte population via the IL-10/STAT3 axis

“…To begin, we provided evidence that these cells display an enhanced capacity to migrate through dense matrices in an MMP-dependent manner contrasting with our previous observations that 3D migration in dense matrices rather involves cathepsins [45,47,58,59]. While we cannot exclude that chemokines present in cmMTB could be involved in the migration capacity of CD16 + C-D163 + MerTK + pSTAT3 + monocyte-macrophages, we showed that STAT3-dependent acquisition of the M2-like phenotype is essential for the enhanced motility and extracellular matrix remodeling activity in these cells.…”

Podosomes in space

“…2). 17,[57][58][59] In good agreement with podosomes as local sites of matrix degradation, Figure 2. Macrophage podosomes in 2D and 3D.…”

“…Still, force generation by migrating primary human macrophages on 3D fibrillar collagen has been observed (C. Wiesner et al, unpublished data). 62 To date, degradation of extracellular matrix is the best studied function of 3D podosomes, 17,57,59,62 as described in the following sections. Collectively, these results indicate that 3D podosomes observed in collagen and Matrigel TM networks indeed constitute the 3D counterparts of the classical podosomes found in 2D.…”

“…47,49 Comparable to their 2D counterparts, 3D podosomes formed within collagen gels have been shown to be targeted by proteases and to represent sites of focal degradation in 3D environments. 57,59,62 In addition to focalized matrix degradation, 3D podosomes probably also participate in the formation of tunnels in the matrix, as observed when macrophages migrate into 3D Matrigel TM . 57 To date, several types of proteases involved in the breakdown of ECM components have been identified, 65 including metalloproteases such as matrix metalloproteases (MMPs) and ADAMs (a disintegrin and metalloprotease), 67 as well as serine proteases and their associated receptors, the plasmin activation (PA) system, 68,69 and cysteine proteases (e.g., cysteine cathepsins [Cts]).…”

Rho/ROCK pathway inhibition by CDK inhibitor p27kip1 participates in the onset of macrophage 3D-mesenchymal migration

“…In contrast, macrophage mesenchymal migration is inhibited by protease inhibitors but not by ROCK inhibitors (Van Goethem et al, 2010). In contrast to tumour cell mesenchymal migration, which mainly depends on matrix metalloprotease (MMP) activity, macrophage mesenchymal migration can be mediated by other protease families, including lysosomal cysteine cathepsins (Jevnikar et al, 2012;Van Goethem et al, 2010), in addition to MMPs such as MT1-MMP Wiesner et al, 2013). Macrophage mesenchymal migration, but not amoeboid migration, is also dependent on Hck (Cougoule et al, 2010), Filamin-A (Guiet et al, 2012) and 3D-podosomes .…”