Internal and surface subpopulations of the major surface protease (MSP) of Leishmania chagasi

Yao, Chaoqun; Luo, Jiwen; Hsiao, Chia‐Hung Christine; Donelson, John E.; Wilson, Mary E.

doi:10.1016/j.molbiopara.2004.11.005

Cited by 22 publications

(44 citation statements)

References 45 publications

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“…A lag phase of 2 days was observed prior to the onset of logarithmic growth of stationary-phase promastigotes cultures (see Fig. S1 in the supplemental material), which is consistent with our previous data (13,14). Interestingly, the usual logarithmic phase of 3 to 5 days observed prior to the onset of logarithmic growth of metacyclic promastigote cultures was shortened by 1 full day in M␤CD-treated metacyclic promastigotes (Fig.…”

Section: Resultssupporting

confidence: 91%

Attenuation of Leishmania infantum chagasi Metacyclic Promastigotes by Sterol Depletion

et al. 2013

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The infectious metacyclic promastigotes of Leishmania protozoa establish infection in a mammalian host after they are deposited into the dermis by a sand fly vector. Several Leishmania virulence factors promote infection, including the glycosylphosphatidylinositol membrane-anchored major surface protease (MSP). Metacyclic Leishmania infantum chagasi promastigotes were treated with methyl-beta-cyclodextrin (M␤CD), a sterol-chelating reagent, causing a 3-fold reduction in total cellular sterols as well as enhancing MSP release without affecting parasite viability in vitro. M␤CD-treated promastigotes were more susceptible to complement-mediated lysis than untreated controls and reduced the parasite load 3-fold when inoculated into BALB/c mice. Paradoxically, M␤CD-treated promastigotes caused a higher initial in vitro infection rate in human or murine macrophages than untreated controls, although their intracellular multiplication was hindered upon infection establishment. There was a corresponding larger amount of covalently bound C3b than iC3b on the parasite surfaces of M␤CD-treated promastigotes exposed to healthy human serum in vitro, as well as loss of MSP, a protease that enhances C3b cleavage to iC3b. Mass spectrometry showed that M␤CD promotes the release of proteins into the extracellular medium, including both MSP and MSPlike protein (MLP), from virulent metacyclic promastigotes. These data support the hypothesis that plasma membrane sterols are important for the virulence of Leishmania protozoa at least in part through retention of membrane virulence proteins. Leishmania protozoa shuttle between a mammalian host as intracellular amastigotes and a sand fly vector as flagellated promastigotes. The sand fly acquires amastigote-laden cells during a blood meal. In the sand fly midgut, procyclic promastigotes derived from transformation of amastigotes undergo multiplication and development via intermediate stages, eventually yielding metacyclic promastigotes (1). The infectious metacyclic promastigote is inoculated into a pool of blood in the dermis of a mammalian host formed during a sand fly bite. Parasites are phagocytized by host macrophages, where they transform to amastigotes and multiply in parasitophorous vacuoles. Amastigotes spread to new macrophages at local or disseminated sites, perpetuating the infection and ultimately resulting in asymptomatic infections or symptomatic leishmaniasis (2). Various forms of leishmaniasis are endemic in 88 countries on four continents, leading to approximately two million new cases and 59,000 deaths annually (3).Both host and parasite factors contribute to the success of infection. On one hand, mammalian host environmental risk factors and genetic background influence the clinical manifestations of infection (4). On the other hand, parasite virulence determinants required for disease development include, but are not limited to, the major surface protease (MSP) (also called GP63 or leishmanolysin) and lipophosphoglycan (LPG) (5-8). These two molecules play both overl...

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Section: Resultssupporting

confidence: 91%

Attenuation of Leishmania infantum chagasi Metacyclic Promastigotes by Sterol Depletion

et al. 2013

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“…and other trypanosomatids (7,10,18,26,46). Moreover, a subpopulation of internal MSPs has been detected and appears to be stable for several days (42,47). Collectively, data generated from several laboratories, including our own, have demonstrated the existence of three subpopulations, i.e., surface-localized MSP, internal MSP, and released MSP.…”

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confidence: 77%

Internal and Surface-Localized Major Surface Proteases ofLeishmaniaspp. and Their Differential Release from Promastigotes

2007

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Major surface protease (MSP), also called GP63, is a virulence factor of Leishmania spp. protozoa. There are three pools of MSP, located either internally within the parasite, anchored to the surface membrane, or released into the extracellular environment. The regulation and biological functions of these MSP pools are unknown. We investigated here the trafficking and extrusion of surface versus internal MSPs. Virulent Leishmania chagasi undergo a growth-associated lengthening in the t 1/2 of surface-localized MSP, but this did not occur in the attenuated L5 strain. The release of surface-localized MSP was enhanced in a dose-dependent manner by M␤CD, which chelates membrane cholesterol-ergosterol. Furthermore, incubation of promastigotes at 37°C with Matrigel matrix, a soluble basement membrane extract of Engelbreth-Holm-Swarm tumor cells, stimulated the release of internal MSP but not of surface-located MSP. Taken together, these data indicate that MSP subpopulations in distinct cellular locations are released from the parasite under different environmental conditions. We hypothesize that the internal MSP with its lengthy t 1/2 does not serve as a pool for promastigote surface MSP in the sand fly vector but that it instead functions as an MSP pool ready for quick release upon inoculation of metacyclic promastigotes into mammals. We present a model in which these different MSP pools are released under distinct life cycle-specific conditions.The digenetic protozoa of Leishmania spp. shuttle between an extracellular promastigote form in the sand fly vector and an intracellular amastigote form in mammalian hosts, including humans. In the sand fly, the avirulent procyclic promastigotes develop to the virulent metacyclic organisms, a process termed metacyclogenesis that can be mimicked by in vitro cultivation of logarithmic-to stationary-phase promastigotes (36). Leishmania causes 1.5 to 2 million new cases of human leishmaniasis annually, with manifestations ranging from selfhealing cutaneous sores to life-threatening visceral leishmaniasis (8, 9). Among a few well-characterized Leishmania virulence factors is the major surface protease (MSP), also called GP63. MSP plays several important roles during Leishmania spp. infection of mammals, including (i) enhancing promastigote phagocytosis by macrophages, (ii) facilitating promastigote evasion of complement-mediated lysis, and (iii) promoting amastigote survival in the phagolysosomes of macrophages (see reference 45 for a review). There is also evidence suggesting that in the sand fly MSP plays a role in the early-stage development of promastigotes (16) and contributes to promastigote adhesion in the guts and salivary glands (see reference 37 for a review).MSP is encoded by a family of highly conserved genes organized in a tandem array. MSP genes (MSPs) and homologues have been found in all Leishmania spp. studied to date, as well as in other trypanosomatids, including the monoxenous insect parasite Crithidia and the extracellular mammalian parasite Trypanosoma brucei...

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“…We have not formally ruled out two less likely possibilities: (i) that some surface MSP isoforms are inaccessible to surface biotinylation due to the presence of densely packed LPG, a situation reminiscent of the failure of immunogold to label some MSPs on the cell surfaces of L. major promastigotes (86), and (ii) that MSPs are constantly internalized with biotin removal. The second explanation is also unlikely because of the following reasons: (i) one of the 11 major MSP isoforms detected on Western blots of total L. chagasi proteins separated by twodimensional SDS-PAGE is not surface biotinylated (110), (ii) intracellular MSP does not colocalize with the endosome marker FM4-64 by confocal microscopy and is instead found in a subregion of ER (111), and (iii) quantitation of MSPs by immunoelectron and fluorescence microscopy agrees with results of surface biotinylation (102,109). Together, these data suggest that a subpopulation of MSPs resides continuously at an internal location of promastigotes.…”

Section: "Abnormal" Msps Of Leishmanial Promastigotes: Functions Of Tmentioning

confidence: 92%

“…Several groups, including ours, have reported that some MSPs of several Leishmania spp. are intracellularly localized in promastigotes and/or are released into the culture medium (32,51,69,102,108,109) (Fig. 1).…”

Section: "Abnormal" Msps Of Leishmanial Promastigotes: Functions Of Tmentioning

confidence: 99%

“…These experiments revealed that one-fourth of the nascent MSPs remained internally for up to 6 days following biosynthesis, strongly supporting the existence of a stable internal subpopulation of MSPs. It appeared that only the mature 63-kDa form, not the 59-kDa protein, accounts for this subpopulation of internal MSPs (106,109). We have not formally ruled out two less likely possibilities: (i) that some surface MSP isoforms are inaccessible to surface biotinylation due to the presence of densely packed LPG, a situation reminiscent of the failure of immunogold to label some MSPs on the cell surfaces of L. major promastigotes (86), and (ii) that MSPs are constantly internalized with biotin removal.…”

Section: "Abnormal" Msps Of Leishmanial Promastigotes: Functions Of Tmentioning

confidence: 99%

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Major Surface Protease of Trypanosomatids: One Size Fits All?

Yao

2010

Infect Immun

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Trypanosomatids are a very diverse group of protozoa including many species of medical, veterinary, and/or economical importance. Leishmania spp. cause disease on the continents of Asia, Africa, Europe, and North and South America; Trypanosoma cruzi is the etiology of Chagas' disease in South and Central America; and Trypanosoma brucei infections result in African sleeping sickness. Four genera of heteroxenous trypanosomatids transmitted by insect vectors infect a wide range of hosts including humans, animals, and plants. Six genera of monoxenous trypanosomatids parasitize numerous species of insects. Due to this diversity, the life cycle of Leishmania spp. is presented as a model to which other heteroxenous and monoxenous groups will be briefly contrasted.During their life cycle, Leishmania spp. shuttle between a flagellated promastigote stage in the sand fly vector and a nonmotile amastigote stage in a mammalian host. During blood meals on infected hosts, the sand fly vectors ingest amastigote-laden macrophages (Mø). These amastigotes transform to procyclic promastigotes in the sand fly gut, multiply by binary fission, and eventually develop into metacyclic promastigotes, the infective stage for mammalian hosts including humans. The sand fly vectors, upon taking another blood meal, inoculate the metacyclic promastigotes into the dermis, where they are phagocytized by Mø of the mammalian hosts. Amastigotes, transformed from metacyclic promastigotes, multiply in parasitophorous vacuoles (PV) of the host's Mø. Multiplication of amastigotes eventually leads to rupture of the infected Mø and release of amastigotes, which infect additional Mø, perpetuating the cycle of replication (38).Other , Crithidia, Leptomonas, Herpetomonas, Rhynchoidomonas, and Phytomonas (87). Leishmania spp. harbor a zinc metalloprotease, discovered in the mid-1980s, on their surfaces (14,15,36,37,88). This enzyme, accounting for about 1% of the total protein in promastigotes of Leishmania major and Leishmania mexicana (2, 10) and being potentially important during different stages of the life cycle, soon became the object of much investigation (8,70,71,107). Although referred to here as major surface protease (MSP), this zinc metalloprotease has also been termed GP63, surface acid protease, promastigote surface protease, EC 3.4.24.36, and leishmanolysin.MSPs of Leishmania spp. belong to the M8 family of endopeptidases, sharing several characteristics with mammalian matrix metalloproteases. Similarities include degradation of the extracellular matrix, cell surface localization, protease activity requiring Zn 2ϩ , and inhibition of protease activity by * Mailing address:

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Internal and surface subpopulations of the major surface protease (MSP) of Leishmania chagasi

Cited by 22 publications

References 45 publications

Attenuation of Leishmania infantum chagasi Metacyclic Promastigotes by Sterol Depletion

Attenuation of Leishmania infantum chagasi Metacyclic Promastigotes by Sterol Depletion

Internal and Surface-Localized Major Surface Proteases ofLeishmaniaspp. and Their Differential Release from Promastigotes

Major Surface Protease of Trypanosomatids: One Size Fits All?

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