Steroid-cationic lipid compound and use thereof

A lipid compound as shown in formula (I),

• or a stereoisomer, a tautomer, and a pharmaceutically acceptable salt thereof, wherein,
• Xa and Xb are each independently selected from
• R4 is C1-C6 alkyl;
• q is an integer of 1 or 2;
• Z and Z′ are each independently selected from S, C, or a chemical bond;
• R1a and R1b are each independently selected from C1-6 alkylene or C3-C8 cycloalkylene;
• R2a and R2b are each independently selected from C1-6 alkylene;
• Ya and Yb are independently selected from:
• —O—, —O(C═O)O—, —(C═O)NRa-, —NRa(C═O)—, —NRa—, —O(C═O)—, —(C═O)O—, —C(═O)—, —S(O)x-, —S—S—, —C(═O)S—, —SC(═O)—, —NRaC(═O)NRa—, —OC(═O)NRa—, —NRaC(═O)O—, —OC(═O)S—, or —SC(═O)O—;
• Ra is H or C1-C12 alkyl;
• m and n are each independently selected from 1, 2, or 3;
• R3a and R3b are selected from a naturally occurring or non-naturally occurring steroid group, a fat-soluble vitamin residue, C6-C24 alkyl, C6-C24 monoalkenyl or polyalkenyl, or C6-C24 monoalkynyl or polyalkynyl, wherein CH2 on the alkyl, alkenyl, or alkynyl is optionally replaced by one or more oxygen atoms;
• provided that at least one of R3a and R3b is a naturally occurring or non-naturally occurring steroid group.