Research Projects: Musculoskeletal Systems Biology Lab

Neu­ro­mus­cu­lar Reg­u­la­tion of Bone in the Zebrafish Skeleton

zebrafish

Large-scale bio­log­i­cal approaches such as for­ward screens and sys­tems biology-based inves­ti­ga­tions are rec­og­nized to be vital for the advance­ment of bio­med­ical research. Zebrafish (a small trop­i­cal fresh­wa­ter fish that has gained promi­nence for its use in devel­op­men­tal biol­ogy) are ideal for such approaches due to their unique attrib­utes such as opti­cal trans­parency, ease of genetic manip­u­la­tion, small size, and low cost. We are cur­rently devel­op­ing new bone phe­no­typ­ing tech­nolo­gies and mod­els of neuromuscular-mediated bone patholo­gies in zebrafish to enable systems-based inves­ti­ga­tions of nerve, mus­cle, and bone inter­ac­tions. An exam­ple can be seen in the above schematic, which demon­strates the gen­er­a­tion of a mus­cu­loskele­tal “bar­code” con­tain­ing 576 dif­fer­ent descrip­tors of axial mus­cle and bone mor­phol­ogy for a sin­gle zebrafish. The bar­code was com­puted using a rapid MicroCT-based phe­no­typ­ing plat­form which we devel­oped. Such bar­codes can be used to iden­tify emer­gent or coor­di­nated behav­iors between many dif­fer­ent mus­cles and bones in nor­mal and patho­log­i­cal conditions.

Bone Sys­tems Biol­ogy in the Regen­er­at­ing Zebrafish Fin

regenerating zebrafish fin

Of the bony struc­tures in zebrafish, the regen­er­at­ing fin pro­vides a com­pelling sys­tem for enabling systems-based inves­ti­ga­tions of bone growth. Fol­low­ing fin ampu­ta­tion, osteoblasts at the stump de-differentiate to form a pro­lif­er­a­tive mass of cells called the blastema, and then re-differentiate to undergo bone for­ma­tion. The rate of bone growth dur­ing this process is remark­able, as new bone seg­ments are read­ily observed within 3–5 days fol­low­ing ampu­ta­tion (with the major­ity of lost bone, joints, nerves, skin and blood ves­sels restored within a few weeks). Inter­est­ingly, a grow­ing body of evi­dence indi­cates that the major phases of mam­malian osteoblas­tic dif­fer­en­ti­a­tion are reca­pit­u­lated dur­ing bone regen­er­a­tion in the fin. We are cur­rently inte­grat­ing novel bone phe­no­typ­ing tech­nolo­gies and exploit­ing the amenabil­ity of zebrafish to genetic manip­u­la­tion and high-throughput approaches to pur­sue large-scale, systems-based inves­ti­ga­tions of bone for­ma­tion and min­er­al­iza­tion in the regen­er­at­ing fin.

Sys­tems Mechanobiology

Sys­tems Mechanobiology

In recent years, mechan­i­cal sig­nals have become widely rec­og­nized as being crit­i­cal to the proper func­tion­ing of numer­ous bio­log­i­cal processes. This has led to the emer­gence of a new dis­ci­pline, cel­lu­lar mechanobi­ol­ogy, which bridges cell biol­ogy with var­i­ous dis­ci­plines of mechan­ics and which seeks to uncover the prin­ci­ples by which the sen­sa­tion or gen­er­a­tion of mechan­i­cal force reg­u­lates cell func­tion. A sec­ond com­po­nent of our research focuses on inves­ti­gat­ing mechanobi­o­log­i­cal processes using sys­tems biology-based approaches. An exam­ple of this can be seen in the above image, which depicts results from a genome-wide gene expres­sion screen for genes that are dif­fer­en­tially reg­u­lated by con­tin­u­ous and inter­mit­tent mechan­i­cal stim­u­la­tion. We are cur­rently devel­op­ing novel mechan­otrans­du­tion assays that will enable large-scale (1000s of sam­ples per day) assess­ments of mechanosen­sory func­tion. By inte­grat­ing these assays with avail­able tech­nolo­gies for high-throughput screen­ing, we seek to enable, for the first time, large-scale chem­i­cal and genetic screens for the dis­cov­ery of novel medi­a­tors of cel­lu­lar mechan­otrans­duc­tion. In addi­tion, using a com­bi­na­tion of genome-wide expres­sion analy­ses and bioin­for­mat­ics, we are devel­op­ing novel approaches for de novo dis­cov­ery of sig­nal­ing mech­a­nisms medi­at­ing cel­lu­lar mechanotransduction.