Jetstream Venture Fund Backs Telomere-Targeting mRNA Startup

Jetstream Venture Fund has invested in Rejuvenation Technologies, a Stanford University spinout developing modified mRNA therapies that temporarily extend telomeres. Financial terms were not disclosed.

The deal gives Jetstream a third position in regenerative medicine. Rejuvenation Technologies joins Rejuvenate Bio, a gene therapy company spun out of Harvard research, and Wonderlab Bio, which is developing off-the-shelf cell therapies. Together, the three investments span mRNA, gene therapy and cell therapy platforms aimed at different aspects of cellular repair.

Rejuvenation Technologies targets serious age-related conditions, with lead programs in idiopathic pulmonary fibrosis and severe chronic liver disease. Both remain in preclinical development.

"Rejuvenation Technologies represents the kind of highly technical, paradigm-shifting science Jetstream seeks to identify early," said Chris Yoo, fund manager at Jetstream. "By adding their breakthrough mRNA platform alongside our existing stakes in Rejuvenate Bio and Wonderlab Bio, we are thrilled to offer our investors a seat at the table for disruptive technologies that could fundamentally alter how we treat chronic, age-related diseases."

The company grew out of Stanford research led by CEO and co-inventor Dr. John Ramunas. Its platform delivers modified mRNA through proprietary lipid nanoparticles to targeted organs. The approach is designed to produce temporary telomerase activity rather than permanently activating the enzyme.

According to the company, the transient treatment extends shortened telomeres and restores cellular regenerative capacity while avoiding the permanent changes associated with continuous telomerase activation. Telomeres are the protective structures at the ends of chromosomes that shorten as cells divide.

Rejuvenation Technologies has already attracted venture backing from Khosla Ventures and Y Combinator. It has also secured more than $8 million in non-dilutive grant funding from the National Institutes of Health and the California Institute for Regenerative Medicine.

For Jetstream, the deal sharpens a deliberate strategy: building exposure to longevity and regenerative medicine companies before those technologies reach later stages of clinical and commercial development. The fund's thesis holds that advances in gene therapy, mRNA delivery and cell engineering could create new approaches to diseases tied to aging and declining cellular function.

The portfolio companies cover distinct technical routes. Rejuvenate Bio is developing gene therapies for chronic and age-related diseases and has received backing from Merck Animal Health. Wonderlab Bio focuses on off-the-shelf cellular therapies. Rejuvenation Technologies adds the mRNA leg, targeting telomeres through a transient mechanism.

Jetstream itself is an interval fund managed by Xcellerant Ventures and Sweater Industries. Unlike traditional venture funds that serve institutional investors and high-net-worth limited partners, Jetstream seeks to give individual investors access to venture-backed private companies through lower investment minimums and without carried interest. The structure lets the fund aggregate capital from a wider investor base and deploy it into private businesses that historically have been difficult for retail investors to access directly.

The Rejuvenation Technologies position is the earliest-stage component of that strategy. While telomere-targeted therapies carry significant potential applications, the company's lead programs remain preclinical and will require substantial development and testing before any potential commercialization.

Jetstream is nonetheless increasing its capital allocation to the longevity thesis, and the fund now holds exposure to the full development trajectory of regenerative medicine — from preclinical mRNA science to later-stage gene and cell therapy programs.