eNOS

Researchers are working to understand how protein quality control works in cells.  From plants to animals, all living things depend on proteins to help their cells function properly. In certain cases, like when under stress in response to heat or toxins, some proteins within the cell condense into liquid-like droplets called condensates. This process is hypothesized to occur via phase separation and provides a quick way for the cell to assemble certain components. Research in Syracuse University Professor Carlos Castañeda's lab has recently shown that protein quality control (PQC) components are important for many of these condensates. Castañeda, associate professor of biology and chemistry in the College of Arts and Sciences (A&S), is among a team of researchers working to understand how protein quality control works in cells. Similar to the way computers use coding as a set of instructions, the PQC receives its instructions from polyubiquitin chains. Ubiquitin (Ub) is a regulatory protein found in all eukaryotic cells (cells containing a defined nucleus) and polyubiquitin is an assembly containing at least a few ubiquitin molecules. Under normal operating conditions, condensates form and react to a stressor, and then dissolve after the stress is relieved. But when this system becomes disrupted, it can result in protein clumping or aggregation, which can cause cells, especially those in the nervous system, to die. These abnormal protein aggregates are markers for neurological diseases like amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease. By understanding the circumstances that lead to dysregulation of the PQC, scientists hope this research will one day lead to a cure for such neurodegenerative diseases. In a paper published last year in EMBO Reports, Castañeda and his collaborators established a framework for how polyubiquitin chains regulate the formation and disassembly of a condensate made of Ubiquilin-2 (UBQLN2) proteins, whose dysregulation is implicated in ALS. Polyubiquitin is important for UBQLN2 function and the two bind noncovalently, meaning that the interaction between them is weaker than a covalent chemical bond. Following up on that work, the researchers wanted to further explore the specific conditions that affect assembly of these condensates. "While working on the EMBO Reports project, we started to see that more extended polyubiquitin chains favored phase separation (condensate formation) with UBQLN2," says Castañeda. "So, we wondered if this is always true. We decided to make even more extended chains." Through the Research Experience for Undergraduates (REU) program, Castañeda welcomed students Suzanne Enos and Antara Chaudhuri into his lab in 2021. The NSF-sponsored REU program brings undergraduate students from across the country to Syracuse's campus to participate in research over the summer. In Castañeda's lab, the team engineered and designed different types of polyubiquitin chains with variable lengths and topologies. Enos and Chaudhuri then helped test how well these chains phase separated with UBQLN2. After further design-work by Sarasi Galagedera, a former postdoctoral researcher in Castañeda's lab; Thuy Dao, a lab manager in the Department of Chemistry; and Jeremy Schmit, a professor of physics at Kansas State University, the team found there was a "sweet spot" -- or specific spacing between Ub units -- where condensate formation was optimized. Fittingly coined as "goldilocks," the group's findings were recently published in Proceedings of the National Academy of Sciences (PNAS). "We found that there is an arrangements of ubiquitin units in polyubiquitin that is 'just right' for condensates to form," says Castañeda. "Ubiquitin units that are too far apart or too close together don't favor condensate formation as much. Jeremy Schmit used theoretical modeling and polyphasic linkage concepts to generalize these experimental observations." Furthermore, they uncovered that polyubiquitin in excess causes the condensates to disassemble. "In a cell, you can imagine that concentrations of polyubiquitin, as well as the spacing between ubiquitin units within different types of polyubiquitin, can up- or down-regulate condensate formation. You essentially have multiple ways to tune condensate formation with just adding this one polyubiquitin molecule," notes Castañeda. While their research merely scratches the surface of how polyubiquitin chains can regulate phase separation of condensates, Castañeda says it offers proof that these chains will be a main regulator of droplets. Future studies will involve adapting their rules to an in vitro system that models PQC to prove and test their theories in living cells. "This work provides a principle that can be applied to understanding how biomolecular condensates are generally controlled and will have large implications for anyone studying the regulation of their favorite biomolecular condensate," says Castañeda. The team's work was funded by the following grants: NIH R01 GM136946 awarded to Carlos Castañeda; NSF REU grant awarded to the Department of Chemistry; and NIH R01 GM141235 awarded to Jeremy Schmit.

Titan Medical is already working on the second generation of its Enos surgical robot and showing off the features in a new video. (You can watch the video at the bottom of this page.) Among other improvements, Enos 2.0 has a new trick up its sleeve. There is a third instrument arm, compared to the two instrument arms in the first generation. Toronto-based Titan Medical (Nasdaq:TMDI) has not yet filed for regulatory approval of the first generation. “With the time it takes to bring complex products to market in the regulated medical device industry, you must continuously envision the next generation.” Titan Medical CEO Cary Vance said in a statement. Titan Medical expects its Enos System to be first-to-market as a single-access, robotic-assisted surgical system, the company said in an investor presentation this week. The company has previously shared videos with computer renderings of Enos — formerly called “Sport” — as well as surgical demonstrations, but this appears to be the first video showing the system and its latest features in depth and detail. It’s not a bad way to draw more attention to the technology as Titan Medical explores its strategic options, which could include selling the business or another big move . Titan Medical said it met with strategic buyers and investors this week . “Our focus on purpose-driven innovation has always been at the forefront of our work,” Vance said. “We are excited to share our three-arm design that was independently created by Titan and builds upon technologies developed for our two-arm system and those generated under a previously executed and completed development and license agreement, and addresses evolving customer needs in single-access robotic surgery.” The Enos robotic surgery system’s instruments and features The Enos system uses a single port to enter a patient’s abdomen through the belly button for gynecological surgical procedures such as hysterectomies. Titan Medical said it has also optimized the system for urological and other general surgical procedures, but is focused on gynecological indications first. The Enos has a 25 mm cannula that it inserts through the single abdominal incision. The cannula has an integrated 2-D camera as well as a steerable 3-D endoscope. The integrated camera is used for insertion, pre-operative abdominal exploration and instrument entry. The endoscope works alongside the other instruments. Both cameras have high-definition resolution and illumination. In addition to the cameras, the first-generation Enos system can fit two multi-articulating instrument arms through the cannula. Enos 2.0 eliminates the integrated 2-D camera to make room for a third instrument arm. The Enos surgical robotics system’s suite of instruments includes: Monopolar hooks and shears for dissecting avascular planes and coagulation of small vasculature; Hunter and Maryland bipolar dissectors with an electric current that flows from tip to tip to safely seal larger vessels; Cold instruments such as the mega needle driver, suture cut, tenaculum, fenestrated and lap clinch effectors. These instruments have a continuous segment design for a broad range of motion in confined spaces while delivering the force and grip needed for surgical tasks, Titan Medical said. They’re designed for fluid movement and to allow the surgeon to do more work in less time with design features such as a minimally bending radius for enhanced triangulation and enhanced instrument travel along the axis. The arms are strong enough to retrieve larger organs. Enos 2.0 presents “opportunity to incorporate third-party instruments, accessories and digital technologies,” the company said in its investor presentation. The surgeon workstation has a medical-grade high-definition display screen and a dashboard that illuminates instrument status with interoperative overlays. Titan Medical designed the Enos system’s console with a small footprint. It’s compact enough that surgeons don’t need a dedicated operating room to use it. There are no external moving robotic arms and relatively few independent components, making the robot easier to drape for surgery — and faster to prepare for the next surgery. Read more about the Enos surgical robot system in this recent MassDevice interview with Titan Medical CEO Cary Vance.

The definitive agreement builds upon a development and license deal agreed in June 2020. Titan achieved all three milestones laid out in the agreement, including raising $18 million in capital in October 2020. It also received a $10 million payment for the second milestone and an additional $11 million for the completion of the third technical milestone. Titan received the final milestone payment from Medtronic in January. In May, Titan signed a $2.6 million purchase order from Medtronic. The latest deal between the two companies comprises a limited development program. It also includes a preclinical collaboration to evaluate instruments and cameras in gynecological procedures. The agreement also includes the potential for future activities associated with the commercial supply of instruments and cameras to Medtronic. It also finalizes the terms and conditions related to the May purchase order. “The closing of this Definitive Agreement is an advancement for our relationship with Medtronic, and for Titan as we move towards commercialization activities,” said Cary Vance, president and CEO of Titan. “We view the activities associated with this Definitive Agreement as additional methods of enhancing our know-how in single-access RAS technology and further benefitting our own Enos™ RAS platform.” Titan Medical is developing its Enos robotic single-access surgical system with an ergonomic focus. The aim is to offer a surgical experience imitating a surgeon’s real-life movements, with multi-articulating instruments, dexterity and the ability to exert the forces necessary to complete everyday surgical tasks. Titan initially plans to pursue gynecologic surgical indications for Enos.