Replacing specific characters in first column of text

I have a text file and I'm trying to replace a specific character (.) in the first column to another character (-). Every field is delimited by comma. Some of the lines have the last 3 columns empty, so they have 3 commas at the end.

Example of text file:

abc.def.ghi,123.4561.789,ABC,DEF,GHI
 abc.def.ghq,124.4562.789,ABC,DEF,GHI
 abc.def.ghw,125.4563.789,ABC,DEF,GHI
 abc.def.ghe,126.4564.789,,,
 abc.def.ghr,127.4565.789,,,
 

What I tried was using awk to replace '.' in the first column with '-', then print out the contents.

ETA: Tried out sarnold's suggestion and got the output I want.

ETA2: I could have a longer first column. Is there a way to change ONLY the first 3 '.' in the first column to '-', so I get the output

abc-def-ghi-qqq.www,123.4561.789,ABC,DEF,GHI
 abc-def-ghq-qqq.www,124.4562.789,ABC,DEF,GHI
 abc-def-ghw-qqq.www,125.4563.789,ABC,DEF,GHI
 abc-def-ghe-qqq.www,126.4564.789,,,
 abc-def-ghr-qqq.www,127.4565.789,,,
 

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