Prof. Dr. Friedrich Frischknecht

freddy.frischknecht@med.uni-heidelberg.de

Phone: ++49-(0)6221–56-6537

From Plasmodium sporozoite biology to interventions against malaria

Projects

We study malar­ia par­a­sites because they are both impor­tant human pathogens and diver­gent eukary­ot­ic cells fea­tur­ing a unique biol­o­gy. Our lab is main­ly inter­est­ed in under­stand­ing the role of diverse pro­teins in the motil­i­ty of malar­ia par­a­site, pri­mar­i­ly Plas­mod­i­um sporo­zoites the forms trans­mit­ted by the mos­qui­to. How­ev­er, we also study oth­er forms that rely on micro­tubules or actin to move with­in and across dif­fer­ent tis­sues. We also inves­ti­gate new ways to diag­nose and poten­tial­ly con­trol malar­ia.

1 | Identification of new Plasmodium biology in the mosquito

To infect the mos­qui­to and be effi­cient­ly trans­mit­ted, the malar­ia par­a­site needs to move. In order to under­stand how par­a­sites move we first need to know which pro­teins are essen­tial for motil­i­ty. To iden­ti­fy new can­di­date pro­teins that are secret­ed by the par­a­sites at dif­fer­ent live cycle stages (game­to­cytes, ookinetes, sporo­zoites) we use pro­teom­ic approach­es. This has iden­ti­fied a large num­ber of nov­el pro­teins that we are now char­ac­ter­iz­ing by the gen­er­a­tion of gene dele­tion mutants and par­a­site lines express­ing flu­o­res­cent­ly tagged pro­teins. We also express some of them in vit­ro for bio­chem­i­cal and struc­tur­al analy­sis.

Fig­ure 1| Plas­mod­i­um sporo­zoite as seen by scan­ning elec­tron microscopy (false col­or added). Pho­to by Lean­dro Lem­gru­ber.

2 | Understanding the divergent function of conserved proteins

Sev­er­al pro­teins are known key play­ers in sporo­zoite motil­i­ty, includ­ing trans-mem­brane adhe­sion pro­teins at the plas­ma mem­brane and pro­teins of the actin cytoskele­ton. The adhe­sion pro­teins con­tain con­served domains found across most eukary­otes. How­ev­er there are inter­est­ing dif­fer­ences in their lig­and speci­fici­ty, which we aim to under­stand by gen­er­at­ing par­a­site lines express­ing adhe­sion pro­teins that con­tain domains from dif­fer­ent organ­isms. Also actin and actin bind­ing pro­teins are very impor­tant for sporo­zoite motil­i­ty. Again, the actin looks very sim­i­lar to actin from yeast or humans, how­ev­er, in Plas­mod­i­um it only makes short and high­ly dynam­ic fil­a­ments. We aim to iden­ti­fy which amino acids in actin are caus­ing these fun­da­men­tal­ly dif­fer­ent char­ac­ter­is­tics. Also some very con­served actin bind­ing pro­teins con­tain domains not known from oth­er organ­isms or func­tion in anal­o­gous, yet dif­fer­ent ways and we address these by a mix of genet­ic, bio­chem­i­cal and cell biol­o­gy approach­es.

Fig­ure 2 | Expres­sion of actin from rab­bit mus­cle or Plas­mod­i­um or chimeric pro­teins in mam­malian cells shows their dis­tinct local­iza­tion prop­er­ties. The sin­gle point mutant N41H can allow Plas­mod­i­um actin to local­ize like rab­bit actin. From Dou­glas et al., Plos Biol., 2018.

 

 

 

3 | Generation of new types of attenuated parasites for experimental vaccinations

Par­a­site lines that arrest their growth in the liv­er have been used for exper­i­men­tal vac­ci­na­tions as well as in sev­er­al clin­i­cal tri­als. Through genet­ic mod­i­fi­ca­tion such par­a­site lines can be gen­er­at­ed yet some­times the arrest is not 100% lead­ing to infec­tions and dis­ease while some­times the effi­ca­cy of the atten­u­at­ed par­a­site to pro­tect from dis­ease is low. We work on new types of atten­u­at­ed par­a­sites that arrest their growth either in the liv­er or the blood stage and test them in mice with the ulti­mate goal of trans­lat­ing the results into clin­i­cal tri­als.

Fig­ure 4 | Liv­er cell infect­ed with a Plas­mod­i­um par­a­site. Cyan shows the live cell nuclei as well as the small nuclei of the par­a­site. In red the par­a­site cyto­plasm and in yel­low the host cell actin cytoskele­ton are visu­al­ized. Pho­to by Mirko Singer.

4 | Development of new diagnostic tools

We recent­ly start­ed to col­lab­o­rate with two com­pa­nies, Intu­ity and Zen­dia to devel­op new ways of diag­nos­ing malar­ia. While Intu­ity build a cheep micro­scope and an algo­rithm based on arti­fi­cial intel­li­gence to spot and count the par­a­sites in a blood smear, Zen­dia aims at devel­op­ing a rapid diag­nos­tic test based on the flu­o­res­cent detec­tion of par­a­sites.

Selected Publications

Com­plete pub­li­ca­tion list (PubMed)

Frischknecht, F., More­au, V., Röttger, S., Gon­floni, S., Reck­mann, I., Super­ti-Fur­ga, G. and Way, M. (1999) Actin-based motil­i­ty of vac­cinia virus mim­ics recep­tor tyro­sine kinase sig­nalling, Nature, 401:926–929.

Amino, R., Thiberge, S., Mar­tin, B., Cel­li, S., Shorte, S. L., Frischknecht, F. and Ménard R. (2006) Quan­ti­ta­tive imag­ing of malar­ia par­a­site trans­mis­sion to the mam­malian host, Nat. Med. 12:220–224.

Cyrk­laff, M., Kudrya­shev, M., Leis, A., Leonard, K., Baumeis­ter, W., Ménard, R., Meiss­ner, M., and Frischknecht, F. (2007) Cry­o­elec­tron tomog­ra­phy reveals peri­od­ic lumi­nal mate­r­i­al in sub­pel­lic­u­lar micro­tubules from api­com­plex­an par­a­sites, J. Exp. Med. 204:1281–1287.

Mün­ter, S., Sabass, B., Sel­hu­ber-Unkel, C., Kudrya­shev, M., Hegge, S., Spatz, J. P., Engel, U., Matuschews­ki, K., Schwarz, U. S. and Frischknecht, F. (2009) Plas­mod­i­um sporo­zoite motil­i­ty is mod­u­lat­ed by the turnover of dis­crete adhe­sion sites, Cell Host Microbe 6:551–562.

Hegge, S., Mün­ter, S., Stein­büchel, M., Heiss, K., Engel, U., Matuschews­ki, K. and Frischknecht, F. (2010), Mul­ti­step adhe­sion of Plas­mod­i­um sporo­zoites, FASEB J. 24:2222–2234.

Hell­mann, J. K., Mün­ter, S., Kudrya­shev, M., Schulz, S., Heiss, K., Müller, A.-K. Matuschews­ki, K., Spatz, J. P., Schwarz, U. S. and Frischknecht, F. (2011) Envi­ron­men­tal con­straints guide migra­tion of malar­ia par­a­sites dur­ing trans­mis­sion, PLoS Pathog, 7:e1002080.

Kudrya­shev, M., Mün­ter, S., Lem­gru­ber, L., Mon­tagna, G., Matuschews­ki, K., Stahlberg, H., Meiss­ner, M., Cyrk­laff, M. and Frischknecht, F. (2012) Struc­tur­al basis for chi­ral­i­ty and direct­ed Plas­mod­i­um sporo­zoite migra­tion, Cell. Micro­bi­ol. 14:1757–1768.

Singer, M., Mar­shall, J., Heiss, K., Mair, G. R., Grimm, D., Mueller A. K. and Frischknecht, F. (2015) Zinc-fin­ger nucle­ase-based dou­ble strand breaks atten­u­ate malar­ia par­a­sites and reveal rare micro-homol­o­gy medi­at­ed end join­ing, Genome Biol. 16:249.

Quadt, K. A., Stre­ich­fuss, M., More­au, C. A. Spatz, J. P. and Frischknecht, F. (2016) Cou­pling of ret­ro­grade flow to force pro­duc­tion dur­ing malar­ia par­a­site migra­tion, ACS Nano 10:2091–2102.

Kumar, H., Sat­tler, J. M., Singer M., Heiss, K., Reinig, M., Ham­mer­schmidt-Kam­per, C., Heus­sler, V. T., Mueller, A.K. and Frischknecht F. (2016) Pro­tec­tive effi­ca­cy and safe­ty of liv­er stage atten­u­at­ed malar­ia par­a­sites, Sci. Rep. 6:26824.

Kehrer, J., Frischknecht, F. and Mair G. R. (2016) Pro­teom­ic analy­sis of the Plas­mod­i­um berghei game­to­cyte egres­some and vesic­u­lar bioID of osmio­philic body pro­teins iden­ti­fied MTRAP as an essen­tial fac­tor for par­a­site trans­mis­sion, Mol.  Cell. Pro­teom. 15:2852–2862.

Bane, K., Lep­per, S., Kehrer, J., Sat­tler, J. M., Singer, M., Reinig, M., Heiss, K., Baum, J., Mueller, A. K. and Frischknecht, F. (2016) The actin fil­a­ment-bind­ing pro­tein coro­nin reg­u­lates motil­i­ty in Plas­mod­i­um sporo­zoites, PLoS Pathog. 12:e1005710.

More­au, C., Bhar­gav, S. P., Kumar, H. Quadt, K., Piirainen, H., Strauss, L., Kehrer, J., Stre­ich­fuss, M., Spatz, J. P., Wade, R. C., Kur­su­la, I. and Frischknecht, F. (2017) A unique pro­fil­in-actin inter­face is impor­tant for malar­ia par­a­site motil­i­ty, PLoS Pathog. 13:e1006412.

Klug, D. and Frischknecht, F. (2017) Motil­i­ty pre­cedes egress of malar­ia par­a­sites from oocysts, eLife, e19157.

Dou­glas, R., Nan­dekar, P., Akto­ries, J.-E., Kumar, H., Weber, R., Singer, M., Lep­per, S., Sadiq, S. K., Wade, R. C. and Frischknecht, F. (2018) Inter-sub­unit inter­ac­tions dri­ve diver­gent dynam­ics in mam­malian and Plas­mod­i­um actin fil­a­ments, PLoS Biol. 16:e2005345.

Spreng, B., Fleck­en­stein, H., Kübler, P., Di Bia­gio, C., Benz, M., Patra, P., Schwarz, U. S., Cyrk­laff, M. and Frischknecht, F. (2019) Micro­tubule num­ber and length deter­mine cel­lu­lar shape and func­tion in Plas­mod­i­um, EMBO J. in press.

Review arti­cles:

Frischknecht, F. and Fack­ler, O. T. (2016) Exper­i­men­tal sys­tems for study­ing Plas­mod­i­um-HIV coin­fec­tions, FEBS Lett. 590:2000–2013. (review)

Frischknecht, F. and Matuschews­ki, K. (2017) Plas­mod­i­um sporo­zoite biol­o­gy, in D. Wirth and P. Alon­so (eds), Malar­ia: Biol­o­gy in the Era of Erad­i­ca­tion, Cold Spring Harb. Per­spect. Med. 7:a025478. (review)

Singer, M. and Frischknecht, F. (2017) Time for genome edit­ing: next-gen­er­a­tion atten­u­at­ed malar­ia par­a­sites, Trends Par­a­sitol. 33, 202–213, 2017. (review)

Cyrk­laff, M., Frischknecht, F. and Kudrya­shev, M. (2017)  Func­tion­al insights into pathogen biol­o­gy from 3D elec­tron microscopy, FEMS Micro­bi­ol. Rev. 41:828–853. (review)