mrgnfi is a spot borrow and lending app on Solana. They have integrated JitoSOL. You can borrow USDC or other assets against the value of your JitoSOL.
You can also use mrgnfi for levered staking on JitoSOL. This involves depositing JitoSOL, borrowing SOL against that value, converting the borrowed SOL into JitoSOL, depositing it and withdrawing more SOL in a circular loop. The effect of this is to amplify the staking returns from JitoSOL.
Regular returns on JitoSOL are 6-8%. This method can produce returns of 15% or greater, albeit with some risk. Read more about the concept here and please make sure you understand the risks before initiating any DeFi strategies.